While new construction projects are fewer and farther between these days, the tax credit for window and door replacements has kept our company plenty busy. A number of the houses we’ve worked on have been log homes, which are fairly common in our area, and we’ve developed some techniques that make these jobs go quickly. Since log homes typically have deep window jambs and custom trim that would be expensive to replace, our method focuses on preserving and reusing the finished woodwork.

The first step is ordering windows properly. It’s crucial to find a knowledgeable salesperson who understands how the windows will fit into the trim and can size the replacement units correctly. This typically eliminates the need for custom sizes. For the method shown here, the windows must have either folding or removable window flanges, so that spray foam insulation can be applied from the exterior.

Once the windows are delivered, we set up any necessary staging outside and prepare the interior by moving furniture and wall decorations out of the way and removing any blinds or draperies.

Keeping the site clean is probably the most important thing we can do to keep our clients happy, and it’s critical to getting referrals for new jobs. So we begin by covering the inside of the window with self-adhesive plastic film, the type usually used to protect floor coverings during construction. On the job shown here, the interior trim had a rough-sawn finish, so for good measure we added some masking tape around the edges. Next we carefully remove and label the exterior trim, so it can to be reinstalled after the new window is in place.

After removing the existing window, we compare its thickness with that of the new window and build a jig to mark the jamb for trimming. We use a small circular trim saw where it will fit and a Fein MultiMaster tool for the corners. Because these are critical finished cuts, we only use experienced carpenters for this task. Once the jambs are cut, we immediately clean up with the vacuum. The self-adhesive film really comes in handy here, because any airborne particles will stick to it. (With regular poly, the sawdust clings for a while due to static electricity, but it tends to fall off later when you remove the plastic.) After vacuuming, we pull down the film and fold it in on itself, trapping the sawdust and keeping the interior of the home clean.

We use precut shims of various thicknesses when installing the windows. Occasionally the existing trim is out of square, so we may have to remove the window and tweak the fit. Once the window looks good from both sides, we fasten the corners with screws, but only the bottom and top flanges at this point. Next we fold the side flanges out of the way and fill the gap between the window and the framing with spray foam. The side flanges are then folded back and fastened so that the bottom and top flanges can be unscrewed and folded out for foaming.

After taping the flanges, we reinstall the exterior trim — hopefully without having to remill it. From the inside, you’d never know the window wasn’t the original.

Chad Jenner owns and operates Jenner Construction in Ketchum, Idaho.