Skylights placed on sloped roofs have a tendency to be leak-prone. Further, the costs are high when it becomes necessary to alter the roof sheets to accommodate the skylights, and there is an ongoing need to address loads imposed by heavy snow loads or personnel. These problems are exacerbated as the skylights increase in size and comprise a large portion of the roof.
Skylights are composed typically of four metal curbs around its perimeter. The curbs are typically made of sheet steel in the range of 14 gage thickness or aluminum in the range of 0.125″ thickness and are insulated by fiberglass batts or isocyanurate blocks. The longitudinal skylight curbs are made in sections which are screwed or bolted together so as to make long vertical curbs. The width-wise distance between curbs is specifically set so that metal roof panels which comprise the main roof will allow the skylight curbs to occupy the area which would have been occupied by one or two or three metal roof sheets. By making these curbs to a specified width, the roof sheets immediately below the skylight can be assembled in the normal fashion and will join each other in their normal seaming method. Typically, the skylights are placed with one end at the ridge of the building, thereby eliminating the need for crickets or saddles. Backseams formed by crickets or saddles have been one source of leakage in many skylights in the past.
Seams and the resulting leakage have been a source of problems for skylight systems. As the size of the skylight increases so too must the framing and thus the number of joints and scams, especially within standing seam roofs which comprise upright legs and thus form even more seams at the skylight framing. The rooting industry seldom uses skylights within standing seam roofs, mainly because the standing scams direct water flow downward resulting in water being directed into the frame. Because of this, skylights in the past have typically been installed as a large number of small units. However, it is difficult to put “crickets” in a standing seam roof because you are required to navigate around the standing scams. If the standing seams are cut in the process it may weaken the structural strength of the panel.
There is a need then for a skylight system which maintains the aesthetics of being wide and narrow so as to occupy a large-area as a single panel but which eliminates the potential for leakage, especially within sloped, standing seam roots.
The present invention comprehends a large-area skylight system which includes a very long skylight which, due to its length, delivers natural lighting from the center of a building to the eaves. To accommodate such a skylight, a framing system is provided which eliminates horizontal joints, cases installation, eliminates leakage water, can handle a load, and which can seat panels of varying thickness.
Accordingly, provided is a large-area skylight system comprising a curb forming a perimeter of a skylight adapted to be located within a field of roofing sheets. A cross member has an upper flange and a lower extremity, the cross member coped so as to allow the flange to rest on and be secured to the curb perpendicularly across the curb using a fastener, the lower extremity abutting a side of the curb and having defined therein a screw boss for accepting a screw, wherein the cross member is stiffened at the curb such that the skylight can handle a load. A base frame has an inside edge and an outside edge, the base frame configured to rest on the flange over the curb. Next, a cap frame having an interior side and exterior side is disposed over the base frame. A glazing material is then adapted to be secured between the base frame and the cap frame over the cross member along an entire length of the base frame and the cap frame to form an entire length and width of the skylight as a single panel.
To ease installation, the base frame has a side-defined channel cavity, and the cap frame has a downward leg formed integrally along its exterior side and angled therefrom for removable placement within the channel cavity, wherein the leg forms a fulcrum at a contact point between the base frame and the cap frame.
To accommodate a panel of variable thickness, the base frame has a lower channel cavity defined below the upper channel cavity to accommodate the downward leg when the glazing material is of lesser thickness.
Finally, to help exhaust water from the system, because a joint is formed when at least two base frames are joined, a dam is disposed within the base frame uphill from each joint, and a weep hole is defined within the base frame uphill of the dam, wherein water flowing into the base frame is stopped by the dam and exhausted through the weep hole prior to the water reaching the joint. These and other critical features are real zed by the instant invention as follows.
The invention will now be described in detail in relation to a preferred embodiment and implementation thereof which is exemplary in nature and descriptively specific as disclosed. As is customary, it will be understood that no limitation of the scope of the invention is thereby intended. The invention encompasses such alterations and further modifications of the principles of the invention illustrated herein, as would normally occur to persons skilled in the art to which the invention relates. This detailed description of this invention is not meant to limit the invention, but is meant to provide a detailed disclosure of the best mode of practicing the invention.
With reference then to
Preferred glazing material 10 comprising the skylight panel itself is a plastic translucent or transparent panel such as polycarbonate which combines strength with aesthetically-pleasing qualities. Structural steel or aluminum cross members 8 are located underneath the glazing material 10 on as to provide reinforcement against deflection which would result from positive loading, including loads imposed by snow or personnel. Each cross member 8 has an upper flange 8a and a lower extremity 8b and is coped to allow the upper flange 8a to rest on and be secured to the curb 2 perpendicularly across the curb 2 using a fastener 13, such as a screw, rivet, bolt or the like. Preferably upper flange 8a travels the entire width of curb 2 to rest “entirely” on the curb 2. The lower extremity 8b therefore abuts a side of the curb 8, and because the lower extremity 8b has a screw boss 8c defined therein for accepting a screw 27 (screw, rivet, bolt or the like), the cross member 8 is stiffened at the curb 2 such that the skylight 1 can handle the load. The cross members 8 also rigidize the metal curbs 2 and thus the entire system. For instance, the screw 27 passes through curb 2 and into the screw boss 8c of extruded aluminum cross member 8. Further, because cross member 8 is coped so as to allow its upper flange 8a to lie on top of curb 2, fastener 13 is able to pass through the upper flange 8a and thus further secure cross member 8 to the curb 2. This method of fastening at the upper extremity or upper flange 8a and lower extremities 8b in part creates stiffening to the curbs 2 and creates the ability for cross member 8 to be structurally capable of handling loads which may result from the deflection of the glazing material 10 due to snow loading or to traffic by personnel. In this way, a critical safety factor is achieved.
