Flashing is important both for appearance and weather tightness. Flashing should be of sheet aluminum. We have found the best results with pre-painted .040” or .032” stock. Note particularly the use of flashing detailed at a greenhouse eave situation such as that shown in Illustration 12. This blind flashing is especially important to provide a “fail-safe” in case of leakage at the eave. Do not penetrate the blind flashing at the rafter run locations. Apply sealant beneath the outside edge (next to the rafter runs) on each of the discontinuous perimeter sections at the bottom of the glazing, and also beneath the rafter extrusions (see Illustration 5, Sloped Glazing Layout, where it is indicated “Flash & Caulk Under Joints”). Sealant should also be applied beneath the bottom mitered corners. This will isolate the extrusion joints from any penetrations in the flashing and provide a small drain channel between the edge of the rafter runs and the ends of the bottom perimeter pieces and also a drain channel down the mitered corners. The flashing below these channels will allow any condensation that might form on the inside of the glazing or any external leakage to run down into the upper gutter and then run to the side and down the drainage channels, out the bottom of the installation and over the blind flashing without the seeping into the wood framing under the extrusions. If roofing is above a sloped SureSeal installation, be sure to extend the flashing far enough underneath the roofing so as to prevent water from backing up under the roofing. This is especially important in low slope applications. In area with exceptionally severe winter conditions you may want to use Thermal Break SuperSeal perimeters to reduce interior condensation on the inside edge of the SureSeal metal. The SureSeal intermediates do not require a thermal break divider as the gaskets provide separation of the inside and outside metal. You will find suggested flashing details throughout these Guidelines, but they don’t cover every possible application. Traditional roofing practices and common sense are your best guidelines in the design and installation of flashing. Side flashing should be provided that fits under the cap gasket and goes down along the side of the perimeter and along the wall or roof as shown in Illustrations 12. 13 or 15, Side Jamb.
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