Patent Grant
9016027
The following is a tabulation of some prior art that presently appears relevant:
This invention reveals a method of building insulated concrete walls by minimizing the freshly mixed concrete's hydrostatic pressure and using a special stud that supports and secures insulation boards used as stay-in-place forms. When used in this method, the insulation boards and stud substantially reduce the cost of an insulated, cast-in-place concrete wall.
Cast-in-place insulated concrete walls have become an important building feature and are built in a variety of ways. One method of building cast-in-place insulated concrete walls is to place insulation boards inside two concrete forms and cast concrete on one or both sides of the insulation board. The insulation boards are secured in the form's center or on one or both sides of the form after which concrete is cast into the form. During casting, the “wet” concrete produces a hydrostatic pressure on the forms that can reach up to two thousand pounds per sq. ft. of form area and must be counteracted with very strong forms and form ties. This makes forming concrete a costly process and placing insulation boards inside two forms does nothing to reduce these costs. Not only does the insulation board have added material costs, there are manufacturing and/or labor costs associated with the necessity of passing form ties through the insulation boards, inside the forms, such that the form ties connect the two forms to withstand the hydrostatic pressure.
Another method of using insulation boards to build cast-in-place insulated concrete walls is as stay-in-place, insulated concrete forms (ICF) which are used to replace conventional, removable forms. These ICF systems typically have two pieces of a foamed insulation board that provide two stay-in-place foam forms which are held together and spaced apart by connecting ties, webs or frames. These connecting ties, webs or frames counteract the hydrostatic pressure by holding the two foam forms together during the casting process. One feature of these systems is that the ties, webs or frames also provide a stud-like material to which wallboard may be attached.
However, all of the ICF systems are based on conventional casting of concrete, which produces high levels of hydrostatic pressure on the insulation board forms. To counteract this high pressure, numerous connecting ties, webs or frames are placed closely together—typically as close as 6 to 12 inches apart. This results in a large number of ties and frames that greatly increases both the material costs and the labor necessary to assemble these systems. While thicker insulation boards may be used to reduce the number of connecting ties or frames, any cost savings is offset by the higher cost of thicker foam boards. In addition, thick insulation boards would result in thicker walls which are undesirable for many structures.
The ICF systems also require specially shaped and fabricated foam board forms that work specifically with each company's special connecting tie, web or frame. When the costs of the special foam forms, the ties, webs or frames and the labor to assemble are added together, these systems become costly and only slightly less expensive than inserting insulation boards in conventional forms. In addition, the numerous ties, webs and frames and the block like foam forms of the ICF systems prohibits the use of wire mesh as an inexpensive concrete reinforcement and also make it difficult to place rebars. Finally, the ICF systems result with an insulation board as the face of the exterior side of the wall which requires additional work to prepare it for certain exterior wall claddings.
A third method of building cast-in-place insulated concrete walls is with so called 3D panels. These 3D panels have wire mesh embedded through and on both sides of an insulation board, to which concrete is pneumatically applied with shotcrete or gunite. Since pneumatically placed concrete has little or no hydrostatic pressure, the insulation boards may be relatively thin. The wire mesh acts to both reinforce the concrete and hold the two sides of concrete and the insulation board together. The end product is a concrete wall with insulation board sandwiched between two thin skins of concrete. While functional, these 3D panels have proved to be unpopular due to the high cost of the wire mesh encased foam panels and the fact most consumers do not want concrete as the finish for an interior wall. As such, the concrete on the interior side must be framed out and covered with a more desirable interior wallboard.
One prior art, U.S. Pat. No. 4,292,783, uses foam insulating slabs with separate sheets of wire mesh placed over these slabs, which are then sprayed with gunite to achieve a concrete wall. While less expensive than the 3D panels, this system also results in an undesirable concrete finish on the interior side of the wall which must be framed out and covered with a wallboard.
The present invention is a simple and low cost alternative to concrete forms, ICF and 3D panels used in building insulated, cast-in-place concrete walls. The low cost is achieved by using off-the-shelf insulation boards as one-sided forms for low hydrostatic pressure producing concrete. The lack of hydrostatic pressure enables the insulation board forms to be thin and require minimal bracing. Moreover, there are no form ties, webs or frames to connect two forms together. Special studs are used on the interior side only and may be spaced up to 24 inches apart. These studs are used to support and/or secure the insulation boards and to provide a solid base for the attachment of wallboards and wall hangings. This system also provides an open work area for placing inexpensive wire mesh and conventional rebars. The end result is an insulated, reinforced concrete wall with a concrete exterior, ready for any type of finish and an interior side with insulation board and studs ready for wiring and wallboards, all at a cost much less than other systems.
