US20240301693A1

US20240301693A1 - Building party wall assembly

Info

Publication number: US20240301693A1
Application number: US18/118,426
Authority: US
Inventors: Chris Anderson; David Gauthier
Original assignee: Vantem Global Inc
Current assignee: Vantem Global Inc
Priority date: 2023-03-07
Filing date: 2023-03-07
Publication date: 2024-09-12

Abstract

The building party wall assembly comprises a first structural insulated panel and a second structural insulated panel separated by an air gap. The first structural insulated panel comprises a rigid foam insulation core, a first cementitious board disposed on one side of the core, and a second cementitious board disposed on the second side of the core. The second structural insulated panel comprises a rigid foam insulation core, a third double thick cementitious board disposed on one side of the core, and a third double thick cementitious board disposed on the other side of the core. Alternatively, the second structural insulated panel comprises two first cementitious boards stacked on top of each other disposed on one side of the core, and two second cementitious boards stacked on top of each other disposed on the other side of the core.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is in the field of walls for buildings with special measures for sound insulation and fire protection.

2. Description of the Related Art

In modular construction of multi-family buildings, it is required by the International Building Code (“IBC”) to have a minimum sound transmission class (“STC”) rating of at least 50 for sound attenuation, as well as a 1-hour fire rating, in all party walls. Sound control is important in lodging structures, multi-family apartments, condominium complexes, as well as senior living facilities or any building that includes dwelling units with shared walls.
Shared walls can mean unwanted noise from the unit next door and shared corridors can also mean less privacy. It is a challenge to get a stick-framed structure to meet both sound transmission and fire resistance ratings. For newer or remodeled multi-family housing units, building codes throughout the United States require a measure of sound privacy between dwelling units. The IBC specifies a minimum architectural design standard of privacy of 50 STC.
Commonly referred to as their acronym, SIPs, structural insulated panels are high performance building panels used in floors, walls, and roofs for residential and light commercial buildings. The panels are typically made by sandwiching a core of rigid foam insulation between two structural skins. These panels are fabricated in a factory and shipped to a construction site, where they can be assembled quickly to form a tight, efficient building envelope. Cementitious SIPs are one type of SIPs, using cement-fiber board as the structural facing material.
In SIP construction it is very difficult to achieve a STC 50 rating as well as a 1-hour fire rating without the addition of multiple layers of gypsum-based drywall and other materials. Typically, in SIP construction, sound transmission loss drops significantly in the 630 Hz range due to the configuration of the skins of the panels. “Sandwich panels” such as SIPs have a well-known problem when it comes to acoustical performance: because the various layers are adhered one to the other, at certain frequencies the composite panel enters into resonance, diminishing the acoustical damping at that frequency. This, in turn, affects that critical STC rating of the system, where code requires minimum performances for different applications. One of the critical applications is party walls between living units, where the STC rating is normally 50. This is difficult to achieve with any sandwich panel that is known in the prior art, regardless of the material composition. The way other SIP manufacturers achieve the 50 rating is by adding multiple layers of drywall/gypsum and rock wool to one side of the panel to add mass to increase the dampening effect. This is not easy to do and increases costs and installation time.
What is needed, therefore, is a building party wall assembly comprising SIPS that achieves an STC rating of at least 50, has a 1-hour fire rating, and that is faster and simpler to manufacture, and therefore more affordable than the prior art, and does not contain gypsum.

SUMMARY OF THE INVENTION

The present invention is a building party wall assembly that satisfies these needs. The building party wall assembly comprises a first SIP and a second SIP separated by an air gap. The first SIP comprises a first insulation core, a first cementitious board disposed on one side of the first core, and a second cementitious board disposed on the second side of the first core. The first and second cementitious boards have approximately the same thickness as each other. The second SIP comprises a second insulation core, a third cementitious board disposed on one side of the second core and a fourth cementitious board disposed on the other side of the second core. The third and fourth cementitious boards each have a thickness that is at least twice that of the first and second cementitious boards, or approximately twice the thickness of the first and second cementitious boards. Alternatively, two first cementitious boards are stacked on top of each other and disposed on one side of the second core, and two second cementitious boards stacked on top of each other disposed on the other side of the second core. It is important that the total thickness of the cementitious boards on the second SIP is at least twice that of the cementitious boards on the first SIP. These and other benefits, features, and advantages will be made clearer in the accompanying description, claims, and drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional front elevation of a building party wall assembly according to one embodiment of the present invention.

FIG. 2 is a cross sectional side elevation of the assembly of FIG. 1 .

FIG. 3 is a cross sectional bottom plan view of the assembly of FIG. 1 .

FIG. 4 is a cross sectional side elevation detail view of a representative cementitious board used in the assembly of FIG. 1 .

