Internally Braced Insulated Wall and Method of Constructing Same
A high thermal resistant vertical wall on a base foundation in which stacked ICFs define an interior wall space that is filled with foam and concrete membranes coat the exteriors of the ICFs.
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The present invention relates to wall structures and methods of constructing same and, in particular, to wall structures having internal bracing during construction and superior thermal resistance.
Approximately 50% of the energy consumed in the operation of a building is used to maintain the temperature of the interior spaces. In the cold months, the energy is used for heating, while in the hotter months, the energy is used for cooling. Walls with exceptional thermal resistance, such as those of the present invention, have the potential to significantly reduce the operating energy of a building.
The present invention relates to systems and methods for constructing very high thermal resistivity (“R value”) building walls having interior and exterior membrane surfaces typically of concrete and applied under pressure.
One of the difficulties of constructing such walls is keeping them in place and plumb while they are being erected and while the membranes are being applied.
The prior art practice for keeping walls in place during construction is to use external bracing, primarily using wood or pipe members. The disadvantages of external bracing (regardless of the materials used) is that the bracing makes the application of the outer membrane difficult, requiring substantial effort and time, which translates directly into added expense. External bracing also consumes materials that are typically discarded. Even if some of the bracing materials are reused or recycled, they add nothing to the structural integrity of the wall after it is fully constructed.
U.S. Pat. No. 7,461,488 teaches an internal bracing system using straw bales. While that system has been successfully implemented and is an advance over the prior art, straw bales are inherently non-uniform in size, cumbersome to work with and at risk of attracting and retaining moisture. The present invention provides the advantages of internal bracing without the disadvantages accompanying straw bales and provides a much higher level of thermal resistivity and earthquake stability.
The present invention teaches a wall structure and method for its construction that can provide exceptionally high thermal resistivity and stability under earthquake conditions using internal bracing during construction that permits walls of 30 feet and more to be constructed with little or no external bracing. The ability to construct a wall of the present invention using only internal bracing eliminates the difficulties of applying the outer wall membrane and incorporates members that provide that bracing as internal structural elements of the finished wall.
BRIEF DESCRIPTION OF THE INVENTIONThe high thermal resistance wall of the present invention comprises a pair of generally parallel spaced apart concrete membranes connected by spars with insulated concrete forms (ICFs) having spaced apart ICF panels disposed adjacent to and between the membranes defining an internal wall space and insulating foam filling the internal wall space. In addition, internal bracing structures disposed in the internal wall space during construction remain as structural elements of the finished wall.
The method of constructing the wall comprises: stacking spaced apart ICF panels onto the foundation base wherein each panel has an interior surface and an exterior surface where the interior surfaces define an internal wall space; securing a plurality of bracing ladders at spaced apart locations on the base foundation in the internal wall space adjacent the ICFs; disposing a plurality of spar members across the internal wall space and through the ICF panels; filling the internal wall space with insulating foam; and applying a concrete membrane onto the exterior surfaces of the ICF panels to a thickness that covers portions of the spar members. In a preferred embodiment, the membranes are only applied after the entire wall is otherwise constructed.
The invention achieves its outstanding results by the strategic placement (both vertically and horizontally) and interconnection of a plurality of ladder structures (truss-like members) and various spar members. The ladder structures give the walls sufficient out-of-plane strength to remain erect and plumb during construction both before the outer membrane is applied and while the outer membrane is applied.
The present invention permits the membranes to be applied without the need to work around external bracing, greatly simplifying that process.
It follows, of course, that erecting and dismantling external bracing is eliminated, as are the substantial costs and waste associated therewith.
One of the outstanding features of the present invention is that a wall of any height (from 8 feet to 35 feet or more) can be assembled from small parts that are easily transported to the site. Spars and rebar members are tied or tack welded to form a stiff truss-like system that stabilizes the wall during and after construction.
Accordingly, it is an object of the present invention to provide internal bracing systems and methods for constructing a high R-value wall. It is another object of the present invention to provide internal bracing and methods for constructing a high R-value wall to a height of 35 feet or more without the need for external bracing.