This invention is a method of building low cost insulated concrete walls by minimizing the freshly mixed concrete's hydrostatic pressure and using a special stud that supports and/or secures simple rectangular shaped insulation boards used as stay-in-place forms on one side of the wall. The construction process is simple beginning with the vertical positioning of the studs and insulation boards on one side of the wall and secured with minimal bracing. Steel reinforcement is placed next to the backside of the insulation boards and a low or no-slump concrete is placed against the reinforcement, the backside of the stud and the insulation board. The concrete's hydrostatic pressure is minimized or eliminated by either pneumatically spraying it or by using the concrete's thixotropic properties. The lack of hydrostatic pressure eliminates the need for a conventional form to support the insulation board and stud as well as the need for form ties, webs or frames used to hold forms together. As the concrete cures, it causes the stud to become a sturdy member, sufficient to secure the insulation board and wallboard that may be affixed to the stud. The insulation board used as a one-sided form requires only minimal bracing.
While the pneumatically sprayed concrete that can be used is well known in the art, placing methods based upon utilizing the thixotropic properties to reduce the hydrostatic pressure on the insulation board and stud is new art. Thixotropy is a material property that describes a material as being in a solid or semi-solid state when at rest and the ability to becoming liquefied when agitated. Thixotropy is a property of freshly mixed no-slump or low-slump concrete in that this type of concrete is in a semi-solid state, similar to moist, clumpy dirt, when at rest and becomes liquefied when vibrated. Since hydrostatic pressure is only present when a liquid state exists, limiting the amount of a liquid or semi-liquid concrete present at any one time will limit the amount of hydrostatic pressure present. Moreover, the liquefaction is temporary in that as soon as the vibration ceases, the concrete immediately reverts to its semi-solid state and stops exerting hydrostatic pressure.
Applicant has two copending applications wherein the thixotropic properties of low or no-slump concrete are used in the placement of the concrete. The first is a Vertical Vibrating Screed as disclosed in applicant's copending application Ser. No. 13/373,816 filed 1 Dec. 2011 and the second is copending application Ser. No. 13/374,839 filed 17 Jan. 2012 entitled the Thixotropic Concrete Forming System. Both of these copending applications are incorporated by reference.
An important aspect of this invention is the stud to which wallboard may be attached after the concrete cures. Most building codes require that wallboards be mechanically attached to the wall and the stud provides a solid member to facilitate such attachment as well as support wall hangings. The stud also acts to secure the insulation board from weather before casting and from the concrete cast and liquefied against the insulation board. The stud also eliminates the need to separately frame the insulation board side of the wall to facilitate attaching wallboard or similar wall cladding.
In the preferred embodiment of this invention, the stud and insulation board comprise a stay-in-place form that remains in position after the concrete is cured and provides insulating features to the structure. The insulation board may be made of any rigid material and is generally rectangular in shape.
In the one embodiment of this invention the studs are specially shaped with a generally flat flange section to which a generally perpendicular tail is attached. The tail may be of any length that extends beyond the backside of the insulation board and into the cavity where the concrete is to be cast. The tail also has a means for embedding into the fresh concrete as it is cast and liquefied and thereafter bonds to the concrete as it hardens. The flange section of the stud provides a rigid member to which wallboard may be attached. The studs may be made of any material which is sufficiently rigid or is made sufficiently rigid as the concrete hardens so as to enable wallboard to be attached to the stud.
In another embodiment braces hold the stud and/or the insulation boards in place both before and during concrete casting. Once the concrete hardens, the insulation boards are sandwiched between the flange or cross member of the stud and the hardened concrete.
In another embodiment of the invention, the studs have a cross member that may extend the entire length on a full length tail such that a channel is formed between the cross member and the stud's flange. When an insulation board is placed in this channel, it forms a seal to prevent water intrusion from one side of the insulation board to the other side.
In another embodiment of this invention the studs are configured to have a flange on both sides of the wall to which wallboard or other claddings may be attached.
This invention is a method of building low cost insulated concrete walls by minimizing the hydrostatic pressure of the freshly mixed concrete and using a special stud that supports and/or secures simple rectangular shaped insulation boards used as forms on one side of the wall.