FIG. 5 is a cross sectional side elevation of a building party wall according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-3 show a building party wall assembly 100 of the present invention that achieves a minimum STC rating of 50 when tested under ASTM E90 and 1-hour fire rating under ASTM E119. The building party wall assembly comprises a first structural insulated panel (“SIP”) assembly 102 and a second SIP 103 separated by an air gap 110. The air gap 110 is preferably approximately 2.0 inches.
The first SIP 102 comprises a first rigid foam insulation core 105 having a first side and a second side, a first cementitious board 104 disposed on the first side of the first rigid foam insulation core 105, and a second cementitious board 104 disposed on the second side of the first rigid foam insulation core 105. Each cementitious board 104 is preferably approximately 0.5 inches thick. As assembled, the first SIP 102 is preferably approximately 4.5 inches thick.
The second SIP 103 comprises a second rigid foam insulating core 105 having a first side and a second side, two first cementitious boards 104 stacked on top of each other along their major surfaces disposed on the first side of the second rigid foam insulating core 105, and two second cementitious boards 104 stacked on top of each other along their major surfaces disposed on the second side of the second rigid foam insulating core 105 in the configuration shown in FIGS. 2 and 3 . As used herein, the term “major surface” means the large sides of a panel, board, core, or sheet as distinguished from the smaller edges of the panel, board, core, or sheet. As assembled, the second SIP 103 is preferably approximately 5⅝, i.e. 5.625, inches thick.
The rigid foam insulating cores 105 preferably comprise expanded polystyrene (“EPS”) foam. The cores 105 are also preferably approximately 3⅝, i.e. 3.625, inches thick.
The building party wall 100 also comprises a frame 106 comprising nominal 2×4 inch pieces of lumber disposed at the edges of each SIP 102 and/or 103. The SIPs can be joined edge to edge via the frames 106 as shown in FIGS. 1 and 3 to form larger building party walls 100. The term “nominal 2×4” refers to commercially available 2×4 inch pieces of lumber and it is known in the art that they measure less than 2 inches by 4 inches. The lumber is preferably No. 2 southern yellow pine lumber.
FIG. 4 is a cross sectional side elevation detail view of a representative cementitious board 104 that is used in the building wall assembly 100 of FIGS. 1-3 . The cementitious boards 104 comprise a Sorel cement board 108 reinforced with a fibrous layer 112 on the two major surfaces of the sheets. The fibrous layers 112 preferably comprise a fiberglass mesh.
The cementitious boards 104 may also comprise Vantem boards. VANTEM a trademark of Vantem Global Inc. Vantem boards are also described in US 2017/0101343 A1 by Zheng as a plate comprising a sizing agent and two fibrous layers disposed apart from each other. US 2017/0101343 A1 is hereby incorporated by reference as if it were fully rewritten herein.
FIG. 5 shows a second embodiment of a building party wall assembly 200 according to the present invention. The building party wall assembly 200 comprises a first SIP 102, a second SIP 202, and an air gap 110 separating the first and second SIPS. Like in the first embodiment, the first SIP 102 comprising a first rigid foam insulation core 105 having a first side and a second side, a first cementitious board 104 having a first thickness disposed on the first side of the first rigid foam insulation core, and a second cementitious board having approximately the same first thickness disposed on the second side of the first rigid foam insulation core.
The second SIP 202 of this embodiment differs from the second SIP 103 of the first embodiment. In FIG. 5 , the second SIP 202 comprises a second rigid foam insulation core 105 having a first side and a second side opposite the first side. A third cementitious board 204 having a second thickness comprising at least one major surface is disposed on the first side of the second rigid foam insulation core 105. A fourth cementitious board 204 having the second thickness comprising at least one major surface is disposed on the second side of the second rigid foam insulation core 105. The second thickness is at least twice the thickness of the first thickness. Alternatively, the second thickness can be approximately twice the thickness of the first thickness. In this regard, the second embodiment differs from the first embodiment only in that the cementitious boards 204 of the second SIP 202 are twice or more as thick but only one board is used per side. Therefore, the sound transmission reduction rating and fire resistance would be the same in the two embodiments.
The sound transmission reduction in both the first and second embodiments is due to the double thickness of the cementitious boards on the second SIP. The double thickness affects the resonance frequencies of the sound energy through the structures, thereby reducing sound transmission.
The configuration described above has been tested by an independent laboratories for sound transmission loss under ASTM E90 and for fire resistance performance under ASTM E119. In the tests, the assembly of the present invention achieved an STC rating of 53, which exceeds the required minimum 50, and a 1-hour fire rating. This achievement is made with only cementitious boards and rigid foam insulation cores of particular sizes and in a particular configuration. As such, the sizes and dimensions of the various materials are considered to be critical to its success.
The use of a building party wall assembly consisting essentially of only cementitious boards, insulation cores, and a frame in this novel configuration reduces the number of parts that are required to manufacture a building wall assembly. This helps to simplify the building process and reduce its cost. The assemblies are modular, so that assemblies can be factory-built to consistent quality standards. The result is that high-quality, affordable, and energy efficient apartment buildings and single family homes can be rapidly produced, and without the need for multiple layers of gypsum and additional materials to attain a similar sound rating or fire resistance result.
Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”. “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than % 1 of, within less than 0.1% of, and within less than 0.01% of the stated amount.
While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Claims

