On this video, we explain to Dennis, a prospect client, how new impact windows can be installed at his existing kitchen pass-through opening. To illustrate the explanation, we drew in 3D the existing opening and the new impact-resistant window frames. Also, we drew the wood bucks needed to complete the installation. This is an idea. For the wood bucks, a professional engineer needs to provide signed and sealed calculations to be incorporated into the permit package submission. For your information, most product approvals allow for 1X wood bucks in their certifications. In a wood buck section larger than that, it must be calculated by an engineer and must be site specific.
Installing new impact-resistant windows at kitchen pass-through openings is a very common request in South Florida. In Miami, this is a very typical condition.
As always, this is just a practical solution that we have used in the past, and it has been approved. You must run it by a professional engineer to confirm.
Brief Explanation about Use of Wood Bucks or Buckstrips
Most Miami-Dade County and Florida product approvals for windows and doors contemplate the use of wood bucks as part of the installation condition. However, they are approved if they are less than 1-1/2" thick. As per PGT Industries' Horizontal Roller's NOA#20-0406.04 (taken as an illustrative example), "all wood bucks less than 1-1/2" thick are to be considered 1X installations. 1X wood bucks are optional if unit is installed directly to substrate." On the other hand, if you need to use bigger wood bucks, this referenced NOA states that "2X bucks (when used) shall be designed to properly transfer loads to the structure."
Use of Professional Engineer for Site-Specific Condition
When installing the windows shown on this video, and you need to fill a 1-1/2" gap or greater, then 2X bucks shall be designed by the engineer or the architect of record. When you apply for the permit, you can provide the proper product approvals, together with the signed and sealed designed (and calculations) by a professional engineer or architect.
Edge Distance and Anchor Embedment Considerations
It is also important to consider two important attachment factors, such as the edge distance and the anchor embedment. The edge distance has to do with the minimum distance from the edge of the substrate (column, beam, structural wall, etc.) to the location of the screw. The minimum edge distance varies from product to product. To find out the required value, you also reference the product approval. The value will depend on the screw (or anchor) used and the substrate to where you will attach the product. On this particular example, if we use the PGT horizontal roller attached to concrete by using a 1/4" steel Ultracon, then the minimum edge distance is 2-1/2". The minimum embedment distance, on the other hand, is the minimum dimension in which the anchor must penetrate the substrate.