The stud 3 of this invention has one or more flanges 1, one or more tails 2, one or more end of tails 14 and a means for bonding the stud to the concrete. The stud 3 may also have a means for securing the insulation board to the stud.
The tail 2 of the stud 3 may also have bonding holes 7 and pin holes 13 punched into the tail 2 as shown in a side view of the stud 3 in
It is important to note that the insulation boards 8 and the studs 3 are simply positioned together, stood vertically and braced. As such, the insulation boards 8 and the studs 3 comprise a stay-in-place form 16 which is defined as a form in and of itself and does not use other forms for bracing. As a stay-in-place form 16 the insulation boards 8 and studs 3 are only braced by commonly used horizontal and vertical bracing well known in the art. In this configuration the flange 1 of the stud 3 is on the front side 12 of the insulation board 8 and the tail 2 extends through the backside 10. The freshly mixed no-slump concrete is then placed on the backside 10 of the insulation boards 8 using a process that greatly reduces the hydrostatic pressure that is typically present in wet concrete. It is the significant reduction in the concrete's hydrostatic pressure that enables the insulation boards 8 and studs 3 to be used as stay-in-place forms 16.
The reduction of the hydrostatic pressure may be accomplished by pneumatically spraying the concrete or by a new process that uses the thixotropic properties of no-slump concrete during its placement (for purposes of this invention, the term “no-slump” concrete shall include “low slump” concrete).
Pneumatically spraying the concrete is commonly known as gunite for a dry concrete mixture and shotcrete for a wet concrete mixture. Both of these pneumatically applied methods are well known in the art and have been used for more than 40 years. In both of these pneumatically applied processes, the concrete is sprayed against the stay-in-place form 16 comprised of the insulation boards 8 and stud 3. After the desired concrete thickness is reached, the excess concrete is struck off and the concrete may be left rough or may be finished to the desired appearance.
The new process of reducing the concrete's hydrostatic pressure uses the thixotropic properties of no-slump concrete. Thixotropy is a material property that describes a material as being in a solid or semi-solid state when at rest and becoming liquefied when agitated. Freshly mixed no-slump concrete is a highly thixotropy material in that the concrete is in a semi-solid state when at rest and becomes liquefied when vibrated. Since hydrostatic pressure is only present when a liquid state exists, limiting the amount of a liquid or semi-liquid concrete present at any one time will limit the amount of hydrostatic pressure present. Moreover, the liquefaction is temporary in that as soon as the vibration ceases, the concrete immediately reverts to its semi-solid state and stops exerting hydrostatic pressure.
When placing freshly mixed no-slump concrete it is initially at rest and in its semi-solid state while being cast into the casting area 15 and thereby is exerting little or no hydrostatic pressure. However, as soon as the concrete is vibrated during the placement process it becomes a semi-liquid exerting hydrostatic pressure and is temporarily liquefied to the point that it is able to flow to fill the casting area, encase the embedments and become consolidated. Importantly, when the vibration ceases, the no-slump concrete immediately reverts to its semi-solid state and stops exerting hydrostatic pressure. Therefore, the hydrostatic pressure can be significantly reduced by using no-slump concrete and minimizing the amount of concrete being liquefied (vibrated) at any one time. This results in the ability to use relatively weak insulation boards 8 and studs 3 as stay-in-place forms 16 on one side of the wall without support from other forms, form ties or frame connections to a second form.
As used herein, the terms place, placing or placement when used regarding concrete, refers to the process of casting, vibrating and the flowing, i.e. distribution of the concrete.
The means for placing temporarily liquefied no-slump concrete is based upon the above described process of reducing the hydrostatic pressure and specifically include the disclosures contained in two copending applications. The first copending application is a Vertical Vibrating Screed disclosed in application Ser. No. 13/373,816 filed Dec. 1, 2011 and the second is copending application Ser. No. 13/374,839 filed Jan. 17, 2012 entitled the Thixotropic Concrete Forming System. Both of these copending applications are incorporated by reference and are two means for placing a temporarily liquefied no-slump concrete.
The means for placing temporarily liquefied no-slump concrete using the Thixotropic Concrete Forming System copending application uses a tall form-short form combination set of concrete forms comprised of at least one tall form side of vertically faced forms erected to the full height that is to be monolithically placed and at least one short form side comprised of erecting multiple levels of vertically faced short forms stacked above one another with each level filled with concrete, vibrated, consolidated and integrated in a horizontal progression before the next level is erected and repeating this process to the full height of the monolithically placed structure.