1. A building party wall assembly that reduces sound transmission and is fire resistant comprising:

a first structural insulated panel assembly;

a second structural insulated panel assembly; and

an air gap separating the first and second structural panel assemblies;

the first structural insulated panel assembly comprising:

a first insulation core having a first side and a second side;

a first cementitious board having a first thickness disposed on the first side of the first insulation core;

a second cementitious board having the first thickness disposed on the second side of the first insulation core;

the second structural insulated panel assembly comprising:

a second insulation core having a first side and a second side opposite the first side;

a third cementitious board having a second thickness comprising at least one major surface, the third cementitious board disposed on the first side of the second insulation core;

a fourth cementitious board comprising at least one major surface, the fourth cementitious board having the second thickness disposed on the second side of the second insulation core,

the second thickness being at least twice the thickness of the first thickness.

2. The building party wall assembly of claim 1, wherein the second thickness is approximately twice the thickness of the first thickness.

3. The building party wall assembly of claim 1, at least one of the cementitious boards comprising Sorel cement board.

4. The building party wall assembly of claim 1, wherein the first thickness is approximately one half inch.

5. The building party wall assembly of claim 1, each of the first and second insulation cores comprising rigid foam insulation.

6. The building party wall assembly of claim 5, each of the first and second rigid foam insulation cores comprising EPS foam.

7. The building party wall assembly of claim 1, wherein each of the first and second rigid foam insulation cores is approximately 3⅝ inches thick.

8. The building party wall assembly of claim 1, wherein the air gap is an approximately two-inch air gap.

9. The building party wall assembly of claim 1, further comprising a plurality of nominal 2×4 inch pieces of lumber disposed at the edges of each structural insulated panel assembly thereby forming a frame.

10. The building party wall assembly of claim 1, each cementitious board comprising a Sorel cement board reinforced with a fibrous layer on two major surfaces of the Sorel cement board.

11. The building party wall of claim 10, the fibrous layer comprising a fiberglass mesh.

12. The building party wall of claim 1, wherein none of the cementitious boards comprise gypsum.

13. A building party wall assembly that reduces sound transmission and is fire resistant comprising:

a first structural insulated panel assembly;

a second structural insulated panel assembly; and

an air gap separating the first and second structural panel assemblies;

the first structural insulated panel assembly comprising:

a first insulation core having a first side and a second side opposite the first side;

a first cementitious board disposed on the first side of the first insulation core;

a second cementitious board disposed on the second side of the first insulation core;

the second structural insulated panel assembly comprising:

a second insulation core having a first side and a second side;

two first cementitious boards each comprising at least one major surface, the two first cementitious boards stacked on top of each other along their at least one major surfaces and disposed on the first side of the second insulation core;

two second cementitious boards each comprising at least one major surface, the two second cementitious boards stacked on top of each other along their at least one major surfaces and disposed on the second side of the second insulation core,

wherein each cementitious board has a thickness that is approximately the same as each other.

14. The building party wall assembly of claim 13, at least one of the cementitious boards comprising Sorel cement board.

15. The building party wall assembly of claim 13, wherein each cementitious board is approximately one half inch thick.

16. The building party wall assembly of claim 13, each of the first and second insulation cores comprising rigid foam insulation.

17. The building party wall assembly of claim 16, each of the first and second rigid foam insulation cores comprising EPS foam.

18. The building party wall assembly of claim 13, wherein each of the first and second rigid foam insulation cores is approximately 3⅝ inches thick.

19. The building party wall assembly of claim 13, wherein the air gap is an approximately two-inch air gap.

20. The building party wall assembly of claim 13, further comprising a plurality of nominal 2×4 inch pieces of lumber disposed at the edges of each structural insulated panel assembly thereby forming a frame.

21. The building party wall assembly of claim 13, each cementitious board comprising a Sorel cement board reinforced with a fibrous layer on two major surfaces of the Sorel cement board.

22. The building party wall of claim 21, the fibrous layer comprising a fiberglass mesh.

23. The building party wall of claim 1, wherein none of the cementitious boards comprise gypsum.

24. A building party wall assembly that reduces sound transmission and is fire resistant consisting essentially of:

a first structural insulated panel assembly;

a second structural insulated panel assembly;

a plurality of pieces of lumber disposed at edges of each structural insulated panel assembly thereby forming a frame.

and

an air gap separating the first and second structural panel assemblies;

the first structural insulated panel assembly comprising:

a first insulation core having a first side and a second side;

the second structural insulated panel assembly comprising:

the second thickness being at least twice the thickness of the first thickness.