FIELD OF THE INVENTION
The present invention relates to the field of construction of energy efficient buildings. Moreover, the present invention relates to panelized, superinsulated building systems and methods.
BACKGROUND OF THE INVENTION
In the design and construction of buildings, it is well known that energy efficiency and building insulation go hand in hand. Accordingly, numerous types of insulation systems and methods exist. Within typical “stick built” construction using framed lumber, voids are created within walls. In such exterior walls, these voids are often filled with fiberglass, cellulose-based, or foam material which have varied insulative value. Vapor barriers are typically added to such exterior walls in order to enhance the insulative effect. However, due to the nature of such framed lumber, thermal bridging often detrimentally occurs to facilitate heat transfer within walls. As well, a variety of leakage points exist due to difficulties inherent to current vapor barrier technology.
Improvements have been attempted in the form of structural insulated panels (SIPs) which are a high performance building system for residential and light commercial construction. The panels consist of an insulating foam core (e.g., extruded polystyrene XPS or expanded polystyrene EPS foam) sandwiched between two structural facings, typically oriented strand board (OSB). SIPs are manufactured under factory controlled conditions and can be fabricated to fit nearly any building design. The result is a building system that is extremely strong, energy efficient and cost effective. Disadvantageously however, standard SIP technology typically requires spline joints which connect the panels together while allowing thermal bridging to occur.
In order for more new construction to be energy efficient and durable against the moisture-related problems that are sometimes associated with thick, airtight assemblies, new construction methods are required. The assemblies that will perform best from energy and resiliency viewpoints are inherently complex, time-consuming to assemble, and require specialized training to execute effectively.
It would be advantageous to obviate or mitigate these disadvantages such that heat transfer between building interiors and exteriors, thermal bridging, and leakage are substantially reduced or eliminated.
SUMMARY OF THE INVENTION
The present invention provides a system and method for panelized, superinsulated building envelopes that reduces or substantially eliminates many problems in building construction including heat transfer between building interiors and exteriors, thermal bridging, and leakage. The present invention reduces contributions to climate change due to wasted energy in the built environment. Difficulties in quality control for and time required on site to build complicated building envelope assemblies are minimized by way of the present invention.
The present invention reduces moisture-related issues, including reducing problems from mold inside building envelopes that are not vapor-open to the exterior and improving cladding longevity in building assemblies without a rain screen detail. The present invention also reduces moisture-related problems, including mold, in building assemblies insulated to higher levels than required by building codes.
The present invention provides effective air-sealing of building assembly panels, maintains integrity of the air barrier during and after the construction process, and provides enhanced insulating of “marriage joints” between building assembly panels.
The present invention overcomes difficulties in providing continuity of a weather resistant barrier between building assembly panels and resolves both problems related to vapor open construction of exterior and interior corners and also difficulties in building exterior and interior corners without thermal bridges.
The present invention also provides connections from wall to roof and at window and door supports that are free of thermal bridging.
The present invention enables a window assembly allowing for drainage into the rain screen, behind the cladding.
The present invention provides a service cavity on the inside of a building envelope assembly.
The present invention also provides effective insulation and air sealing of bother concrete slab foundations as well as foam-free pier foundations.
The present invention provides these benefits and solves these problems by using specific assemblies constructed in a controlled shop environment by skilled workers, then assembled on site using prescribed details. Anyone building a new home, new commercial or institutional building, or building significant additions to existing structures may benefit from the present system and method. Because most of the cost is in building and installing the panels, with travel costs as a comparatively minor expense, the system and method of the present invention effectively enables building houses in any location so as to bring low-energy, high-performance buildings to anyone constructing a building.
According to a first aspect of the invention there is provided a system for constructing an energy efficient building, the system includes: at least one panelized structure having a structural layer including a first set of voids and located at an inner area of the at least one panelized structure, the inner area being adjacent to intended living space of the energy efficient building, an airtight layer formed by a first sheathing layer providing a primary air barrier and a vapor retarder exterior to the structural layer, a blanket layer located exterior to the first sheathing layer and formed by a plurality of vertical members with a second set of voids located between each of the vertical members, a weather resistant barrier located exterior to the blanket layer and including a second sheathing layer formed by an airtight, water-repelling, vapor-open fabric, a rain screen located exterior to the weather resistant barrier, the rain screen being adjacent to outdoor space external to the energy efficient building and including a drainage plane internal thereto, the drainage plane for channeling moisture away from the weather resistant barrier; insulation for placement within the structural layer and the blanket layer; and wherein the at least one panelized structure is air-sealed and insulated within the first and second sets of voids after installation.
According to a second aspect of the present invention there is provided a panelized wall structure for constructing an energy efficient building, the panelized wall structure includes: a structural layer having a first set of voids and located at an inner area of the panelized wall structure, the inner area being adjacent to intended living space of the energy efficient building; an airtight layer formed by a first sheathing layer providing a primary air barrier and a vapor retarder exterior to the structural layer; a blanket layer located exterior to the first sheathing layer and formed by a plurality of vertical members with a second set of voids located between each of the vertical members; a weather resistant barrier located exterior to the blanket layer and including a second sheathing layer formed by an airtight, water-repelling, vapor-open fabric; and a rain screen located exterior to the weather resistant barrier, the rain screen being adjacent to outdoor space external to the energy efficient building and including a drainage plane internal thereto, the drainage plane for channeling moisture away from the weather resistant barrier.
According to a third aspect of the present invention there is provided a panelized roof structure for constructing an energy efficient building, the panelized roof structure for constructing an energy efficient building, the panelized roof structure includes: a structural layer having a first set of voids and located at an inner area of the panelized roof structure, the inner area being adjacent to intended living space of the energy efficient building; an airtight layer formed by a first sheathing layer providing a primary air barrier and a vapor retarder exterior to the structural layer; a blanket layer located exterior to the first sheathing layer and formed by a plurality of vertical members with a second set of voids located between each of the vertical members; a weather resistant barrier located exterior to the blanket layer and including a second sheathing layer formed by an airtight, water-repelling, vapor-open fabric; and a rain screen located exterior to the weather resistant barrier, the rain screen being adjacent to outdoor space external to the energy efficient building and including a drainage plane internal thereto, the drainage plane for channeling moisture away from the weather resistant barrier.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:
FIG. 1 is a cross sectional side view of a south facing building sidewall from ground to roof which illustrates various building parts where the present invention may be embodied.