Yet another object of the present invention is to provide systems and methods for constructing a high R-value wall in which permanent internal structural elements act as bracing during construction.
The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings.
The following description includes some specific measurements for purposes of illustration only and, except where otherwise indicated, such specific measurements are not to be taken as limitations of the invention. While these dimensions will change for walls of different thicknesses and heights, what does not change is the functional relationship of the various structural members to one another.
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ICFs are used in prior art systems to form a cavity into which concrete is pumped to form the core structural element of a foundation or wall, with reinforcing steel (rebar) disposed between the panel members 14 before concrete placement to give the concrete flexural strength, similar to bridges and high-rise buildings made of concrete.
While there are a number of different brands and configurations of ICFs, those used in the present invention are those available brands that are stackable, constructed from a lightweight foam material and can be adjusted to vary the distance between panel members 14 to create interior wall spaces 18 of different widths 13W. As will be seen by what follows, ICFs 13 are not used in the present invention as concrete forms at all, but rather in a way and for a purpose that enables a novel wall structure to be built having the same or better load-bearing capabilities as a concrete core wall and superior thermal resistance and earthquake stability, as well as other advantages.
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U-shaped spar member 37 has a generally straight midsection 37a and end sections 37b at approximate right angles to midsection 37a. In its preferred embodiment, the spar 37 is a contiguous structure that spans the interior wall space at a location that disposes its end sections 37b outside of the ICFs 14 (outside of interior wall space 18) and around end sections 30 of cross spar members 28 and 32 (see
Because the spar members 28, 32, 37 and 38 span the interior wall space 18, they create a thermal conductivity path. Even when only two spar sets 33 are used in each location (see below), the amount of heat that can travel through these spar members is surprisingly high when the spars sets 33 are made of a high thermal conductance material such as steel rebar. The use of such high thermal conductivity materials can result in a significant amount of heat transfer and a concomitant reduction in the overall R-value of the wall. In order to prevent this degradation in the R-value, in a preferred embodiment of the invention, all of the spars that comprise spar sets 33 are formed from fiberglass, which is a low heat conductance material compared to steel. Using fiberglass in place of steel rebar has a dramatic reduction in heat transfer across the wall 11 without compromising structural performance.
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Unlike conventional concrete structures having a concrete core that has moderate thermal conductance, the core material of the wall 11 of the present invention is all insulating material (ICFs 13 and foam 53), both having very low thermal conductance.
Foam 53 is applied as a combination of liquids that expand when exposed to the air to fill all of space 18. Such foam systems are known in the building industry and are capable of producing foam in a range of densities. Gaco Western offers a liquid pour system: Low density, rigid polyurethane foam for cavity fill which uses as a Blowing Agent—245fa Enovate. Gaco's product designation is Polyfoam™ CF-200, which is a zero ozone depleting liquid pour system for general use in cavity fill applications. It is co-blown with HFC and water and cures to a low density rigid polyurethane closed cell foam. High density rigid polyurethane closed cell foam is also available. In either case, the closed cell structure of the foam 53 prevents the intrusion of water into the interior wall space 18 that could, if present, diminish the R-value of the wall. In the same way, foam 53 also prevents any insect infestation or other undesirable material from entering the space 18.
