Last winter while at a job site, a client had inquired whether there was a cost-effective remedy to minimize or possibly eliminate a draft that occurs in the area close to a bay window, rendering the space virtually unusable on the coldest of days. A simple, half-day project rectified the issue, and the process was subsequently featured in a Reno Boss column. Having experienced a similar plight, one of my readers reached out to further inquire.
The issue regarding the draftiness at a bay window build-out is fairly easy to understand; due to the lack of cohesive insulation at floor level where the area cantilevers past the footing, and because the air is free to move below the cantilever, the interior space adjacent a bay window can experience a noticeable deviation from optimal room temperature during the winter months. As such, a simple yet effective DIY solution can be implemented quite easily, usually in less than four hours. And the best part is, there is no need to modify any existing exterior surface to accomplish the project successfully.
Using treated two-by-four lumber, a frame is constructed below the bay window along the footing. Prior to positioning any of the boards, the entire area is first lined with a thick poly. The back frame is then set into place, at just slightly below ground-level terminating one-and-a-half inches before the underside edges of the bay window build-out, at each end. The front side of the frame is also inset one-and-a-half inches from the front of the bay window, keeping the poly on the outside of the entire framework. The front and back frames are then secured to the underside of the bay window. Framing for the angled sides is then established by affixing boards to the top and bottom of the front and back frames, ensuring that the front face remains level.
With the framing intact, the entire poly-lined cavity is filled with fibreglass insulation. Once every little crevasse is packed, the poly is then pulled tight and stapled along the front areas of the framing. To seal the cavity, blue Tuck Tape is used at every seam. The edges along the footing are then caulked to seal the poly against the house and where the framing meets the underside of the bay window build-out. With these initial preparatory steps in place, it’s time to implement the esthetics.
Prior to the build date, a sample of the concrete footing was used to colour-match a gallon of high-grade exterior paint. Panels are cut from half-inch treated plywood for the front face, and both angled side faces of the newly introduced framework. The panels are first primed, before being affixed to the frame using two-inch ceramic screws. A grey caulk is then applied along every seam of the panels, along the footing and below the bay build-out. Caulk was also used to fill every screw hole, smoothed out for total concealment. After the caulk is allowed to set, the panels are given two coats of the colour-matched exterior paint. To ensure the best potential for blend, the concrete footing adjacent the side panels of the newly introduced below bay window frame is also given a quick pass with the roller, to ease any colour discrepancies. At a glance, it appears as though the existing footing now follows the contour of the bay window, which is the sought-after look.
By removing the air movement below the bay build-out, and insulating the cavity from ground-level to the underside of the build-out, the interior space at the bay window will better retain heat and, most importantly, allow temperature consistency within the space rendering it useable. This is a cost-effective and easy-to-implement project that provides both functionality and the desired esthetics.
My reader mentioned he had searched for a fix for years, and my column offered him the solution. That warms my heart, because I’m certain this fix will warm his interior.