The means for placing temporarily liquefied no-slump concrete using the Vertical Vibrating Screed copending application is described as: (a) positioning a vertically oriented backstop on at least one side of a vertical structure to be cast and then positioning a vertically oriented screed a predetermined space apart from the backstop and the screed has a face facing the backstop; (b) casting a highly thixotropic cementicious material into a hopper attached to the screed and the hopper feeds the material into a casting area between the face and the backstop where the material is liquefied, consolidated and spread in the casting area; (c) as the screed moves in a vertical direction, it shapes the outside face of the material with the screed and a trailing slip form; (d) eliminating the seams between the material placed in a present pass with the material placed in any previous adjacent pass with a seam form which is a lateral extension to the screed and that overlaps the seam; (e) the screed is supported and guided in a predetermined direction while maintaining a predetermined distance from the backstop to complete a pass; and (f) the above steps are repeated for any successive pass until a wall, column or other vertical structure are cast.
The stud 3 may be made of plastic, metal, wood or other materials or a combination of materials and may be extruded, molded or otherwise shaped or assembled. There may also be a variation in the shape and configuration of the stud 3 to include having multiple flanges 1, tails 2 and end of tails 14. For example
The stud 3 may be used by itself or in conjunction with perimeter members 20.
The tall form-short form combination is comprised of form boards that may be of any size and may have a rectangular or irregularly shaped form face that may be multi-directional, horizontally or vertically oriented. The form boards may be removable or stay-in-place and made of any material including foam, wood, plastic, metal, paper, cardboard, glass, ceramic, brick, stone or a composite. As such, the form boards include finished claddings that may be used as form boards, adhere to the concrete and stay-in-place after casting. The form boards may also be used to support forms liners.
Also in
In
The perimeter member 20 may also be attached to the slab or foundation or other floor or to headers, columns or beams and other such structural members present in the building (not shown).
A top of wall backstop may be screwed to the top perimeter member and overhang the area into which the concrete is to be placed. This top board (not shown) acts as a backstop or form for the top of the wall when concrete is sprayed against the top form board. After the concrete is cured, the top form board may be removed or it may remain in place and provide a means for attaching trusses to the wall. The top form board may also provide a straight edge on which the sprayed concrete may be struck along the length of the wall.
While
The stud of this invention may also be of different shapes and configurations as shown in the following examples.
Two inverted “L” shaped studs may be used for inside corners or a single “Y” shaped stud may be used (not shown). Outside corners may be studded with an arrow shaped stud that has two flanges at a right angle to each other and a single tail that extends to the concrete.
Another embodiment of this invention are configurations that provide a means for positioning a second flange on the wall's second side in order to permit wallboard, siding, paneling or similar wall claddings to be attached to the flanges on both sides of the concrete wall. A flange on the concrete side of the wall also provides a strike-off surface to facilitate striking off the excess concrete when pneumatically sprayed concrete is used.
As shown in
The insulation boards may be rectangular shaped and placed in the same plain as shown in a top view of
The insulation boards of this invention may be cut into certain widths that are separated by the studs of this invention or the insulation boards may be connected together by a tongue and groove or a “U” shaped interlocking feature. If the insulation boards are connected together, the studs and tails are punched through the insulation boards at the desired locations as revealed in
From the description above, a number of advantages of some embodiments of my method of building insulated concrete walls become evident:
This application is a continuation-in-part of application Ser. No. 12/932,657 filed Mar. 2, 2011 which claims the benefit of the filing date of provisional application Nos. 61/339,330 filed Mar. 3, 2010. This application claims the benefit of copending application Ser. No. 13/374,839 filed Jan. 17, 2012 claiming the benefit of the filing date of provisional application Nos. 61/461,437 filed Jan. 18, 2011 and 61/462,463 filed Feb. 3, 2011. This application claims the benefit of copending application Ser. No. 13/373,816 filed Dec. 1, 2011 claiming the benefit of the filing date of provisional application Nos. 61/458,934 filed Dec. 3, 2010 and 61/461,436 filed Jan. 18, 2011. All the above cited applications are incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
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| Child | 12932657 | US | |
| Parent | 13373816 | Dec 2011 | US |
| Child | 13374839 | US |
