Until very recently, the plywood clips used to install plywood covers on windows were not permitted for use by TDI. TDI has recently updated their listings for permitted shutters and the plywood clips are now permitted with some restrictions. The installation guide SHU-122 can be downloaded from the TDI website and should be followed closely to maintain the effectiveness of the clips and to not affect your windstorm insurance coverage.
Illustration 1) The clip must have the PLYLOX logo engraved on it to be permissible for use.
There are two assemblies permitted, one for brick veneer and one for wood siding and trim. The pressure ratings for the panels are +- 40 psf (pounds per square foot) which makes them permissible in most city locations. Those pressures might be exceeded on the island or out in the country where there is little additional protection from the wind, so it is recommended you check the pressures anticipated in your location before using the clips. The installation guide specifies the use of the PLYLOX brand stainless-steel since they were the only ones tested (see illustration 1). The clips must be used with the proper thickness plywood sheets and cannot be used with OSB or other structural wood panels. The installation also specifies the use of 2 x 4 stiffeners on the plywood panels (see illustrations) to meet TDI requirements. If any information in this blog conflicts with TDI SHU-122 the TDI document should be the controlling document.
Installation 1
For wood frame openings. Maximum size is 60 inches wide. Clips go on either side 3 inches from the top and bottom and every 6 inches between.
Installation 2
Brick framed opening. Maximum size is 36 inches wide. Clips go on either side 3 inches from top and every 6 inches between.