FIG. 2 is a schematic cross-sectional side view showing wall o raft slab details incorporating the present invention.
FIG. 3 is a schematic cross-sectional side view showing a heated basement detail having trussed flooring and incorporating the present invention.
FIG. 4 is a schematic cross-sectional side view showing an unheated basement detail having trussed flooring and incorporating the present invention.
FIG. 5 is a schematic cross-sectional side view showing an unheated basement detail with I-beam supported flooring and incorporating the present invention.
FIG. 6 is a schematic cross-sectional top view showing an exterior corner detail incorporating the present invention.
FIG. 7 is a schematic cross-sectional top view showing marriage joint detail incorporating the present invention.
FIG. 8 is a schematic cross-sectional top view showing an interior corner detail incorporating the present invention.
FIG. 9 is a schematic cross-sectional top view showing an exterior wall to partition wall detail incorporating the present invention.
FIG. 10A is a schematic cross-sectional side view showing a door head detail incorporating the present invention.
FIG. 10B is a schematic cross-sectional side view showing a door sill to slab detail incorporating the present invention.
FIG. 11B is a schematic cross-sectional plan view showing a fixed window detail incorporating the present invention.
FIG. 11B is a schematic cross-sectional plan view showing an operable window detail incorporating the present invention.
FIG. 12A is a schematic cross-sectional side view showing a fixed window head detail incorporating the present invention.
FIG. 12B is a schematic cross-sectional plan view showing a fixed window sill detail incorporating the present invention.
FIG. 12C is a schematic cross-sectional side view showing an operable window head detail incorporating the present invention.
FIG. 12D is a schematic cross-sectional plan view showing an operable window sill detail incorporating the present invention.
FIG. 13 is a schematic cross-sectional side view showing floor to floor gable wall marriage detail incorporating the present invention.
FIG. 14 is a schematic cross-sectional view through a panelized roof incorporating the present invention.
FIG. 15 is a schematic cross-sectional view through a panelized roof showing eave detail and incorporating the present invention.
FIG. 16 is a schematic cross-sectional view through a panelized roof showing ridge detail and incorporating the present invention.
FIG. 17 is a schematic cross-sectional view through a trussed roof incorporating the present invention.
FIG. 18 is a schematic cross-sectional view through a low slope pitch roof incorporating the present invention.
DETAILED DESCRIPTION
The present invention is a system and method which provides panelized, superinsulated building envelopes. In general, panel sections in accordance with the invention are shop-fabricated as completed assemblies or as partial assemblies and are installed as components on a building site. Assemblies in accordance with the present invention may include wall, roof, and floor assemblies. Such assemblies provide a new and useful alternative to standard SIPs such that the inventive assemblies are both thermal bridge free and foam free.
All assemblies in accordance with the present invention are designed and constructed to be highly energy efficient, resilient and durable, and to meet the voluntary International Passive House building energy standard and/or the Passive House Institute of the United States building energy standard. It should be understood that all parts of each building component or assembly are equally important to the overall inventive system and method in order to meet ideal building envelope performance goals and the aforementioned energy standard.
With specific reference to the figures below, it should be understood that like parts exists in more than one figure. As such, each like part is numbered identically when like structures are used throughout the various embodiments. For clarity, only the first occurrence of such structures may be described in detail where subsequent figures may not include a repeated description of like structures.
With reference to the drawings, FIG. 1 is a compilation which illustrates a variety of assemblies (shown in cross section) which, once joined together on a building site with typical other building components, form a panelized, superinsulated building envelope embodying the invention. The inventive aspects of the present invention therefore include the inventive assemblies, the building system incorporating the assemblies, and the method by which the assemblies thereby form the panelized, superinsulated building envelope. In particular, FIG. 1 is a cross sectional side view of a south facing building sidewall from ground to roof which illustrates various building parts where the present invention may be embodied. Here, a ground level section 4, mid-floor section 5, and roof section 6 can be seen with first floor window 3 and second floor window 2 located between sections. The inventive components in FIG. 1 include panel assemblies 4a, 5a, 5c, and 6c which will be further described in more detail related to FIGS. 2 through 18. Commonly understood components such as foundation 4b, suspended flooring 5d, roofing structure 6d, exterior roofing 6a are also shown and which are pertinent to the present discussion as they provide context in terms of implementation of the present invention, though are not of particular importance in their specific design as configurations may change given the particular building architecture and/or site requirements. As well, exterior overhangs 5b, 6b to shield direct sunlight rays (shown as dotted line 1) are provided as shading devices which may be sized and located so as to provide solar shading of the exposed window frame.
With regard to FIG. 2, there is shown a schematic cross-sectional side view showing wall to raft slab details incorporating the present invention. Here, a panelized wall section in accordance with the invention is secured atop a concrete slab 25. Beneath the slab 25 is foundation insulation 24 preferably formed from 12-inch type II borate treated expanded polystyrene (EPS) foam insulation. Mating pieces of additional foundation insulation 20 surround the periphery of the slab 25 and are placed under the overhanging end sheathing 18. The additional foundation insulation is preferably formed from 12-inch type IX borate treated EPS foam insulation. As shown, typical groundwork is provided including large composition structural fill 21 and perimeter drain 23 run to daylight with a fabric 22 overlaid atop the drain 23 such that the filter fabric separates granular fill from larger composite structural fill over 4-inch.
As mentioned above, the present invention may be incorporated within a building having a raft slab. As seen in FIG. 2, a concrete slab-on-grade foundation is a raft slab whereby blocks made from borate-treated EPS (expanded polystyrene) are provided below the concrete. Borate-treated EPS has been found to be the most durable and benign plastic foam for this location. The EPS blocks may be configured using dado and tenon joinery so as to easily lock together block pieces. The interlocked blocks therefore protect the concrete slab from thermal loss, isolating the interior from radon and water vapor, and acting as a concrete form—all in one system. Once the raft slab insulation is placed, an 8-inch steel-reinforced concrete slab is poured which is thick enough that separate footings are not required under point loads. The floor is polished and sealed as a finished floor, or covered with another material. The present invention incorporating such foundation system is certified by the International Passive House Institute to be free of thermal bridging, with a U value of 0.12 W/m2K (0.021 Btu/hr ft2 ° F.), ≈R 47.6.