The method of the present invention for constructing a wall 11 of superior structural integrity and high thermal resistance (high R-Value) onto a base foundation 12 wherein vertically extending opposing pairs 17p of anchor dowels 17 are cast into and spaced apart along the length 12L of the base foundation 12, comprises:
(1) attaching to the base foundation 12 preassembled vertically oriented mid-wall bracing ladders 23 at spaced apart locations along the length 12L of base foundation 12;
(2) stacking a base run of ICFs 13 several panels 14 high in a running bond onto the base foundation 12 wherein the ICFs 13 define an interior wall space 18 that includes bracing ladders 23;
(3) disposing at spaced apart locations along the length 12L of base foundation 12 adjacent to the anchor dowel pairs 17 and spaced above the base foundation 12, a lower spar set 33a of multiple spar members that span the interior wall space 18 and penetrate the ICF panels 14 locating end sections of the spar members outside of the ICFs 13;
(4) injecting rigid polyurethane foam 53 in the interior wall space 18 and thereby surround the bracing ladders 23 and the portions of the spar sets 33 within the interior wall space 18;
(5) stacking onto the existing foam filled run of ICFs 13 additional runs of ICFs 13 each to a height of several panels 14;
(6) injecting rigid polyurethane foam 53 in the interior wall space 18 of each additional run of ICFs 13 before adding an additional run of ICFs 13;
(7) repeating steps (5 and 6) until one additional run of ICFs 13 would reach within several panel heights of the top 11b of wall 11;
(8) stacking a top run of ICFs onto the uppermost foam filled run of ICFs;
(9) disposing in the top run of ICFs in line with the lower spar sets 33a an upper spar set 33b that spans the interior wall space 18 and penetrates the ICFs 13 locating the end sections of the spars of the upper spar set 33 outside of ICFs 13;
(10) injecting rigid polyurethane foam 53 in the interior wall space 18 of the top run of ICFs 13;
(11) securing next to each anchor dowel 17 a connecting rod 22 that extends vertically to a height that disposes it adjacent an upper spar set 33b;
(12) securing to each connecting rod the end sections of the spars of a lower spar set 33a and an upper spar set 33b;
(13) securing wire fabric 57 exteriorly of surfaces 14b of the panels 14 of ICF 13; and
(14) applying a concrete membrane (typically pneumatically placed shotcrete or gunnite) to the exterior surfaces 14b of the ICF panels 14 to a thickness that encapsulates the anchor dowels 17, connecting rods 22 and end sections of spar sets 33.
Of course, various changes, modifications and alterations in the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. As such, it is intended that the present invention only be limited by the terms of the appended claims.
Claims
1. A high thermal resistant vertical wall supported on a base foundation having a length comprising:
- a plurality of ICFs on the base foundation each comprising generally parallel spaced apart panel members wherein each said panel member has an interior surface and an exterior surface with the space between the said interior surfaces defining an interior wall space;
- foam disposed in said interior wall space and
- a concrete membrane adjacent to said exterior surface of said panel members.
2. The high thermal resistant vertical wall of claim 1 further comprising:
- a plurality of bracing ladders supported at spaced apart locations on the base foundation within said interior wall space and surrounded by said foam.
3. The high thermal resistant vertical wall of claim 1 further comprising:
- a plurality of spar members spanning said interior wall space and having ends that are disposed outside of said interior wall space adjacent said exterior panel surfaces in a said concrete membrane and surrounded by said foam.
4. The high thermal resistant vertical wall of claim 2 further comprising:
- a plurality of spar members sets spanning said interior wall space and having ends that are disposed outside of said interior wall space adjacent said exterior panel surfaces in a said concrete membrane and surrounded by said foam wherein a spar member set comprises a plurality of spar members.
5. The high thermal resistant vertical wall of claim 3 wherein said spar members are made of fiberglass.
6. The high thermal resistant vertical wall of claim 1 wherein said foam is a rigid polyurethane closed cell foam.
7. The high thermal resistant vertical wall of claim 6 wherein said foam is high density.
8. The high thermal resistant vertical wall of claim 6 wherein said foam is low density.
9. The high thermal resistant vertical wall of claim 1 wherein said foam is formed by a combination of liquids that expand when exposed to the air.
10. The high thermal resistant vertical wall of claim 1 wherein said ICFs are stacked on the foundation in a running bond.
11. The high thermal resistant vertical wall of claim 4 further comprising vertical connecting rods disposed adjacent to the exterior surfaces of said panel members and affixed to said spar member ends and encapsulated in a said concrete membrane.
12. The high thermal resistant vertical wall of claim 4 wherein said spar member sets are disposed at spaced apart locations along the base foundation with only two spar sets at any given location where said spar member sets are in vertical alignment.
