STRUCTURAL THERMAL BREAK

Abstract

A load-bearing thermal break construction element for use in buildings, particularly with overhangs or extensions projecting from the exterior building envelope, comprises a concrete and insulation-filled shell with rebar extending therethrough. The shell has an interior space and a plurality of shafts extending through the interior space. The shafts are shaped to receive rebar in an interference fit, and may be shaped to permit the rebar to pivot while retained in place in the shell. The interior of the shell is filled with insulation and concrete prior to installation in a building.

Description

TECHNICAL FIELD

This disclosure relates to a thermal break for use in construction.

TECHNICAL BACKGROUND

In buildings with overhangs or extensions, such as canopies and balconies, heat transfer from the interior to the exterior (or vice versa) can occur due to the heat conductivity of the construction materials because the structural elements supporting the overhang or extension penetrate the building envelope and are typically highly thermally conductive. Consequently, it is desirable to thermally isolate the overhang or extension to minimize heat transfer between the interior and exterior, to improve building heating or cooling efficiency. In fact, building regulations may require that the thermal conductivity of such supporting structures be broken by interrupting the path of heat conduction. At the same time, the thermal break must provide the required strength and stiffness at the connection.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate by way of example only embodiments of the present invention,

FIG. 1 is a front perspective view of a shell of an example thermal break of the invention.

FIG. 2 is a rear perspective view of the shell of FIG. 1.

FIG. 3 is a top view of the shell of FIG. 1.

FIG. 4 is a back view of the shell of FIG. 1.

FIG. 5 is a cross-sectional view of the shell of FIG. 1, taken along the plane A-A indicated in FIG. 4.

FIG. 6 is a flowchart setting out steps in an example method of assembling and installing the thermal break.

FIG. 7 is a rear perspective view of partial assembly of a variant of the thermal break using the shell of FIG. 1.

FIG. 8 is a side view of the thermal break of FIG. 7 installed in a building structure.

DETAILED DESCRIPTION

The present disclosure provides a load-bearing thermal break construction element for use in constructing buildings, in particular those with overhangs or extensions projecting from the exterior building envelope. The body of the thermal break comprises concrete encasing insulating material. The concrete, in turn, is encased in a shell with reinforcing bars (rebar) passing perpendicularly through shafts that receive and retain the rebar in place. The slab concrete protruding into the shaft provides additional shear strength. The shell defines the shape of the thermal break, including shear lugs to provide structural support to the overhang or extension. The thermal break is easy to manufacture, unlike certain prior art thermal breaks requiring special manufacturing steps such as bending rebar or special materials.

FIGS. 1-5 depict an example shell 10 for use in manufacturing the thermal break. The shell 10 functions as both a retention means for rebar and a mold to retain the concrete and insulating material. The shell 10 includes shafts 40, 50 for receiving and retaining lengths of rebar (not shown in FIGS. 1-5). FIG. 1 provides a front perspective view of the shell 10. In the particular example illustrated in the drawings, the shell 10 comprises a top 12, a bottom wall 14, side walls 16, and first and second walls, referred to here as the front and back walls 20, 30. The walls 14, 16, 20 and 30 together define an interior space 60. Labels such as “top”, “upper”, “bottom”, “lower”, “side”, “front”, and “rear” or “back” are used with reference to the illustrated embodiment for convenience, to distinguish different features of the example shell 10 depicted in the drawings, but are not intended to be limiting. In the example shown in the drawings, the front wall 20, as it is referred to herein, would face the interior of the building and the rear wall 30 would face the exterior. A number of tunnels or shafts 40, 50 are formed in the shell 10, defining passages for rebar perpendicular to the length of the shell 10. The top 12 of the shell 10 may be left entirely open to receive poured concrete, but may be partially closed in other implementations.

The thermal break comprises at least one series of rebar, generally aligned at the same height in the thermal break. Depending on the requirements of the building and the dimensions of the thermal break, the thermal break may comprise two series, or even more series, of rebar. In the illustrated example, the shell 10 accommodates two series of rebar in an upper series of shafts 40 and a lower series of shafts 50. Each of these series is arranged longitudinally along the body of the shell 10.

Referring first to the first series of shafts 40, each shaft extends between a port or aperture 42 in the front wall 20 and a port or aperture 48 in the rear wall 30. As can be seen in the drawings, in this example the shafts 40 are generally circular in cross-section but vary in dimension across the width of the shell 10. The front shaft wall 44 tapers from an initial diameter at the front port 42 gradually inward towards the midsection of the interior space 60; similarly, the rear shaft wall 46 tapers from an initial diameter at the back port 48 gradually inward towards the midsection. At the midsection, the walls 44, 46 taper more abruptly to a smaller diameter waist 45, which is sized to accommodate rebar with an interference fit.