During installation, it is advantageous to install the walls on top of the foundation vapor barrier to complete the air barrier. As well, the use of adhesive sealant will complete the air barrier connection from wall to foundation.
The panelized wall section portion of FIG. 2 includes elements which can be grouped into five (5) basic categories. Indeed, all panelized sections discussed herein below in accordance with the present invention includes elements that may also be grouped similarly into such five (5) basic categories. These categories of elements include the structural layer, the airtight layer, the blanket layer, the weather resistant barrier, and the rain screen.
The structural layer forms an inner, structural wall. In FIG. 2, this can be seen by internal wall 34 which is preferably 2×4 studs arranged 24-inch on center of #2 SPF (spruce-pine-fir) or better per NELMA (Northeastern Lumber Manufacturers Association). The base of internal wall 34 includes a continuous 2×4 bottom plate 26. The bottom plate 26 secures the panelized wall section to the slab 25 via an anchor bolt 28. The structural layer may also include internal surfacing of gypsum sheetrock 33 or any suitable interior surfacing product for the given implementation. Within the voids between studs of the internal wall 34, there is also provided mineral wool insulation 32.
The interior, structural wall 34 carries all structural loads, with most insulation on the exterior, though it is left uninsulated, as a “service cavity,” until after the building envelope is complete so as to facilitate panel attachments, mechanical, and electrical work.
The airtight layer provides a structural diaphragm that is also the primary air barrier and vapor retarder on the outside of the structural layer. In terms of FIG. 2, this provided by the continuous 2×4 bottom plate 26 being wrapped with a weathertight tape such as Tescon Extoseal® sill tape available from Pro Clima® of Schwetzingen, Germany or any suitable weathertight tape. As well, the anchor bolt 28 is set in epoxy adhesive 27 to ensure weathertight seal of bottom plate 26 to the slab 25. A first sheathing layer 30 is provided adjacent to the internal wall 34. This first sheathing layer 30 is preferably constructed of a suitable weathertight coated OSB (oriented strand board) such as 7/16-inch ZIP® sheathing available from Huber Engineered Woods LLC of Charlotte, N.C.
The first sheathing layer 30 is rendered airtight with all joints and nail holes taped with a suitable weatherproof taping such as Tescon Vana® adhesive tape with fleece backing available from Pro Clima® or any suitable weathertight tape. Lastly, a vapor barrier 19 is provided to separate the slab 25 from the exterior insulation 20, 24. The vapor barrier 19 may be a continuous ten (10) mil polyethylene sheet or any suitable material that functions as air barrier and capillary break. Thus, a contiguous airtight layer is formed by the first sheathing layer 30 and vapor barrier 19 which are connected in a weathertight manner at the continuous bottom plate 26. Moreover, it is beneficial that the airtight layer is placed in a protected location, internal to the panelized wall structure.
The blanket layer is an exterior insulating layer that includes vertical members filled between with insulation. It should be noted that the blanker layer is vapor open. As shown in FIG. 2, each vertical member is an I-joist 29. Each I-joist 29 is preferably an 11⅞ inch I-joist arranged 24 inches on center with SPF flanges and OSB webs. Between each I-joist 29 is a void which is filled with a dense pack cellulose insulation 14 or similar suitable insulating material. The blanket layer is held to the structural layer by suitable screws 31 as shown and which are preferably 5/16″×4″ RSS™ lag screws fastened at two feet on center and staggered. RSS™ lag screws are a rugged structural screw made of specially hardened steel and available from GRK Fasteners of Schaumburg, Ill.
It should be understood that the “I-joists” referred to herein are an engineered wood product consisting of solid wood or laminated wood flanges and structural sheet material such as plywood or OSB as the web and which are advantageously placed outside the structural wall and air barrier, as support for cladding and insulation. Attaching the I-joists to the structural wall with structural screws thereby also is an advantage as the panelized wall structure relies upon screws as the only structural support for the blanket layer. For purposes allowing air evacuation when installing blown insulation, holes may be drilled in the I-joists of the blanket layer and covered with air-permeable mesh. Cellulose insulation may be installed more densely than normal, at 4.0 to 4.25 pounds per cubic foot, to ensure that such insulation remains in place during transport and for the life of the building.
The blanket layer is insulated with cellulose to a minimum density of 4.0 lbs/ft3, denser than typical to prevent settling in the present invention's larger-than-typical insulation cavities. The hygroscopic nature of cellulose insulation serves as a moisture buffer and a mineral borate additive makes the cellulose fireproof as well as resistant to pests. Testing has shown that over time, the moisture content within the walls fluctuates slightly, tracking environmental conditions, but that it stays far below the levels required for mold growth.
With continued reference to FIG. 2, the weather resistant barrier is formed partly by a second sheathing layer 11. This second sheathing layer 11 is made of an airtight, water-repelling, vapor-open fabric that is resistant to outdoor weather. The second sheathing layer 11 should be a vapor-variable product which protects against water vapor movement with a low permeance (e.g., of 0.17 Perms, on the cusp of a class 1 and class 2 vapor retarder, but opens to 13.20 Perms (a class 3 vapor retarder)) which allows for drying in the presence of high moisture content. The membrane is reinforced to allow it to support dense-packed cellulose. Preferably, the second sheathing layer 11 is fabricated from a continuous Solitex Mento Plus® weather resistant barrier from Pro Clima® with all joints taped with Tescon Vana® adhesive tape with fleece backing available from Pro Clima® or any suitable weathertight tape. Additionally, the overhanging end sheathing 18 is also resistant to outdoor weather. Preferably, the overhanging end sheathing 18 is constructed similar to the first sheathing layer 30 and is preferably constructed of a suitable weathertight coated OSB (oriented strand board) such as 7/16-inch ZIP® sheathing and rendered airtight with all joints and nail holes taped with a suitable weatherproof taping such as Tescon Vana® adhesive tape or any suitable weathertight tape. Thus, the second sheathing layer 11 and end sheathing 18 as a bottom plate to encapsulate the blanket layer. Moreover, it should be understood that sheet goods (plywood or OSB) at the top and bottom of the I-joists 29 are provided as top and bottom plates to create a cavity for blown insulation.
