Replacing Windows in Stucco Homes: 6 Things to Keep in Mind

Stucco is one of those materials that has stood the test of time, as the mixture is affordable, aesthetically pleasing, and durable. Removing doors and replacing windows on a stucco home, however, requires a bit of masonry expertise and specialized tools. If you’re looking to make exterior improvements to your home, keep in mind these tips when you’re replacing windows in stucco.

1. You’ll Need Special Tools to Cut Through Stucco

Stucco is the result of mixing Portland cement with lime, water, and a bit of sand, essentially making it solid rock layered on top of the wood framing of your house. Stucco siding is popular in warmer climates, in particular, because it insulates both hot and cold air.

While the vertical nature of the cladding limits the thickness to about an inch, stucco is still a very hard material to cut without diamond blades, so you’ll want to hire a local window contractor to do this work. Most contractors will use a gas-powered concrete saw to etch around the windows, but if you’re doing a smaller DIY window replacement job, you can get by using a hand grinder with a concrete blade. 

This work is messy and requires a fair bit of muscle, as do all concrete jobs, so bring your elbow grease, an N95 mask, and leather gloves to the work site or hire a concrete repair contractor.

2. Stucco Windows Need Special Treatment

On a house with wood siding, the framing of the windows is usually thick header boards made of wood. But on a stucco-sheathed home, the additional weight of the walls requires a sturdier support mechanism. 

If you’re replacing the windows on your stucco home as a DIY project, the additional width that you’ll need to cut out of the stucco to access the main steel beam across the top of the window makes this process quite a bit more effort than an insert. These pieces of steel are often rusted out and will need to be removed first.

3. There Are Two Main Replacement Techniques 

When it comes to replacing windows in stucco, there are two tried-and-true techniques to consider: insert replacement and architectural window replacement.

Insert Replacement Method

The insert method is not only the most affordable option for replacing stucco home windows, but it also requires the least amount of exterior changes. 

First, the window installer or contractor will measure for replacement windows and order a window that's slightly smaller than the original. During replacement, your pro will cut out the existing window and insert the new one without changing the stucco, framing, or seal. The benefit is a straightforward method, but it can potentially make the window look a bit smaller or less seamless than a more custom approach. 

Architectural Window Replacement Method

This method is best when you want it to match the house's original architectural intent and construction. Architectural windows require a more labor-intensive replacement process, beginning with stripping the stucco from the wood studs and removing the old frame. Next, the new window will be nailed directly to the studs. A few layers of stucco will cover the flange, ensuring a watertight seal. 

Matching the new stucco to the original requires a bit of extra care. Therefore, you may want to leave this part to a contractor who can handle a more time-consuming expert install and finish the project with the right tools and know-how. The result is worth the additional considerations as it keeps the original window size intact and creates a more finished look.

4. Wall Removal Is Part of the Process

To access the original framing and remove the window entirely, you’ll need to use masonry tools to cut out and remove about five inches of old stucco wall all the way around the window. The stucco will be mixed with a wire lathe base and the nails used to hold it up, so you’ll encounter additional hazards during this partial wall removal and need to proceed carefully. 

If you’re working on a house that was built prior to 1978, you’ll also have to deal with the potential for exposure to lead, so it’s essential you know about lead paint safety, understand the importance of wearing proper PPE while you’re creating dust, and wash all clothing before interacting with anyone else.  

Retrofitting an existing window in a stucco house can result in requiring the removal of rock or brick that surrounds the opening. Depending on how your house was designed and built, brick or rock may frame the window and, thus, need to be removed. A window retrofit is hard labor and often out of reach for the average DIYer, so you’ll want to hire a window installer for the gig. 

5. There Are Two Types of Stucco Window Frames

Stucco flange and nail flange are two common types of installation methods, and the right process for your home may come down to what shape the existing window frame is in and if you need additional waterproofing done.

Stucco Flange

Stucco flanges—also known as a flush-fin—are commonly used when a window frame needs a flush installation on a flat exterior surface. A pocket installation fits the new window into the existing frame, saving time since the stucco siding and old frame will remain intact throughout the process. Before installing, remove old sealant and debris from the wood frame. This type of installation is also ideal for windows with no structural deterioration or water damage and will be properly sealed and maintained to be extra waterproof and weather-resistant.

Nail Flange

Nail flange or nail-fin window frames add an extra weather barrier to your window with a seamless outer perimeter around the window. The nail flange provides additional window support and helps prevent warping, as well. It attaches via pre-drilled fastener holes into your home's framing during installation. Because a nail flange is placed about 1/2- to 3/4-inch under the siding, the surrounding stucco material must be replaced and matched to the existing siding after the new window installation.

6. Priming and Painting Come Last

Assuming that you’ve gone the route of replacing old windows with an architecturally accurate replacement, the stucco contractors will have created a fresh bed of raw cement around every one of your windows. To match the existing texture and properly seal your home up against the elements, you’ll need to prime and paint the stucco siding around the window. 

You’ll also need to touch up the walls on the inside of your home when done, so brush up on your home painting tips before you start or hire an interior painter. If you’ve opted for the insert method of replacing your old windows, you’ll still have damage to your exterior and interior trim that, while minimally invasive in comparison, will require a layer of primer and paint to finish the job on both sides.

Lacy Brunnette contributed to this piece.