The second series of lower shafts 50, if included, may be similarly shaped and positioned at a different height of the shell 10. In the illustrated example, an alternative shaft profile is shown. The lower series of shafts 50 extend across a lower portion of the shell 10 between the front wall 20 and rear wall 30. Again, these shafts 50 are generally circular in cross-section, tapering from the front and rear wall 20, 30 towards the midsection in the interior space 60. Each of the front and rear wall 54, 56 of each shaft 50 tapers inwardly from the towards the waist 55 of the shaft 50, which again is sized to receive and retain rebar in an interference fit.

In the illustrated example, both the upper and lower shafts 40, 50 effectively have a symmetric hourglass design. In other implementations, the front and rear portions of the shafts may be shaped differently. The spacing of the shafts 40 or 50 will depend on the intended use of the thermal break, as well as any legal requirements or standards that apply to the building construction. As those skilled in the art will understand, generally it is expected that the rebar of the thermal break, and thus the shafts 40 or 50, will be spaced to match the rebar in the concrete slab (e.g., the overhang or extension) to facilitate installation, since the rebar of the thermal break can be more easily tied to the slab rebar on each side.

The front and rear walls 20, 30 also include projecting portions. As can be seen in FIGS. 1 and 2, the front wall 20 includes projections 24, 28 extending longitudinally along the body of the shell 10. The first projection 24 is located at the midportion of the wall 20, and the second projection 28 provides a lip at the top of the front wall 20. The back wall 30 includes projections 32, 36 extending longitudinally along the body of the shell. The first projection 32 is located at the bottom of the shell 10, and the second projection 36 is located at the midportion of the wall 30, approximately (but not necessarily) at the same height as the first projection on the front wall 20. In construction, the projections 24, 28, 32, 36 function as shear locks or lugs that help prevent slippage of the slab against the thermal break. Additionally, the enlarged diameters of the shafts 40 at the front and rear walls 20, 30 permit poured concrete to surround the rebar emerging from the shell 10.

The shell may be formed of any suitable material, such as blow-molded polyethylene terephthalate (PET). The dimensions of the shell 10 may be determined according to the intended application and use of the thermal break. The length of the shell 10 may be consistent with standard thermal break lengths currently used in construction (e.g., 1 m). The height of the shell 10 may correspond to the depth of the slab with which the thermal break will be used. Typical heights may range from 160 to 300 mm. In the illustrated example, the shell 10 width (excluding projections 24, 28, 32, 36) is about 77.8 mm; projections 24, 28, 32, 36 extend about 12.7 mm beyond the shell width. The projections 24, 36 may be about 46 mm in width, while the projections 24, 32 at the top and bottom of the shell 10, respectively, may be thinner with a width of about 15 to 20 mm. The wall thickness of the shell 10 is sufficient to withstand pressure when the shell 10 is filled with concrete; in this example, the wall thickness is about 0.76 mm. Edges of the shell may be chamfered.

FIG. 6 outlines steps of the manufacture of the thermal break using the shell 10. As a first step 200, the shell 10 is provided. Next, at 210, pieces of rebar are inserted in the shafts 40 and/or 50 of the shell 10. As noted above, the rebar is effectively fixed in place in the shafts 40 and/or 50. The tapered profile of the shaft walls 44, 46, 54, 56 permits one or more of the rebar to be positioned at an oblique angle to the shell 10 while still being retained by the interference fit with the waist 45, 54. Thus, while the rebar is fixed against sliding to preserve the required lap length, it may be pivoted as needed during installation of the thermal break. For example, the rebar can be angled to be brought closer to the slab rebar to facilitate tie-in with the slab rebar. Insulation is then installed in the shell at 220. For example, pieces of insulation material may be inserted in the interior space 60. Once the insulation is in place, concrete is poured at 230 to fill the interior space 60 of the shell 10. The concrete will fill remaining voids in the shell 10, including the projections 24, 28, 32, 36. The concrete may then be allowed to cure prior to installation of the thermal break in a building structure at 240.

FIG. 7 depicts a further example of the thermal break, as well as the manufacture of the thermal break at an intermediate stage, prior to pouring concrete. As can be seen in this drawings, blocks of insulation 70 are inserted in the shell, generally between the shafts 40, 50, and each of the shafts 40, 50 holds a length of rebar 100. Some shafts 40, 50 may be left empty, since the building design may not require rebar 100 in every shaft. Any suitable insulation material, such as closed-cell extruded polystyrene foam (e.g., Styrofoam®), may be used. The selected insulation material, the shape and size of the inserted insulation 70, and the ratio of insulation 70 to concrete within the shell 10, depends on the desired R-Value and structural integrity of the thermal break. Use of insulation blocks or pieces permits assembly of the thermal break to be completed quickly; however, in alternative implementations, concrete may be poured in stages between insertions or applications of insulation.

The rebar may be common steel rebar, but in some embodiments, composite rebar such a glass fiber reinforced polymer (GFRP) rebar is employed. GFRP rebar offers greater corrosion resistance to steel rebar, which is desirable in outdoor structures, as well as lower thermal conductivity than steel. The concrete poured into the shell 10 may be any suitable concrete, and in some implementations may be basalt or carbon fiber-reinforced concrete.