The fifth category of grouped elements of the panelized wall section in accordance with the present invention is the rain screen which includes the outermost parts shown in FIG. 2 adjacent the exterior of the second sheathing layer 11. Vertical strapping 12 is provided over the second sheathing layer 11 and preferably formed by 1×3 SPF arranged 12″ on center. Upon the vertical strapping 12 is secured horizontal strapping 13 preferably formed by 1×3 SPF arranged 24′ on center. The vertical strapping 12 and horizontal strapping 13 therefore form two layers of furring material in a “flying batten” configuration to create a freely draining “rain screen” drainage plane. The flying battens are off-layout strips formed of the 1×3 strapping as mentioned and are used to keep the second sheathing layer 11 from pushing too far into the rain screen during and after cellulose installation. The final outer layer of siding 15 is provided in any typical manner such as standard ¾ inch wood siding or as desired for the given building's exterior decor requirements.
The vertical strapping 12 provides a gap at the bottom end thereof where wall vent 16 is inserted. Preferably, the wall vent 17 is SV-5 Siding Vent available from Cor-A-Vent, Inc. of Mishawaka, Ind. or any suitable heat-resistant webbing made from profile extruded polypropylene plastic that functions as a drainage mat for moisture collected in the area behind the siding 15. It should also be noted that a termite shield 17 may be provided as is typical to ward off wood eating insects. It should also be noted that it is advantageous that the I-joists 29 are not bearing the on the concrete slab 25.
Having discussed above what is fundamentally the basic component of the present invention, namely a panelized wall section, it should be understood that the following discussion of subsequent FIGS. 3 through 18 are combinations of a variety of configurations of panelized wall sections in accordance with the present invention. As such, they are meant as illustrative of some of the possible variations of the present invention, though other combinations and sub-combinations may be well within the intended scope of the present invention without straying from the invention.
FIG. 3 includes several identical parts as previously shown and described with regard to the panelized wall section portion of FIG. 2. As such, those identical parts will not be again described, but rather the differentiated parts will be discussed with regard to FIG. 3. More specifically, FIG. 3 shows a schematic cross-sectional side view showing a heated basement detail having trussed flooring and incorporating the present invention. Here, a section of suspended flooring structure is provided above a heated basement. The suspended flooring structure includes a rimboard 35 abutting the first sheathing layer 30. Web joists 37 are situated against the rimboard 35 and the bottom ends of each web joist 37 rest upon a sole plate 38. Subfloor 36 is provided in a known manner across each web joist 37. In this configuration, it should be noted that the internal wall 34 of the panelized wall section resides atop the subfloor.
As the sole plate 38 is within the heated building envelope, it need not be wrapped as was the bottom plate 26 shown in FIG. 2. The sole plate 38 is secured in a typical fashion via anchor bolt 28 to the foundation wall 39. Likewise, in typical fashion, a footing 43 supports the foundation wall 39. A break 100, common to this and several following figures, in the foundation wall 39, foundation insulation 24, and fill 21 is shown to indicate that the height of the foundation structure may be longer than is shown. As the foundation insulation 24 is foam which would otherwise degrade when exposed to sunlight and weather, a layer of cement board 40 will normally be provided and typically will include a parge coat.
With continued reference to FIG. 3 and forming part of the weather resistant barrier, there is provided waterproofing 41 on the exterior of the foundation wall 39. Such waterproofing 41 is typically a fluid provided membrane known in the art. Likewise, a capillary break 42 will be provided between the foundation wall 39 and the footing 43. The weather resistant barrier is thus formed in the embodiment of FIG. 3 by the first sheathing layer 30 contiguously with the waterproofing 41, capillary break 42, and vapor barrier 19.
FIG. 4 is similar to FIG. 3 except that the basement area is unheated. Specifically, FIG. 4 is a schematic cross-sectional side view showing an unheated basement detail having trussed flooring and incorporating the present invention. In such configuration, the weather resistant barrier providing the building's internal envelope excludes the basement area. Here, it should be noted that cellulose insulation 14 is provided within the suspended floor structure among each web joist 37. Moreover, a membrane 44 is provided under suspended floor structure against the bottom side of each web joist 37, running atop the sole plate 38, and sealed to the first sheathing layer 30. Such membrane 44 is preferably a high performance airtight vapor control layer such as Pro Clima® DA membrane. Thus while the waterproofing 41, capillary break 42, and vapor barrier 19 contiguously provide a barrier layer to the unheated basement area, the weather resistant barrier in the configuration shown in FIG. 4 is primarily provided by the membrane 44 and the first sheathing layer 30.
FIG. 5 is similar to FIG. 4 except that the suspended floor structure is more akin to the panelized wall section. Specifically, FIG. 5 is a schematic cross-sectional side view showing an unheated basement detail with I-beam supported flooring and incorporating the present invention. The I-beams 46 are preferably 24 inches wide and placed 16 inches on center. The I-beams 46 are engineered wood joists such as TJI® Joists available from Weyerhaeuser of Federal Way, Wash. A lower sheathing layer 45 is provided on the underside of the I-beams 46 and is structural in its function as well as forming part of the weather resistant barrier in this embodiment. Like the first sheathing layer 30, the lower sheathing layer 45 is rendered airtight with all joints and nail holes taped with a suitable weatherproof taping such as Tescon Vana® adhesive tape with fleece backing available from Pro Clima® or any suitable weathertight tape. In this embodiment, the primary airtight layer is formed by the first sheathing layer 30 contiguously with the lower sheathing layer 45.
