Ridge Flashing Purchase & Install Introduction -------- - - Back to Install Details
 Suggestions for purchasing ridge flashing. Use Freestanding Ridge or Lean-To-Ridge details as a guideline. Print the page if the detail is appropriate for your application. Do a scale drawing of the flashing needed for your ridge. 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 medium architectural bronze in the thickness you will be looking for. In high wind areas use Big Stretch, not silicone, to bond tip of Ridge Flashing to poly.
Lumber Yards often stock freestanding flashing sections, in white, for steep pitch roofs. Bend as required for your roof.
Flashing Installation: Flashing sections, as detailed below, are typically fabricated in 8 ft. sections. There are two ways to proceed with the installation of flashing.
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.