STRUCTURAL INSULATED PANEL FOR BUILDING CONSTRUCTION
A structural insulated panel (SIP), such as 8 foot×24 foot, is made with a foam plastic core, oriented strand board on each face, and structural paper on either side of that, all bonded together. The oriented strand board capped with structural paper provides a particularly strong wall structure. Also, the structural paper provides a finished surface as manufactured. SIP-to-SIP joints are created using an insert sandwiched between end portions of in-line-joined SIP panels.
This application claims benefit under 35 U.S.C. §119(e) of provisional application Ser. No. 61/056,217, filed May 27, 2008, entitled STRUCTURAL INSULATED PANEL FOR BUILDING CONSTRUCTION, the entire contents of which are incorporated herein in its entirety.
BACKGROUNDThe present invention relates to structural insulated panels such as for building exterior walls, and building structures using same.
Structural insulated panels (SIPS) have been around for a number of years. In the 1950's until about 1980, panels were made 4 feet wide and up to 12 feet long with commodity plywood and other materials. Some of these panels have finishes that were acceptable as exterior wall surfaces. The most common was a plywood pattern called reverse board and batten or sometimes T 1-11 ply. The inside of that was a material such as drywall or plywood. The center of these panels was plastic foam to complete a SIP panel.
The SIP panels discussed above were largely superseded when oriented strand board (OSB) became available in 8 foot by 24 foot sheets. The 4 foot wide panels were too costly and inefficient to install when one big panel could replace six small 4-foot-wide panels. However, a problem with this big 8 foot by 24 foot panel was that it did not have a finished surface on the inside nor outside, since OSB does not provide it. Thus, the big panels were usually covered with drywall on the inside and covered with exterior siding on the outside. Unfortunately, this process of covering inside and outside surfaces after building/wall construction is very expensive and made construction with SIPs more expensive than conventional “stick” construction. Even though SIP construction could save 30% to 50% of the heat loss, there has been continued resistance to use the SIP systems because of costs of material versus “stick” construction.
SUMMARY OF THE PRESENT INVENTIONOne aspect of the present invention is a structural insulated panel made with a foam plastic core and oriented strand board attached on either side to form board faces. The oriented strand board faces are capped with a structural paper that provides a finished surface. The core, OSB and structural paper are all securely bonded together.
Another aspect of the present invention is a “frameless” building where exterior walls are constructed primarily using structural insulated panels.
In another aspect of the present invention, a building wall includes two structural insulated panels positioned in-plane and with end edges adjacent. Each panel includes a foam core, an OSB facer on each side, and structural paper on each side. Each panel also includes an end portion with OSB facer extending beyond an outer surface of the foam core to define a cavity and an insert positioned between the end portions and extending into the cavity. The insert includes a foam core and OSB facer on each side, the OSB facer on the insert fitting inside the OSB facer on the panels; and fasteners fastening each panel to the insert.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.
The illustrated structural insulated panel (SIP panel) is large in size, such as 8 foot by 24 foot, and further incorporates outer layers forming high grade exterior and interior finishes as manufactured. The large size reduces on-site construction costs, and the exterior and interior finishes reduce on-site finishing costs. As a result, the present SIP panels reduce the overall cost of total building construction, so that the completed cost is less expensive than “stick” construction (e.g., wood stud framing for “framed” buildings having an on-site added outside such as vinyl siding and an on-site added inside such as drywall). The present SIP panels also save up to 50% of the heating and cooling costs, as well as meet fire code regulations.
This invention applies a finish in the factory to these large SIP panels. A combination of changed factors and upgrades of materials with the oriented strand board (OSB) and structural insulated paper makes for a panel finished inside and out.
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- 1. The OSB supplied is a higher grade that has minimum edge swell so that it is more suitable for exteriors, and its thickness is selected for functional requirements of the application of use. For example, the OSB thickness can be ¼″ to ¾″, or more typically about ⅜″ to ½″.
- 2. The OSB is treated and has a high degree of fire resistance for the inside to help meet building fire codes.