13. The high thermal resistant vertical wall of claim 4 wherein said spar member sets comprise two cross spar members each spanning said interior wall space at an angle to the vertical and each having end members generally that are vertical and parallel to said panel surfaces and disposed adjacent to a said exterior surface and two U-shaped spar members that span said interior wall space at generally right angles to said panel member surfaces and have end members that are generally horizontal and parallel to said panel exterior surfaces wherein said cross spar member end member lie between a said U-shaped spar member end members by which they are restrained.
14. A method of constructing a high thermal resistance wall having a top and a bottom onto a base foundation having a length comprising:
- (a) stacking a base run of ICFs onto the base foundation wherein said ICFs comprise spaced apart panel members having interior and exterior surfaces with said interior surfaces defining an interior wall space;
- (b) disposing a plurality of bracing ladders supported at spaced apart locations on the base foundation within said interior wall space extending to the top of the wall;
- (c) disposing in said base run of ICFs at spaced apart locations along the length of the base foundation a lower spar set comprising a plurality of spar members spanning said interior wall space and having spar ends that are disposed outside of said interior wall space adjacent said exterior panel surfaces; and
- (d) injecting close cell polyurethane foam forming liquids into said interior wall space in which said foam forming liquids expand to fill the space between said ICF panels and surround said bracing ladders and portions of said spar sets within said interior wall space with close cell polyurethane foam.
15. The method of claim 14 wherein said panels have a height and further comprising:
- (e) stacking onto the base run of ICFs an additional run of ICFs to a height of several said panels wherein said additional run ICFs comprise spaced apart panel members having interior and exterior surfaces with said interior surfaces defining an interior wall space and;
- (f) injecting close cell polyurethane foam forming liquids into said additional run interior wall space in which said foam forming liquids expand to fill the space between said additional run ICF panels and surround said bracing ladders with close cell polyurethane foam before stacking another additional run of said ICFs on to the previous said run of ICFs;
- (g) stacking onto the previous additional run of ICFs additional runs of ICFs each said additional run to a height of several said panels wherein said additional run ICFs comprise spaced apart panel members having interior and exterior surfaces with said interior surfaces defining an interior wall space and;
- (h) repeating steps (f) and (g) until an uppermost additional said run of ICFs reaches within several panel heights of the top of said wall.
16. The method of claim 15 further comprising:
- (i) stacking onto said uppermost said additional run of ICFs a top run of ICFs to a height of several said panels wherein said top run of ICFs comprise spaced apart panel members having interior and exterior surfaces with said interior surfaces defining an interior wall space;
- (j) disposing in said top run of ICFs at spaced apart locations along the length of the base foundation an upper spar set comprising spars having end sections wherein said spars span said interior wall space and penetrate through said top run ICF panels locating said spar end sections outside of said interior wall space and adjacent a said panel exterior surface;
- (k) injecting close cell polyurethane foam forming liquids into the interior wall space of said top run of ICFs in which said foam forming liquids expand to fill the space between said top run ICF panels and surrounds said upper spar sets and said bracing ladders with close cell polyurethane foam.
17. The method of claim 14 wherein the foundation includes embedded spaced apart anchor dowels at spaced apart locations along the foundation extending above the foundation to a height of several said ICF panels further comprising:
- (l) disposing adjacent each anchor dowel a connecting rod that extends vertically to a height that places it adjacent said spar ends of said upper spar set and adjacent said spar ends of said lower spar set;
- (m) securing said end sections of said spars of said lower spar set and said end sections of said spars of said upper spar set to a said connecting rod; and
- (n) applying a concrete membrane to said exterior surfaces of said ICF panels that comprise said base run, said additional runs and said top run to a thickness that encapsulates said anchor dowels, said connecting rods and said spar set end sections.
18. The method of claim 17 wherein said concrete membrane is applied under pressure.
Type: Application
Filed: Jul 2, 2012
Publication Date: Jan 2, 2014
Applicant: INTEGRATED STRUCTURES, INC. (Berkeley, CA)
Inventor: Roy Gary Black (Berkeley, CA)
Application Number: 13/540,007
International Classification: E04B 1/78 (20060101); E04C 2/20 (20060101);