Resting over of the curb 2 is a base frame 3, typically an aluminum extrusion. “Over” as used in relation to the curb 2 means the base frame 3 is never in contact with the curb 2, only slightly above the curb 2 held off entirely by a combination of spacers 12 and upper flanges 8a of cross members 8, as below. Specifically, the base frame 3 has an inside edge 3a and an outside edge 3b (relative to position of glazing material 10). Defined at said outside edge 3b (exterior to the base frame 3) is an upper channel 15 and a lower channel 15a, each of which aid in installation depending on the size of the glazing material 10 as will be further described. Base frame 3 is configured to rest on the upper flange 8a of the cross member 8 over the curb 2. Fastener 13 is adapted to secure the base frame 3 to the upper flange 8a of the cross member 8 while simultaneously securing the upper flange 8a to the curb 2. Base frame 3 is also held slightly off curb 2 by a spacer 12 (preferably elastomeric). This spacer 12 allows structural cross member 8 to be coped and have its upper flange 8a also rest under base frame 3. Near thermal break 28, a lower gasket 17a is situated along the inside edge 3a for disposition against the glazing material 10 such that this integral, lower gasket 17a supports the glazing material 10 on one side, i.e. its underside.
Base frame 3 is typically installed in pieces from 5 ft. to 12 ft. in length. As a result, joints 5 may form when at least two base frames 3 are joined. The joints 5 between said base frames 3 are vulnerable to leakage if water should run down inside base frame 3 in the area adjacent to the head of fastener 13. This problem is solved by installing a dam 11, typically composed of sealant or an elastomeric foam, the dam being located just uphill of each joint 5 in base frame 3, “uphill” used in relation to sloping roof. Further, a weep hole 6 is defined just uphill of said dam 11. Therefore, if water flows into and along the inside of base frame 3, it will be stopped by dam 11 and exhausted out through weep hole 6. In this way, the joints 5 between framing members 3 are protected.
Next, a cap frame 4 has an interior side 4a and an exterior side 4b and is disposed over the base frame 3. The cap frame 4, typically an aluminum extrusion, contains the integral, upper gasket 17 which makes contact with the upper surface of the glazing material 10 and secures it against upward loads, as the cap frame 4 is mated to base frame 3. Cap frame 4 has a downward leg 14 which rests within the upper channel 15 of the base frame 3. This contact point becomes a fulcrum whenever cap screw 16 is tightened such that elastomeric gasket 17 located at one end of cap frame 4 is driven downward to contact and hold the glazing material 10. Cap frame 4 also includes an integral, opposing leg 14a formed to its exterior side 4b and also integral with the downward leg 14, but opposing leg 14a angles away from the downward leg 14 so as to shield the upper channel cavity 15.
Glazing material 10 is a plastic translucent or transparent panel such as polycarbonate and which can be installed in one piece traveling the entire length of the skylight 1. Shown in this embodiment, for example only, is glazing material 10 having a thickness of 32 mm. Glazing material 10 is adapted to be secured between the base frame 3 and the cap frame 4 along the entire length of the base frame 3 and cap frame 4 to therefore form an entire length and width of the skylight as a single, large-area panel.
Additionally, and as it relates to installation, the instant large-area skylight system includes flashing 20, which is preferably metal. The flashing 20 has an upper leg 21 and an angular lower leg 21a with the upper leg lapping under the base frame 3 and secured to the curb 2 using a flashing screw 22. At the outside of curb 2, the metal flashing 20 is installed to direct water over portions of the roofing materials below. As above, the upper leg 21 may be installed prior to the installation of base framing member 3, thus allowing leg 21 to lap under base frame 3. An alternative configuration will be shown in
Base frame 3 further comprises an internal screw track 18 defined proximate to the outside edge 4b to accommodate a cap screw 16 (screw, rivet, bolt, fastening means). When cap screw 16 is driven home, its length is such that its point 26 is driven into the bottom of screw track 18. This “bottoming out” of cap screw 16 prevents the screw from being overdriven and thus bending cap frame 4 or, alternatively, causing upper gasket 17 to bear against glazing material 10 with undue compression force, i.e. excessive pressure which could cause breakage or damage. For cosmetic purposes an aluminum cover 19 may be snapped onto cap frame 4 for purposes of hiding the exposed heads of cap screws 16.
With reference to
An alternate method for installing flashing 20 is also shown in
The instant application claims benefit of provisional application Ser. No. 61/467,536 filed Mar. 25, 2011, the disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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61467536 | Mar 2011 | US |