A corner connection between two panelized wall sections in accordance with the present invention is shown in FIG. 6 as a schematic cross-sectional top view showing an exterior corner detail. Dotted line 200 denotes the panel break between the two panelized wall sections. Here, the screws 31 can be seen attaching each I-joist 29 to studs in of the internal walls 34 so as to attach the blanket layer to the structural layer. Because such screws 31 can effectively break the airtight layer, portions of taping 50 are provided suitable to prevent leakage at those locations. Taping 50a is also provided at the exterior connection between panelized wall sections.
With further regard to FIG. 6, the ends of each panelized wall sections can be seen to include insulation board 49 which is light weight stone wool insulation board such as ProRox® SL 960 made by ROXUL INC. of Milton, Ontario. Structural integrity of the panelized wall sections at the corners is enhanced by the addition of corner sheathing 51 which may be formed from a section of OSB. At the corner interior, structural integrity is provided by a C-stud formed by SPF studs 47a, 47b, 47c arranged in a C-configuration with a foam insulation 48 located within any void created at the center of the C-stud. In this configuration, the airtight layer is formed by each first sheathing layer 30 and assured by taping 50, 50a.
At outside corners of walls, holding I-joists back from the ends of the airtight layer facilitates air sealing the vertical seam at the outside corner where the airtight layer of two panels meet. It may be useful to build one panel with extra second sheathing layer 11 to be unfurled and sealed to the adjacent panel after air sealing is complete. It is also possible to use a solid sheet of sheathing material on one face only of the rain screen layer, to facilitate panel connections while allowing the wall to remain vapor-open at the adjacent face.
FIG. 7 is a schematic cross-sectional top view showing marriage joint detail between panelized wall sections according to the present invention. Again, dotted line 200 denotes the panel break. Here, the insulation boards 49 are seen to abut. As well, it should be understood that the second sheathing layer 11 is provided between abutting insulations boards 49. Taping 50 assures the airtight layer is contiguous between each first sheathing layer 30. It may be also useful in configurations such as this, where two wall panels meet in line, to break the panels off-layout (e.g., at 12″ for 24″ on center stud layout) to facilitate air sealing at those locations. As well, it may be useful to build one panel with extra second sheathing layer 11 so as to be unfurled and sealed to the adjacent panel after air sealing is complete.
FIG. 8 is a schematic cross-sectional top view showing an interior corner detail incorporating the present invention. Here, an internal wall 34 is seen wrapping around an end of one panelized wall section where a C-stud is formed by studs 47a, 47b, and 47c so as to provide structural integrity to the corner section. It should also be noted that the second sheathing layer 11 extends across both insulation boards 49.
At inside corners of walls, holding I-joists back from the inside corner may allow workers to reach into the deep framing cavity to air-seal the vertical connection at the inside corner. It may be useful to build one panelized wall section of the inside corner with extra second sheathing layer 11 to be unfurled and sealed to the adjacent panel after air sealing is complete. As well, it may be useful at inside corners of walls to connect the rain screens at adjacent panels with an L-shaped assembly of OSB or other sheet stock, to provide a nailing base for siding.
FIG. 9 is a schematic cross-sectional top view showing an exterior wall to partition wall abutting against one panelized wall section in accordance with the present invention. In this configuration, the weather resistant barrier formed by first sheathing layer 30 remains intact and uninhibited by a partition wall 34a. Here, an end stud of the partition wall 34a is joined to the panelized wall section by way of a backer sheet 52a which may be a section of plywood provided as a backing to drywall 33 and into which the end stud of partition wall 34a may be suitably fastened by way of screws.
FIGS. 10A and 10B illustrate a sliding glass doorway within a panelized wall section embodying the present invention. In particular, FIG. 10A shows a schematic cross-sectional side view showing a door head detail while FIG. 10B is a schematic cross-sectional side view showing a door sill to slab detail.
With reference to FIG. 10A, a nailer 52b is shown which may be formed by a 1½″×1½″ section of SPF and to which a plywood buck 59 may be suitably fastened. The plywood buck 59 is a section of plywood suitably wrapped with a weathertight tape and creating a window buck and which is taped via taping 50 to a header 60 to create a contiguous air barrier as part of the overall weather resistant barrier. The header 60 provides structural integrity to the door opening and is integrated into the edge of internal wall 34 adjacent the plywood buck 59. Outer door frame 57a operatively integrates with inner door frame 57b in a known manner.
Window and door bucks (i.e., framing elements that surround and support the fenestration) may be of two main parts, inner bucks and outer bucks. The inner bucks are the structural support for the fenestration, and are from 1⅛″ to 1½″ thick, located inside the structural wall rough opening, extending to the inside of the structural wall. The outer bucks are thinner, from 7/16″ to ¾″ thick, placed outside and overlapping the inner bucks, extending to the outside of the blanket layer. The buck assembly is wrapped with one or more layers of solid wood to stiffen the assembly and to provide a nailing surface. The two-step buck assembly serves to minimize thermal bridging, provides positive placement for the fenestration, and allows for insulation and drainage around the window frame.
Glass 56 is preferably at least double paned with a warm edge “Swiss spacer” 55 provided so as to proved enhanced insulative value. As well, triple-pane glass panels perform even better than the well-insulated frames it is preferably that all exterior doors to be glass when used in the context of the present invention. Gaps between the plywood buck 59 and the outer 54a and inner 54b trim boards is filled respectively with foam type insulation 53 and 58 respectively. In particular, insulation 53 is preferably in the form of a high quality insulating foam panel which may be easily fashioned into the particular shape as shown, while insulation 58 may be in the form of water cured butyl fired urethane foam which may be injected into the corresponding space. In this manner, insulation 53 may be wrapped as shown with taping 50 to further enhance the airtight layer. It should be noted that windows are placed near the center of the wall thickness which may provide aesthetic benefits as well as space for post-installation window treatments.
The high performance panelized wall sections of the present invention relatedly require high performance windows and exterior doors. The present invention therefore works best in conjunction with exterior doors that seal securely against air and water infiltration. As well, triple-pane glass panels are preferred. It is also preferable that all exterior doors to be glass when used in the context of the present invention.
