•Ridge Flashing Installation: Flashing sections, as detailed below, are typically fabricated in 8 ft. sections. There are two way to proceed with the installation of flashing.

 

It is best to purchase this flashing from a sheet metal fabricator. Do a simple scale drawing that shows dimensions, angle, etc. At the edge of the flashing that covers the polycarbonate we suggest a 1/2" long bend (flange). Draw so that the leg(s) of the flashing are tilted down 5° from the actual pitch of your roof. This will create a small amount of pressure against the polycarbonate sheet, useful in achieving a watertight installation. Sheet metal should be a minimum of .019" aluminum or 30 gauge steel. Aluminum is easy to fasten through, easy to cut, but is a little flimsy and care is required in handling. Steel is more sturdy, harder to cut and requires pre drilling prior to fastening. Availability at your local sheet metal shop may be the limiting factor. Look in the Yellow Pages under Sheet Metal Work. Some shops, especially those that cater to glass installation contractors, will inventory bright glossy white and architectural medium bronze sheet metal in the thickness you will be looking for. These colors will be a close match to the Trim Components we offer.

 

1) The easiest method of installation is to set and screw down a section of flashing that covers the first sheet of polycarbonate (on freestanding greenhouses install sheets on both sides of the greenhouse). Set screws so flashing presses against polycarbonate, place a bead of sealant at this point { Lean-To Ridge & Freestanding Ridge } and stop there. Lay the next sheet of polycarbonate and fasten the Narrow Profile Cap so that it butts against the edge of the flashing that comes in contact with the polycarbonate. Now screw down the flashing and place a bead of sealant along the edge of flashing that comes in contact with the polycarbonate, and also where the Cap comes in contact with the flashing. Continue installing more polycarbonate and flashing. Overlap seams in flashing a minimum of 4". Do not cut to length as this will create a slight curl at cut & an uneven overlap. If the overlap ends up being 4 ft., so be it. This method provides a watertight installation, but care must be taken to lay a smooth bead of sealant on a cleaned surface.

 

2) A more difficult, but a cleaner looking and tighter installation involves installing the flashing after all sheets are set. See { Lean-To Ridge & Freestanding Ridge }. This involves acquiring access to the ridge with all polycarbonate in place. As mentioned in the Roof Access Notes above, this can be tricky and is best performed by individuals accustom to working on roofs or in situations where balance and care during installation procedures is second nature. If you are working on an attached greenhouse you may be able to gain access to this detail from the roof of the adjoining structure. When installing the flashing, first lay in place and mark where the flashing overlaps the Cap at sheet seams. Notch the flange at these locations to fit the Cap. When installed, the flashing will rest flat on the polycarbonate and the Cap. Failure to cut out for the Cap will result in a gap between the polycarbonate and the flashing, wavy looking flashing and a poor weather seal. Overlap seams a minimum of 4". Do not cut to length as this will create a slight curl at the cut and an uneven overlap. If the overlap ends up being 4 ft., ok. The only cutting required is an easy to cut, curved notch where the Narrow Profile Cap slides under the flashing. See drawing below.

 Sealant Selection & Application: Silicone is used below eave { Eave Detail }, along Lean-To Ridge & Freestanding Ridge flashing and at the interface between U-Profile and an Existing Wall. Use 100%, plastic compatible, silicone. A 1/4" bead is best. When spicing lengths of either Cap & Corner place a 1/4" bead of silicone at joint. Gently tool bead flat with saliva covered finger. Do not place same finger in mouth after tooling. The sealant is sticky and somewhat toxic. Joints at the interface of the Trim Components should be clean and securely fastened. Make sure U-Profile is butted tightly so that spiders do not get in and build a web. Clean all joints with isopropyl (rubbing) alcohol and let dry prior to applying the sealant. Allow sealant to dry for 24 hours before cleaning the polycarbonate and metal. Commercial Grade Dow 999-A Clear Silicone is available through Sundance Supply. Calculate running ft. of silicone required for your project. One tube will do 25 feet of a 1/4" bead.

 

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