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

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

When it comes to home repair tasks, few choices can produce a more dramatic impact than replacing your home windows. But while many other improvements can be taken care of with a little work and a good blueprint, replacing a home window demands significant work and a piece of technical knowledge.

As a result, replacing your windows is no easy task. You’ll want to know what type of window you’ll need, the specific plans required for replacing the window based on the size of the opening, and what items it will take to build the right fit for your new window. Here are a few concerns you may want to think about:

What is Your Frame’s Condition?

The condition, or even presence, of the window frame is the first major factor in matching the right type of window to your replacement plan. If you are constructing a new window frame, removing a damaged frame, or otherwise pulling the wall down to the studs, look for new construction windows, also known as full frame replacement windows. Pocket replacement windows can be installed 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 kind of window you should use. Replacing a window with a window that is an equal size will make a pocket replacement window easier. However, upgrading your window to a larger size will require uninstalling the previous frame and building a new frame to fit your larger window as part of a full frame installation. That means a full frame replacement window will be required for the job.

Removing the Old Frame

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

To cushion your home exterior trim when taking out the frame, place a block of wood between the wall material and window, and then use a pry bar to clear away the previous window trim.

Full Frame Window Options

Two window options can meet 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 project where the walls will be pulled to the frame (studs). These windows have a thin piece of metal connected to the window itself that runs around the perimeter of the window frame. When affixing the window to a new frame, this nail fin attaches the window directly to the house’s studs and is hidden between the interior and exterior of your home.

Installing a nail fin window can be both hard work and may demand the construction of a new window frame or removal of siding so the builder 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. Also, if you are wanting to place a nail fin window to a current wall in a part of the house where a stone or brick exterior would also have to be removed, the task might not be worth the effort required.

Block frame windows bring a choice for jobs where nail fin windows would be more cumbersome to place. These windows are built without a nail fin and are designed to fit inside existing window flashing (the area of the window that has material to prevent water from entering into the walls) with minor new construction work. This makes block frame windows a standard replacement for a number of older homes that currently have a window structure in place or houses with siding or brick exteriors that would otherwise have to be harmed or removed to place a nail fin window.

Using Your Existing Frame

Replacement pocket windows are slightly different than full frame replacement windows and are designed to be added inside an existing window frame. While the existing window sashes and exterior stops of the window should be removed for the new window to be added, pocket replacements allow homeowners to maintain the original frame, trim, siding and casing.

Just as with full frame window replacement, the home exterior near the window opening will determine how the pocket replacement process works, but with fewer steps. Unlike full frame replacement window removal, most of the existing sash, hinges and operating hardware will be adjoined with screws that must be uninstalled before clearing away the head, jamb and sill stops with a pry-bar. As with the full frame replacement window, placing a piece of wood to shield your wall exterior when uninstalling the old window is a smart way to help avoid any unintended damage.

After taking out the existing sashes and inspecting and prepping 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 have the best chance for a proper, balanced fit.

Consult with a Professional Installer

The requirements required to replace a window in an existing wall need a clear knowledge of your design plans and a specific installation of your window. You can review detailed step-by-step installation instructions based on both the kind of window, as well as the type of window opening, at

Even with these detailed instructions, a number of homeowners discover that the chance of accidental damage to their home (as well as the time, price and labor demanded) make window installation a project they’d rather not undertake. Working with a professional home window installation expert, like those at Pella of Woburn, offers the technical knowledge and know-how to do the job correctly.

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

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