FIG. 10B shows the opposite end from FIG. 10A where an exterior sill 61 abuts a lower frame 62 fabricated preferably from a polyurethane product based on rigid foam with a high thermal insulating value such as Purenit® available from Puren gmbh of Überlingen, Germany. A vapor barrier 19 is contiguously provided under the lower frame 62 and along the slab 25 adjacent to foundation insulations 20, 24. In this manner, the airtight layer is formed by the double pane glass 56, spacer 55, inner door frame 57b, and vapor barrier 19. In general, doors are preferably placed so they bear partly or in whole on the concrete slab.
FIGS. 11A through 12D show variations substantially similar to the structure already shown and described in FIGS. 10A and 10B, but related to fixed and operable windows.
FIGS. 11A and 11B are schematic cross-sectional plan views showing, respectively, a fixed window detail and an operable window detail incorporating the present invention with similar structure and function of elements shown and described with regard to FIGS. 10A and 10B. It should be noted in both the placement of second sheathing layer 11 extends around nailer 52b and the insulation 53 thereby ensuring a contiguous airtight, water-repelling, vapor-open barrier to the blanket layer in either configuration.
FIGS. 12A through 12D are substantially similar to the header and sill configurations of FIGS. 10A and 10B except that these additional figures schematic cross-sectional side views showing a fixed and operable window head and sill details incorporating the present invention, thus parts are similarly labeled. In each, it should be understood that the airtight layer maintains the building envelope contiguously via the first sheathing layer 30, the plywood buck 59 suitably wrapped with a weathertight tape, the window frames (57a through 57c, depending upon the fixed or operable configuration shown), and window glass 56, along with suitably placed taping 50 as shown.
In FIG. 13 there is shown a schematic cross-sectional side view showing an example of a floor to floor gable wall marriage detail incorporating panelized wall sections in accordance with the present invention. Here, “marriage joints” allowing each panel to be air-sealed and insulated after panel installation. Again, the panel break 200 is shown to better view the separation between panelized wall sections. Here, the interface between panelized wall sections includes a set of horizontally oriented I-joists 63, preferably formed by an 11⅞ inch I-joist arranged 24 inches on center with SPF flanges and OSB webs. Each horizontally oriented I-joist 63 perpendicularly abuts the end of each I-joist 29.
With further regard to FIG. 13, a pair of insulation boards 49 are provided within the opposing voids in each horizontally oriented I-joist 63. It should also be noted that that second sheathing layer 11 is provided across insulation boards 49 thereby ensuring a contiguous airtight, water-repelling, vapor-open barrier to the blanket layer in either configuration. The flooring section includes web joists 37 of which the outermost one abuts the first sheathing layer 30 and rests between internal walls 34, specifically upon top plate 65 as shown. Taping 50 is provided at the joining of each horizontally oriented I-joist 63 against the adjacent first sheathing layer 30 to provide contiguity in the airtight layer. Extending the first sheathing layer 30 above the blanket layer ends also facilitates air sealing the horizontal marriage joint at floor-to-floor wall connections.
At wall top plates, it is also advantageous to let in strips of air-sealing membrane to the airtight layer of each wall during wall construction, to be connected to the roof airtight layer during assembly, to complete the airtight layer. As well, holding blanket layer top plates slightly lower than the roof slope is beneficial to allow for discrepancies in construction.
During a typical installation like that shown in FIG. 13 where a panelized wall section is installed above another such section, typically (but not limited to) second story cave walls, the structural wall bears on top of the floor framing, but the blanket layer extends down below the top of the second floor. The second sheathing layer 11 may extend down to meet the (typically) first floor airtight layer allowing a small construction gap, and the joint is sealed with tape. The blanket layer does not extend down as far, typically leaving a 6-8″ horizontal gap to be filled with cellulose on site after air sealing is complete.
At gable walls, the panelized wall structures in accordance with the present invention may advantageously also provide for “balloon framing” of the structural wall either to span from the bottom of the first floor to the ceiling of the second floor or alternatively extending the framing to the top of the roof slope. “Balloon framing” the entire wall assembly is also possible by running structural components and blanket layer structure the full height of the building. It is also possible to install and seal blocking in the stud bays, in line with the ceiling air barrier, to allow continuity of the air barrier between ceiling and walls.
While panelized wall sections have thus been described in detail with regard to several configurations within a building, it should further be noted that the present inventive concepts may also be provided to a panelized roof section. Accordingly, FIGS. 14 through 18 relate to the present invention in regard to specifics of roofing configurations. Again, like elements as previously described are shown and labeled, though not discussed again as their structure and function are as previously explained herein above.
With specific reference to FIG. 14, there is shown a schematic cross-sectional view through a panelized roof section incorporating the present invention. Just as in the panelized wall section of FIG. 2 et seq., the panelized roof section also includes elements which can be grouped into five (5) basic categories which include the structural layer, the airtight layer, the blanket layer, the weather resistant barrier, and the rain screen.
The structural layer of the panelized roof section shown in FIG. 14 includes rafters 71 which are preferably suitable 2×10 SPF studs arranged 24-inch on center, in a commonly understood manner, ceiling strapping 64 from 1×3 SPF is arranged 16-inch on center upon which internal surfacing of gypsum sheetrock 33 or any suitable interior surfacing product for the given implementation is affixed. Within the voids between rafters 71, there is also provided mineral wool insulation 32. The interior framing system of rafters 71 carries all structural loads. Connection of the roof airtight layer to the wall airtight layer may be accomplished with flaps of second sheathing layer 11 that project below the rafters 71.
The airtight layer provides a structural diaphragm that is also the primary air barrier and vapor retarder on the outside of the structural layer. In terms of FIG. 14, this is provided by root sheathing 70. The root sheathing 70 is preferably constructed of a suitable weathertight coated OSB (oriented strand board) such as ⅝-inch ZIP® sheathing and rendered airtight with all joints and nail holes taped with a suitable weatherproof taping 50 such as Tescon Vana® adhesive tape with fleece backing available from Pro Clima® or any suitable weathertight tape.