- 3. A structural paper (Kraft) with a polyurethane impregnation is used to face the OSB. Urethane impregnation of the Kraft paper is usually from 20% to 35%.
- 4. A waterproof adhesive is used to apply the structural paper to the OSB. The adhesive is of a fire-resistant type to help meet building codes. The adhesive penetrates well into the OSB to prevent delaminations.
- 5. A prime coat of white paint is applied to the structural paper to make panel more weather-resistant on the outside and ready for a finish coat on the inside by the owner in the field.
- 6. The outer and inner faces of prime paint, structural paper and OSB are laminated to both sides of the plastic foam. (Alternatively, one or both of the prime paint and the structural paper can be left off one side.)
- 7. The foam is usually an Expanded Polystyrene, Extruded Polystyrene or Urethane foam plastic. The foam acts as an insulator and as part of the structure. It can have whatever foam weight and additives that are appropriate for a particular application. It is contemplated that expanded foam having a weight of about 0.8 to 2 pounds per cubic foot, or more preferably about 1 pound per cubic foot will work well in many applications.
- 8. The application of the paper to the OSB must be done with heat and pressure for good bonding. The system can be either accomplished with a flat bed press or a roller press where the heat is transferred through the paper very rapidly since it is very thin. Thickness of the paper is typically 0.011 inches to 0.022 inches.
- 9. The SIP panels can be cut on-site or pre-cut at the factory.
By way of example, structural paper is commercially available and can be used in the present SIP. Some grades of structural paper have a tensile strength in a machine direction (parallel a longitudinal plane of the paper) of over 15,000 psi, which is up to about half a tensile strength of mild steel. When adhered to outside and inside surfaces of an SIP arrangement, a strength of the structural paper adds significant beam strength to the SIP.
The illustrated SIP panel (
The building (
It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.
Claims
1. A structural insulated panel comprising:
- a foam plastic core and oriented strand board (OSB) attached on either side of the core to form board faces, the board faces being capped with a structural paper that provides a finished surface; the core, OSB and structural paper all being securely bonded together.
2. The structural insulated panel defined in claim 1, wherein a prime paint is applied to the outer face of the structural paper.
3. The structural insulated panel defined in claim 1, wherein the adhesive used to bond the paper to the OSB is waterproof and adds to the fire resistance.
4. The structural insulated panel defined in claim 1, wherein the plastic foam core is one of Expanded Polystyrene, Extruded Polystyrene, or Urethane.
5. The structural insulated panel defined in claim 1, wherein the OSB has added chemicals to reduce the edge swell and increase the fire resistance.
6. The structural insulated panel defined in claim 5, wherein the OSB is at least about 2½ inch thick to provide good fire resistance.
7. The structural insulated panel defined in claim 1, where the panel size is very large, such as 8 foot by 24 foot, to eliminate the need for many small panels with numerous junctures.
8. A building comprising a plurality of the structural insulated panels defined in claim 7, the plurality of panels being attached together to form walls without wood framing, whereby the interconnected arrangement of large panels speeds erection of the building, improves building structure, and reduces energy loss through the building walls once constructed.
9. The structural insulated panel defined in claim 1, where a panel substantially forms a structural wall or roof of a building.
10. A building wall comprising:
- two structural insulated panels positioned in-plane and end edges adjacent; each panel including a foam core, an OSB facer on each side, and structural paper on each side; each panel including an end portion with the OSB facer extending beyond an outer surface of the foam core to define a cavity; and
- an insert positioned between the end portions and extending into the cavity; the insert including a foam core and OSB facer on each side, the OSB facer on the insert fitting inside the OSB facer on the panels; and
- fasteners fastening each panel to the insert.
11. The building wall defined in claim 10, wherein the fasteners include shafts that extend through at least one of the OSB facers on the insert and through an adjacent one of the OSB facers on the panels.
Type: Application
Filed: May 22, 2009
Publication Date: Dec 3, 2009
Inventor: William H. Porter (Saugatuck, MI)
Application Number: 12/470,573
International Classification: E04C 2/20 (20060101); E04C 2/34 (20060101); E04B 1/62 (20060101);