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What You Need to Know When Replacing a Window in an Existing Wall


on May 28, 2020


When it comes to home repair jobs, few choices can produce a more dramatic impression than replacing your home windows. But while many other improvements can be completed with a little work and a good blueprint, replacing a home window demands substantial work and a good deal of technical knowledge.

As a result, replacing your windows is no easy job. You’ll want to understand what type of window is necessary, the specific plans required for replacing the window based on the size of the opening, and what materials it will take to make the proper fit for your replacement window.

Here are a few thoughts you may need to consider:

What is Your Frame’s Condition?

The condition of the window frame is the first prominent factor in matching the correct type of window to your replacement project. There are two types of window installation: full-frame and pocket. If you are constructing a new window frame, taking out a damaged frame or otherwise pulling the wall down to the studs, look for new construction windows, also called full-frame replacement windows.

Pocket replacement windows can be used in projects where the window frame is not being taken out, is in good condition and properly leveled.

The size of your window will also play a factor in which style of window you should purchase. Replacing a window with a choice that is the same size will make a pocket replacement window more likely. But, upgrading your window to a larger size will require uninstalling the previous frame and creating a new frame to fit your larger window as part of a full-frame installation. Thus, a full-frame replacement window will be needed for the job.

Removing the Old Frame

Using a full-frame replacement window, as the name infers, typically requires replacing the existing window frame, sashes and screen. This can usually be done with a utility knife, screwdrivers, pry bar, hammer, putty knife and circular saw, depending on your current window.

To safeguard your home exterior trim when uninstalling the frame, place a block of wood between the wall material and window, and then use a pry bar to remove the previous window trim.

Full Frame Window Options

Two window options can take care of your needs when doing a full-frame window installation: nail fin windows and block frame windows.

Nail fin windows are frequently seen in new construction projects, or any remodel where the walls will be exposed to the frame (studs). These windows feature a thin piece of metal extending from the window itself that follows around the outer edges of the window frame. When installing the window to a new frame, this nail fin attaches the window directly to the house’s studs and is unseen between the interior and exterior of your home.

Adding a nail fin window can be hard work and may require the addition of a new window frame or removal of siding so the installer can attach the nail fin to the studs. Nail fin windows are better to install in new construction —for example, when adding a room to your house — as the window is placed before the rest of the wall is finished around it. Plus, if you are wishing to install a nail fin window to a present wall in a section of the house where a stone or brick exterior would also have to be replaced, the job might not be worth the time demanded.

Block frame windows offer a choice for situations where nail fin windows would be more difficult to install. These windows are built without a nail fin and are designed to be placed inside existing window flashing — the section of the window that includes material to prevent water from entering into your walls — with minor new construction work. This makes block frame windows a standard replacement for a number of older homes that presently have a window structure in place or houses with siding or brick exteriors that would otherwise have to be harmed or removed to add a nail fin window.

Using Your Existing Frame

Replacement pocket windows are slightly different than full frame replacement windows and are built to fit inside an existing window frame. While the existing window sashes and exterior stops of the window should be taken out for the new window to be installed, pocket replacements allow homeowners to keep the original frame, trim, siding and casing.

Just as with full-frame window replacement, the wall exterior surrounding the window opening will play a role in how the pocket replacement process works, this time with fewer steps. Unlike full-frame replacement window removal, much of the existing sash, hinges and operating hardware will be adjoined with screws that must be taken out before removing the head, jamb and sill-stops with a pry-bar. Like the full-frame replacement window, adding a piece of wood to safeguard your wall exterior when uninstalling the old window is a sensible way to help defend against any incidental damage.

After pulling out the existing sashes and inspecting and readying the opening, the replacement window can be placed into the opening and existing frame. Make sure to plumb, level and square the window at each step of the installation to ensure a proper, balanced fit.

Consult with a Professional Installer

The requirements required to replace a window in an existing wall need a clear understanding of your design goals and an exact installation of your window. You can find detailed step-by-step installation instructions based on both the style of window, as well as the type of window opening, at install.pella.com.

Even with these detailed instructions, a number of homeowners discover that the possibility of accidental damage to their home — as well as the time, price and labor required — make window installation a project they’d rather not handle. Meeting with a professional home window installation expert, like the staff at your local Pella showroom, brings the technical knowledge and know-how to do the job right.

No matter where you are in your home window replacement plans, call a Pella professional today. Even if you are considering replacing a home window on your own, a window installation professional can help determine what installation method is best for your home and discuss installation approaches.

Schedule a free consultation to find windows and doors for your home.