1. Field of the Invention
A roof mounting system and method for mounting an array of discrete modules to a roof.
2. Description of the Prior Art
Existing attachment systems for mounting solar and other equipment to the exteriors of building envelopes commonly follow one of two general approaches.
The first attachment system includes penetration of the envelope by mechanical attachment devices.
The second system consists of ballasting equipment in place by loads of magnitudes greater than the predicted wind uplift and overturning forces.
Each approach has significant drawbacks. For example, mechanical anchors compromise the integrity of the building envelope and increase the likelihood of leaks and magnify wind forces by concentrating them all at a limited number of attachment points.
On the other hand, ballasting can require loads greater than the building envelope or roof can support. Most commercial roofs are designed for a live load of 40 pounds per square foot, whereas wind uplift in Florida and other high wind areas can exceed 80 per square foot.
While some of the prior art may contain some similarities relating to the present invention, none of them teach, suggest or include all of the advantages and unique features of the invention disclosed hereafter.
The present invention overcomes these problems by keeping the wind as a distributed force over the entire footprint on the building envelope of the equipment being installed or a lesser attachment area as needed based upon site specific wind engineering.
The present invention relates to a roof mounting system and method for mounting an array of discrete modules to a roof.
The roof mounting system employs structural roofing insulation or water proofing adhesive such as spray polyurethane foam or other chemical agent to secure the roof mounting system in place. This transfers the load forces directly to large areas of the surface covering of the building envelope. Securing the roof mounting system in this manner does not alter the wind forces at a given location other than decoupling the internal portion (18%) of the total wind force from the external portion of the total wind force (82%). The building envelope resists internal pressure.
Furthermore, the roof mounting system resists the external wind force and transfers the force through the adhesion to the envelope of the building structural framing. The only change in forces experienced by the building framing is the relatively small additional gravity load of the roof mounting system adhered to the envelope.
The roof mounting system is particularly useful in securing a solar panel array to a roof by spray polyurethane foam that creates a minimal gravity load of about 6 pounds per square foot for typical installation well within the acceptable live load on any current code compliant building.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.
For a fuller understanding of the nature and object of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which: Similar reference characters refer to similar parts throughout the several views of the drawings.
As shown in
Specifically, a plurality of support rails each indicated as 1 is arranged on a roof 3 to cooperatively form a grid to support a plurality of discrete modules such as a photovoltaic panels 5.
The plurality of support rails 1 may be secured or adhered directly to the roof 3 by a spray polyurethane foam 2 upon the spray polyurethane 2 may be combined with or covered by a protective coating of elastomeric material.
Alternately, the support rails 1 may be mounted on a plurality of stanchions each generally indicated as 6. Each stanchion 6 comprises a base plate 7 coupled to an upright member 8 by a coupling element 9. Each stanchion 6 further includes a fastening member 10 including a centrally disposed aperture or hole 11 to receive a fastener 12 thereto to secure the rails 1 to a corresponding upright member 8 of the corresponding stanchion 6 by a corresponding rail clamp 13.
The base plate 7 of each stanchion 6 is embedded or adhered to the roof 3 by the spray polyurethane foam 2.
Spray polyurethane foam roofing systems exhibit excellent adhesion properties to a variety of substrates including metal, wood, concrete and built up roofing. However, the spray polyurethane foam must be protected by elastomeric coatings or other coverings to prevent UV-induced surface degradation.
Benefits of using spray polyurethane foam as an adhesive include; rigid, lightweight, flexible, wind resistant, effective in extreme weather and temperature conditions and high insulating values.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
Now that the invention has been described,
This application claims priority from pending provisional patent application Ser. No. 61/687,711 filed Apr. 30, 2012.