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About This Project
Replacing an aging picture window with a new bow window produces lots of benefits. It provides better ventilation, better views and better comfort. It updates the look of your house, both inside and out. And it provides a great place for your cat and plants to sunbathe. But what I like most is the way a bow window makes a room look and feel larger—even though the “bulge” adds just a few square feet. They’re a great addition to a living room, dining room or family room, and have a particular knack for making a cramped eating nook feel roomier.
The steps for installing a bay window—one that juts out farther, usually at a 30- or 45-degree angle—are nearly identical to those for a bow window. In fact, the first part of this article provides the basic steps for installing any window. Here’s how.
A Project That’s as Easy or Difficult as You Want It to Be
How tough is this project? Well, to some extent, you get to choose. If the thought of bracing up and tearing into your house to install a new header is daunting, buy a window that’s the same size as or slightly smaller than the existing one. You won’t need to tackle the major structural work, making this a project a confident beginner can do. Creating a new opening for a taller window isn’t that much more difficult; you simply lower the sill by shortening the cripples.
But if you widen the opening (and add cabinets and a window seat as we did), the project becomes more challenging. You’ll be tackling both brawny rough carpentry work and detailed finishing work, perhaps even rerouting heat ducts and electrical wiring. You’ll need to be comfortable handling power tools and allot plenty of time to finish the project. Our bow window was 6 in. wider and 4 in. shorter than the picture window it replaced, so we took the hard route.
Either way, formulate a game plan so you can pull out your old window and get the new window installed in the opening in a single day. This means having the room cleared out, temporary support wall (if necessary) in place, tools and materials at the ready, new window on site and helpers lined up ahead of time. You don’t want to lie awake in bed at night wondering if hail, bats or the boogeyman will be crashing through flimsy plastic stapled across an unfinished opening.
Remove the Old Window
You’re going to make a dusty mess, so move the furniture out, seal up the ducts, lay down a dropcloth and cover the doorways with plastic.
If you’re installing a larger header for a wider opening, you’ll need a building permit. Some inspectors will help you determine the correct header size; others will require calculations from a structural engineer—especially for openings exceeding 8 ft.
If you’re installing a larger header, build a temporary support wall 2 ft. back from the existing wall.
Carefully pry the interior molding from around the window with a flat bar, then set it aside. You may need to reuse it, since some older moldings are difficult to match. Use a reciprocating saw to cut through any finish nails that secure the window jamb to the window opening.
Use a pry bar to remove the trim or brick mold that surrounds the window outside and helps hold it in place. Be careful; sometimes your window will come out along with it. If your window is metal or vinyl clad, built-in nailing flanges may be securing it to the exterior sheathing and framing. If removing the exterior trim doesn’t give you access to these nails, use a circular saw to cut back the siding 2 in., then remove the nails with a flat bar. With the help of your spouse, neighbors and kids, remove the window.
Note: Brick, stucco and other types of siding present their own unique challenges. Cut back or remove only as much of these materials as necessary to get the old window out and the new window in. You can try to patch gaps between the edges of the window and the remaining siding, brick and stucco with like materials, but getting an exact match can be difficult. Filling gaps with wide trim boards is often lots easier.
If you’re installing a larger header, shut off power to all electrical outlets and switches in the wall, then remove the drywall or plaster. We removed everything “down to the studs” along the entire wall; it’s easier to fit and tape all new drywall or plaster, corner to corner, than to match the thickness and textures of the old and the new. It also allowed us to upgrade the insulation and install cable and a new telephone line.
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