Base & Cap FAQs

Base & Cap System™

Design & Selection – The key is follow Install Details.

  • The seal between the Cap and poly. panel doesn’t look weather tight. What do you recommend for roof with a shallow pitch? Properly installed, the Cap provides an excellent seal, even on a 1/12 (5%) pitch. Glass and acrylic are hard materials, requiring a gasket type seal on the glazing system cap. Polycarbonate is a resilient material. When the Cap is snugly installed, the pressure of the legs of the Cap causes the polycarb to give slightly, creating a watertight seal. One of the great advantages of polycarb is that gaskets are not required to achieve a watertight seal. Our Base and Cap has no gaskets and requires no silicone where the Cap meets the polycarb. The more parts of a glazing system, the more likelihood for leakage. Gaskets in glazing system caps will often shrink, creating a gap for water to enter. Also, because one sheet of polycarb runs from the ridge of a greenhouse to the overhanging eave, there are no horizontal joints, no impediments to water shedding off the glazing area, no water damming up and, consequently, leakage rarely occurs. The most often reported cause for leakage is loose Caps, (not tight enough when installed)
  • I do not see vent tape in your drawings? Vent tape is typically used in U-Profiles of plastic that, not only yellow, but also fit loosely. Without vent tape these plastic U-Profiles allow water, dust, pollen and bugs to enter. Our U-Profiles fit tight, vent tape not required. It is important to access our drawings and following these drawings carefully, should you choose to use our Install Systems. Using our components and misc. instructions from others will clearly lead to problems. No other company goes to the length we do to ensure a successful installation. Follow our guidelines to the letter and we ensure a quality installation. Plastic install components are junk. Aluminum will last, and you have a choice of colors.
  • Where do I use silicone? Each detail will indicate use of silicone, if required. The key is follow Install Details.
  • How do I determine quantity of silicone required? One tube of silicone will produce 25 linear feet of 1/4″ x 1/4″ silicone bead. We sell plastic compatible, 100% silicone.
  • My existing rafter framing is 4 ft. on-center, but the sheet is 4 ft. I would like to use your Base & Cap System. What do you suggest? You can cut the 8mm or 10mm double-wall sheet down to 47″. The sheet will fit and there will be sufficient sheet structure. If you need to use 16mm or 25mm Email with info on your project.
  • Where is Aluminum Tape used? Each detail will indicate use of tape, if required. The key is follow Install Details.
  • I am building a sunroom or greenhouse and would like polycarb and the Base & Cap System on the roof and glass on the vertical walls. We recommend filling wall openings with vinyl windows and patio doors. Windows may be custom sizes and door sizes are easy to work around. Fill in above gable end windows or doors with polycarb.
  • Please suggest touch up paint? For bronze we suggest Rust-Oleum, Bright Coat, Metallic Finish – Dark Bronze #7713.

Installation, See Base & Cap, The key is follow Install Details.

Polycarbonate Greenhouse and Sunroom Building Supplies