In this embodiment, the thermal break includes a shield member 80, a panel projecting away from the upper surface of the shell 10, to block water penetration from the exterior. The shield member 80 may be formed of plastic, and may be attached to the thermal break using any suitable means. For example, it may be fastened to the shell 10, or embedded in the concrete once it is poured. FIG. 8 shows the complete thermal break in place in a building structure. The rebar 100 extends in either direction from the thermal break into the balcony or overhang 310, and the building interior slab 320. The shield member 80 extends upwards, and is fastened to the balcony door or other vertical component 300 by screws or other fasteners.

It should be understood that this description is not intended to be limiting, and that the examples contemplated herein include all alternatives, modifications, and equivalents as would be appreciated by the person skilled in the art, and are included within the scope of the accompanying claims. Although the features and elements of various examples or embodiments may be described as being in particular combinations, the person of ordinary skill in the art will appreciate which features or elements can be used alone, without the other features and elements of the embodiments, or in various combinations with or without other features and elements disclosed herein. Further, individual features or variations described in respect of one example or embodiment in this disclosure can be used with other examples or embodiments mentioned herein, as would be understood by the person skilled in the art.

The examples and embodiments are presented only by way of example and are not meant to limit the scope of the subject matter described herein. Each example embodiment presented above may be combined, in whole or in part, with the other examples. Further, variations of these examples will be apparent to those in the art and are considered to be within the scope of the subject matter described herein. Some steps or acts in a process or method may be reordered or omitted, and features and aspects described in respect of one embodiment may be incorporated into other described embodiments.

A portion of the disclosure of this patent document contains material which is or may be subject to one or more of copyright, design patent, industrial design, or unregistered design protection. The rights holder has no objection to the reproduction of any such material as portrayed herein through facsimile reproduction of the patent document or patent disclosure, as it appears in the Patent Office file or records, but otherwise reserves all rights whatsoever.

Claims

1. A thermal break, comprising: a shell, comprising: an interior space defined by exterior walls; anda plurality of shafts extending through the interior space between a first wall and an opposing second wall of the exterior walls, the plurality of shafts shaped to receive and retain corresponding pieces of rebar;the corresponding pieces of rebar, retained in the plurality of shafts;the interior space being filled with concrete and insulation.

2. The thermal break of claim 1, wherein the shell further comprises at least one projection extending longitudinally along each of the first wall and the second wall to provide a shear lock.

3. The thermal break of claim 2, wherein the first wall comprises a projection at the bottom of the thermal break and the second wall comprises a projection at the top of the thermal break.

4. The thermal break of claim 3, wherein each of the first wall and the second wall each comprises a further projection located at midportion of the first wall and the second wall, respectively.

5. The thermal break of claim 1, wherein the plurality of shafts comprises a series of shafts arranged longitudinally.

6. The thermal break of claim 5, wherein the plurality of shafts comprises at least two series of shafts arranged longitudinally at different heights of the thermal break.

7. The thermal break of claim 1, wherein each shaft is defined by shaft walls tapering from initial diameters at the first wall and the second wall towards a smaller diameter waist sized to retain the rebar.

8. The thermal break of claim 1, wherein the shell further comprises a shield member projecting upward from an upper surface of the shell.

9. A shell for a thermal break, comprising: an interior space defined by exterior walls; anda plurality of shafts extending through the interior space between a first wall and an opposing second wall of the exterior walls, the plurality of shafts shaped to receive and retain corresponding pieces of rebar.

10. The shell of claim 9, wherein the shell further comprises at least one projection extending longitudinally along each of the first wall and the second wall to provide a shear lock.

11. The shell of claim 10, wherein the first wall comprises a projection at the bottom of the shell and the second wall comprises a projection at the top of the shell.

12. The shell of claim 11, wherein each of the first wall and the second wall each comprises a further projection located at midportion of the first wall and the second wall, respectively.

13. The shell of claim 9, wherein the plurality of shafts comprises a series of shafts arranged longitudinally.

14. The shell of claim 13, wherein the plurality of shafts comprises at least two series of shafts arranged longitudinally at different heights of the shell.

15. The shell of claim 9, wherein each shaft is defined by shaft walls tapering from initial diameters at the first wall and the second wall towards a smaller diameter waist sized to retain the rebar.

16. The shell of claim 9, further comprising a shield member projecting upward from an upper surface of the shell.

17. A method of manufacturing a thermal break, the method comprising: inserting rebar through shafts provided in a shell, the shafts extending between opposing walls of the shell through an interior space of the shell, such that the rebar extends through the shell and protrudes from either opposing wall;inserting insulation in the interior space of the shell; andfilling the interior space with concrete.

18. The method of claim 17, wherein the concrete completely submerges the insulation.

19. The method of claim 17, wherein the insulation is extruded foam.

20. The method of claim 17, wherein the concrete is basalt or carbon fiber reinforced concrete.