In terms of FIG. 14, the blanket layer is the insulating layer located exterior to the roof sheathing 70 and which includes roofing I-joists 69 filled there between with cellulose insulation 14 or similar suitable insulating material. Each roofing I-joist 69 is preferably a 16-inch I-joist arranged 24 inches on center with SPF flanges and OSB webs. The blanket layer is structurally screwed (using structural screws) to the structural layer as shown with taping 50 provided to render any corresponding holes airtight as previously mentioned. It should be understood that sheet goods (plywood or OSB) are provided at the top and bottom of the I-joists as top and bottom plates so as to create a cavity for blown insulation. For purposes allowing air evacuation when installing blown insulation, holes may be drilled in the roofing I-joists 69 of the blanket layer and covered with air-permeable mesh. Cellulose insulation may be installed more densely than normal, at 4.0 to 4.25 pounds per cubic foot, to ensure that such insulation remains in place during transport and for the life of the building.
With continued reference to FIG. 14, the weather resistant barrier is formed by the second sheathing layer 11 which, similar to its use in the panelized wall sections, is made of an airtight, water-repelling, vapor-open fabric that is resistant to outdoor weather. It is advantageous that the placement of the second sheathing layer 11 is in a protected location, above the rafters, internal to the roof assembly.
The panelized roof section shown in FIG. 14 also includes a rain screen which includes the outermost parts shown adjacent the exterior of the second sheathing layer 11. Vertical roof strapping 68 is first suitably secured (e.g., via screws not shown) over the second sheathing layer 11 and preferably formed by 1×3 SPF arranged 24″ on center to abut each roofing I-Joist 69 as shown. Upon the vertical roof strapping 68 is secured horizontal roof strapping 66 preferably formed by 2×4 SPF purlins arranged 12″ on center so as to create a freely draining ventilation channel. The final outer layer of roofing 67 is provided in any typical manner such as standard sheet metal rooting or as desired for the given building's exterior decor requirements. Installation of roof strapping below the air barrier may be provided in a manner thick enough to allow electrical conductors to be installed while meeting code distance for fasteners.
Panelized roof sections may be pre-insulated at the factory or post Insulated at the installation site. Leaving the ratter bays uninsulated, as a “service cavity,” until after the building envelope is complete is beneficial so as to facilitate panel attachments, mechanical and electrical work. Panelized roof sections that are post-insulated may be provided in the form of prefabricated trusses that are installed, air sealed, and insulated on site, and may include structural support in the form of shop-fabricated roof trusses, air sealing in the form of a membrane below the trusses connected to the walls' airtight layer, and insulation blown into the resulting attic cavity.
FIG. 15 is a schematic cross-sectional cave view through a panelized roof section in conjunction with a panelized wall section, each incorporating the present invention. Here, the interface of the panelized roof section with the panelized wall section is configured so as to ensure that the airtight layer is contiguous and completely uninterrupted. More specifically, the end of the panelized roof section is angled to provide desired pitch of roofing 67. It should be noted that the wall rain screen cavity is connected with the roof ventilation plane for fully ventilated cladding.
A roofing rimboard 73 preferably formed of 1⅛″ OSB suitably wrapped with a weathertight tape. The roofing rimboard 73 abuts the first sheathing layer 30 with all joints including taping 50. As well, the airtight layer of the panelized wall section and the airtight layer of the panelized roof section include a barrier 72 there between. The barrier 72 is preferably a high performance airtight vapor control layer such as Pro Clima® DA, Intello, or Intello Plus vapor retarder layers with all joints sealed by taping 50 preferably with Tescon Vana® or Rapid Cell® tape at all seams and staples so as to provide a continuous air barrier. In this configuration, the airtight layer is formed contiguously by the roof sheathing 70, rimboard 73, barrier 72, and first sheathing layer 30, and assured by taping 50.
When there are cave overhangs, it is advantageous to hold the cave wall blanket layer top plates slightly lower than the bottom of the truss top chord so as to allow the top chord to extend over the top of the blanket layer. At cave walls and rake walls, running the blanket layer vertically beyond the structural wall top plate to meet (with a small construction gap) the roof plane may be accomplished for the beneficial purpose of over-insulating the roof framing.
FIG. 16 is a schematic cross-sectional view through panelized roof sections (one in dotted line not labeled) showing ridge detail and incorporating the present invention. Here, the panelized roof sections attach to a ridge beam 75 using rafter hangars 74. The interface between panelized roof sections atop the ridge beam 75 is seen to include a gap which is filled with insulation 48 which may be in the form of water cured butyl fired urethane foam which may be injected into the corresponding space. Taping 50 over the ends of abutting roof sheathing 70 ensures a contiguous airtight layer. The interface of the blanket layers includes a vertical gap in line with the ridge beam 75 and insulation 48, and which vertical gap is filled with cellulose insulation 14.
It is advantageous where two roof panels meet to build one panel with extra second sheathing layer 11 so as to be unfurled and sealed to the adjacent panel after air sealing is complete. It is also advantageous where two roof panels meet at the ridge to leave a cavity in the blanket layer to facilitate air sealing from above and/or to build one panel with extra second sheathing layer 11 so as to be unfurled and sealed to the opposite panel after air sealing is complete.
FIG. 17 is similar to FIG. 15 except that FIG. 17 includes a trussed roof. It should be readily apparent that the trussed roof includes trusses 76 that may be of any suitable design configuration corresponding to the given building requirements. Here, the airtight layer is provided by way of membrane 72 secured across the bottom of the given trusses 76 with taping 50 provided at all seams and staples. Heavy ceiling strapping 77 is then attached (e.g., via screws) to trusses 76 with the membrane 72 secured there between. In this configuration, the airtight layer is formed contiguously by the membrane 72 and first sheathing layer 30, and assured by taping 50.
A 24″ raised heel truss roof is typically a cost effective approach for a trussed roof design, insulated with loose-fill cellulose to a depth of 24″ to 30″ for U values ranging from 0.071 to 0.045 W/m2K (0.0125 to 0.008 Btu/hr ft2 ° F.). ≈R 80 to 120. The truss may be shaped like a conventional gable, or it may be a mono-pitch (aka “shed roof”), low-slope (aka “flat roof”), or other shapes. The economical choice is for the truss to have a horizontal bottom chord, resulting in a conventional flat ceiling, but it may also be scissor or parallel chord trusses to create cathedral ceilings.
