Patent Application
20100139186
Skylights can be applied to a roof deck using several installation methods. Certain skylights are supported on a curb which raises the skylight above the surface of the roof.
Foam insulated curbs have been utilized, such as those disclosed, for example, in Kiekhaefer U.S. Pat. No. 3,417,522; Jentoft et al. U.S. Pat. No. 4,073,097; and Moench et al. U.S. Pat. No. 4,233,493, as well as several others. Generally, these foam insulated curb structures are unitary structures formed in a mold. They may have limited structural integrity and, further, require a separate mold for each different size skylight. Further, since they are unitary in structure, they use a large amount of space during shipping and are difficult to transport and use at the construction site.
Other structures have been used to form curbing, such as simply dimensional lumber, such as 2×6's, and the like. These are difficult to assemble on site and, further, lend themselves to irregularities in size and variations in plumb. Further, the wood itself provides less than adequate thermal insulation, making the curb only minimally efficient portion of the skylight.
The present invention is premised on the realization that a skylight curb can be formed from structural insulated panels (SIP). More particularly, the structural insulated panels take the form of elongated plank components with an outer fastener engaging portion and an inner finish portion and an intermediate foam core. The edge structures of each of these planks are designed to provide for easy assembly. An edge of a first SIP plank includes a fastener-receiving insert at the end of the foam core, while the adjacent edge of a second SIP plank includes an elongated fastener-receiving portion, or wood portion, which overlaps the first SIP plank, allowing the two to be screwed together forming a precise 90° angle. Four SIP planks are fastened together to form a curb.
The formed rectangular curb structure can then be fastened to a roof substructure using L-brackets, or other similar brackets. A water tight seal between the curb and roof membrane is formed using flexible flashing. Finally, the skylight is simply placed on top of the curb structure laid on a bead of waterproofing sealant and fastened into place.
The objects and advantages of the present invention will be further appreciated in light of the following detailed descriptions and drawings in which:
As shown in
The curb 14 is formed from structural insulated panels or SIPs 20, 22, 24 and 26. The SIPs each include an outer portion or layer 28 which is designed to receive and hold a fastener, a central foam portion or layer 30 and an inner finished portion or layer 32. The length of the SIPs is determined by the size of the skylight while the height can be about 9 inches or more.
The outer portion 28 can be formed from any material that will receive and hold a fastener. Typically, it will be a wood based material such as plywood, particle board or OSB or metal. In particular, OSB having a thickness of from about ¼ inch to about ¾ inch can be used, and, in particular, OSB having a thickness of about ½ inch to 7/16 inch provides adequate structural integrity. To provide fire retardance a layer of dry wall (not shown) can cover the OSB.
The foam core is designed to provide insulation and is preferably a rigid foam such as polystyrene foam. It can have any thickness designed to achieve the requisite insulation. Insulation having a thickness of 1 to 5 inches can be used, with polystyrene insulation of 3 to 4 inches generally being considered as adequate, and, in particular, 3⅝ inch expanded polystyrene foam is suitable for use in the present invention.
The inner portion 32 provides a finished interior surface. It is not designed to be penetrated by any fastener and it is preferable to utilize a material that provides some structural strength to the SIP. In particular, a solid, non-foam plastic or polymeric material is suitable. In particular, melamine coated masonite material having a smooth innermost surface can be used in the present invention. Other materials which are suitable for interior portion 32 include, for example, wood having a finished surface, such as stained or painted wood, as well as other polymeric materials. Any material that does not require additional finishing facilitates installation and reduces expenses.
The SIP itself is formed by simply bonding the three layers together. This is generally done in a factory so that the SIP is structurally sound and dimensionally precise.
As shown, SIPs 20 and 22 are attached to SIPs 24 and 26 at corners 34. The end structures of the SIPs are designed to facilitate formation of these corners 34. SIPs 20 and 22 include an end portion 36 of the outer portion 28, which extends beyond the ends 38 and 40 of the foam and finished portion, respectively. Likewise, SIPs 24 and 26 include ends 42,46 which incorporate a wood insert 44 at the distal ends of the foam portion 30 wherein the wood insert is coextensive with the ends 48 and 50 of the fastener-receiving portion 28 and the inner finished portion 32.
The corners 34 are assembled by simply fixing an end portion 36 of SIP 20 or 22 adjacent an end 50 of SIP 26 and inserting screws 52 through the extended portion 36 into the wood insert 44. As the wood insert is tightly bound to the SIP, this holds the entire structure together forming a very precise 90° angle. The assembled curb 14, as shown in
Flashing 16 is then applied over the curb surface. The flashing can be either a continuous strip of flexible flashing, generally with a preapplied adhesive, or can be a preformed unitary structure configured to fit directly over the curb 14. The flashing 16 extends from the top surface 62 of curb 14 over the side 28 covering the L-brackets with a bottom edge 64 adhered to the membrane 56.
Preferably, the flashing is simply adhered to the curb and to the roofing structure with a preapplied adhesive. The skylight 18 is then applied to the upper edge 62 of the curb utilizing a urethane sealant 66. As shown, the skylight incorporates an integral condensate grill 68 around the inner peripheral edge of the curb adhered to the skylight with an adhesive bonding tape 70. The outer rim 72 of the skylight is then fastened to the side walls 28 of the curb, again with screws 74.
The skylight structure 10 of the present invention provides several advantages. The insulating factor of the SIP is extremely high due to the insulating foam core. The SIP also provides significant rigidity. Further, because the curb assembly can be brought to the roof in sections and assembled at the roof, construction costs are reduced. Due to the structure of the curb assembly, assembling the curb structure on the roof is relatively simple, requiring only tools that would be with the builder at the time. The screwed butt-joined panel edges are designed to provide precise 90° angles. Further, the maintenance free interior with the white melamine coated masonite curb liner 32 provides a finished inner surface that requires no additional trim.
The risk of cutting the membrane is reduced because no metal flashing is employed, yet the curb and skylight assembly are firmly fixed to the roof using simple L-brackets. Finally, the overall cost of production is significantly reduced. Because the SIPs can be formed without a separate mold, virtually any size skylight can be utilized simply by changing the length of the SIPs.
This has been a description of the present invention along with the preferred method of practicing the present invention wherein the invention itself should only be defined by the appended claims.
