Who Replaces Window Sills?

Replacing window sills isn’t hard but leave it to the pros

Angie Hicks talks to the pros about the work being done
Photo: Ian Tuttle / Angi
Angie Hicks talks to the pros about the work being done
Photo: Ian Tuttle / Angi
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Over time, the elements will catch up to your home’s window sills. Before you know it, they can leak, break, or rot, and you’ll want to replace them quickly before more damage is done. While replacing a window sill is something you can do yourself—if you have the experience—hiring a window repair company with licensed contractors on staff will guarantee it’s installed correctly and stays water and air-tight. Learn more about who can tackle the job of replacing window sills.

Benefits of Hiring a Window Repair Company for Replacing Window Sills

Because window sills are flat with multiple joints where molding and sash tracks end, they are subject to decay from long-term weather extremes and moisture. Sills can crack, rot, or break. If left untreated, this damage could become so bad that you’ll have to replace the entire window frame in addition to the sill. The cost to replace a window frame is $380 on average.  

To tackle this project, you’ll want to enlist the help of a window repair company. Window repair companies can handle every aspect of window frame replacement, including just the sills. Aside from having the knowledge and experience needed for the job, these professionals have the necessary equipment to create, place, and seal window sills properly to prevent moisture and air from coming in. While hiring a local window repair company will cost more in labor, it guarantees the job is done correctly and gives you peace of mind. 

Can I Hire a Handyperson to Replace Window Sills?

An experienced handyperson can also replace window sills. If you go this route, you’ll want to find out if they have experience fixing or replacing all window components. A handyperson can typically fix windows that are a standard size. However, if your windows are not standard, you may want to hire a window repair company to do the job. 

Although considering the price difference between a window repair company and a handyperson is an important factor, you’ll want to prioritize who has the most experience with this type of project.

Can I Hire a Carpenter to Replace Window Sills?

As with a handyperson, you’ll want to ask the carpenter about their experience fixing or replacing all window components. However, many carpenters do have the technical knowledge necessary for this project, as long as your windows are the standard size.

How Do Window Repair Companies Replace Window Sills?

A professional installing a new window sill
Photo: ftwitty / E+ / Getty Images

A window repair professional will first examine the frame’s construction. This includes noting the material used to make the sill. If it’s wood, a pro will also need to know the sill’s capping or cladding material, which is a protective barrier made from vinyl, aluminum, or fiberglass.

A pro will uncover the window sill and the rest of the frame to identify the damaged areas and remove whatever needs to be replaced before remaking a new sill to fit the frame. Before installation, they’ll fix any areas around the sill that need repair and seal the area. The newly installed sill should last for several years with no issues. 

How Much Does Replacing a Window Sill Cost?

On average, window sill replacement costs between $150 and $700 if you want a professional to handle the project. The cost varies by material and window size, with aluminum sills being the least expensive and wood sills the most expensive. Window sill replacement on a wooden bay window could be as much as $1,100.

Can I DIY Window Sill Replacement? 

There are several types of window frames, including wood, aluminum, and fiberglass, so you’ll want to make sure the sill matches the material. If you have vinyl or wood, you’ll also need window capping over the sill. If you have enough DIY experience with replacing window frames, replacing sills is not difficult. 

Window sill repair costs are about $200 to $300. The price will depend on the cost of labor, materials, and the size of the window sills. While window sill repairs are not as costly if you tackle the job yourself, the margin for error is greater, particularly if you’re a novice. 

Window sills must sit at the right angle to keep moisture from coming in. Not using enough sealant or caulking or incorrectly positioning a sill can lead to damage from the elements and yet another replacement. If you’re replacing a sill on a second or third floor, doing this work on a ladder can be dangerous. So, the extra cost to hire a pro is probably worth it. 

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