FIG. 18 is a schematic cross-sectional view through a low slope pitch roof incorporating the present invention. Such a low slope, or flat, roof may include layers having roof sheathing 78 such as ZIP System®, fiber board 79, and EPDM (ethylene propylene diene monomer (M-class) rubber) 80 with suitable seam tape 81, drip edge 82, and fascia 83 which are known in the low slope roofing art to provide a suitably durable low slop roofing surface. In this configuration, a panelized roof section simply abuts to a panelized wall section and rests on top plate 65 of the internal wall 34. In this configuration, the airtight layer is formed contiguously by the roof sheathing 70 and first sheathing layer 30, and may also be assured by taping 50 over abutting ends so as to ensure a contiguous airtight layer.
The wall assembly and corresponding system is certified by the International Passive House Institute to be free of thermal bridging, with a U-wall of 0.101 W/m2K (0.017 Btu/hr ft2 ° F.), ≈R 58.6. The related detailing the building's exterior corners result in negative Psi (ψ) values, meaning that not only are they free of thermal bridging, they are a net gain when performing heat loss calculations. The present invention has a ψ at building exterior corners is −0.068 W/mK (−0.039 Btu/h ft2 ° F.) and at building interior corners the ψ value is 0.026 W/mK (0.015 Btu/h ft2 ° F.). The International Passive House Institute has also determined the panelized roof sections to perform with a U value of 0.065 W/m2K (0.011 Btu/hr ft2 ° F.), ≈R 90. At the cave connection with the exterior wall, typically a thermal bridge, the inventive roof assembly has negative thermal bridging: ψ=−0.029 W/mK. At the ridge, another potential source of problems, the marriage joint achieves ψ=−0.029 W/mK
As mentioned, the inventive panel assemblies (i.e., panelized wall structures and panelized roof structures) are shop-fabricated. In other words, the inventive assemblies are assembled primarily in a climate controlled facility which ensures high quality in construction and enables tight tolerances of all assembly dimensions. Panel size for each assembly is of course dictated by the given project's geometry, equipment constraints, and trucking restrictions. Following installation on site, each of the airtight layer, the blanket layer insulation, and the weather resistant barrier is completed at the marriage joints. Use of a crane may facilitate panel setting, while shipping of the panels may be provided horizontally on a trailer. It may be preferable to utilize waler boards (i.e., framing lumber attached to stakes in the ground) outside the building to brace wall panels as they are erected, as opposed to typical interior wall bracing which also advantageously protects the concrete slab from damage.
With further reference to FIG. 2, it should also be noted that the foundation insulation 20, 24 and corresponding slab 25 may provide unique innovations in the combination as shown. More specifically, a raft slab foundation that is a well-insulated, self-forming foundation system may be provided that includes EPS foam, in customizable interlocking shapes, to form the perimeter and “frost wing” (i.e., the portion which extends beyond the concrete slab). The customizable interlocking shapes may interlock with the frost wing to create a perimeter form for the concrete slab. As well, the EPS foam may be provided in simple rectangular form to create sub-slab insulation.
The foam components are prefabricated in a shop. Following site preparation, the foam components are set on the site, sealed together with sprayed foam, the vapor barrier is installed, concrete reinforcing is installed, and the concrete slab is poured into the EPS foam “raft.” At a nominal 8″, the concrete slab is thick enough that additional structural support in the form of footings is not typically required. Moreover, the foam insulation protects the slab from thermal losses. Such innovative raft slab foundations may beneficially provide features including the use of borate-treated EPS foam for all components and the use of different densities of EPS for different locations.
The shape of a “frost wing” portion of such a raft slab system may involve including a wing projecting beyond the building with a groove which receives the slab form and sloped to shed water. The shape of the “slab form,” L-shaped in section, which interlocks with the frost wing advantageously creates an 8″ tall form for the concrete slab. The raft slab system may feature: infilling the frost wing perimeter with rectangular blocks of borate-treated EPS foam; specific dimensioning of all parts; using component dimensions adequate to meet the Passive House standard in cold climates; having all parts cut to shape and length, including mitered wings at inside and outside corners; leaving gaps between all components, pending application of spray foam adhesive sealant; using spray foam adhesive sealant to connect all components; using blocks of foam offcuts to support steel reinforcing before the concrete slab is poured; following the concrete pour, wrapping the vapor barrier membrane onto the top surface of the concrete and sealing it with tape so as to be later connected with the wall air barrier; and backfilling over the frost wing with soil for protection and aesthetic reasons.
Still further, assemblies in accordance with the present invention may form a pier foundation that minimizes or eliminates the use of plastic foam and concrete, as both products have certain negative environmental impacts. A pier foundation utilizing helical metal piles or other forms of support, depending on various conditions, sized per building code and industry best practices may therefore benefit from the present panelized wall and roof structures. Above the piers, panelizing construction of the floor system may be provided in accordance with the same principles and features shown and described herein above with regard to the inventive panelized wall and roof structures.
As mentioned, for projects where treading lightly on the land is a key concern, eliminating plastic foam is a goal, or access to the site is compromised, a pier foundation may be used. Using helical piers—galvanized metal posts with an auger screw at the bottom, literally drilled into the ground—minimizes disturbance of the site. The floor is framed with deep I-joists and filled with dense-packed cellulose, with an airtight, moisture-repelling skin applied to the bottom of the floor system. A small, insulated chase may be used to bring utilities into a central location. The same insulated floor system used for piers may be used on an uninsulated foundation or crawlspace. The present invention utilized with a foam-free framed floor system uses 24″ I-joists filled with dense-packed cellulose, with assembly insulation values of 0.070 W/m2K (0.012 Btu/hr ft2 ° F.), ≈R 83.3.
It should be readily understood that the present invention advantageously allows in-shop fabrication of building components and assemblies thus ensuring quality control and fast, accurate installation on site. As well, this allows for configuring building components and assemblies for ease of loading and trucking flat (horizontally) on a flatbed trailer. Such in-shop fabrication of building components and assemblies thereby enable building envelope performance much greater than that provided by standard construction techniques.
The above-described embodiments of the present invention are intended to be examples only. Alterations, modifications and variations may be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.
Patent Application
20170030072
