Stucco Window Leaking | What Now?

Stucco Window Leaking

If you have stucco on your home and noticed that a window is starting to leak or maybe has been leaking for awhile, then you will definitely want to find out what the problem is and how to go about fixing it.

I have fixed many windows with this same exact scenario and it is usually a result of one of two things... the window flashing or an issue with the stucco paper somewhere. Let's dive deeper into what to expect and run through a couple of examples to give you better insight on what might be causing the issue.

Is The Window Leaking, Or Is It A Problem With The Stucco?

The first thing you will want to determine, is whether the leak is coming from the window itself or somewhere under the stucco finish and base coats, where the waterproofing layers for both the window and the stucco are located.

About Testing: Testing will require you to be able to view around the window's framing, to get the best possible viewing area. Testing without being able to see around the window could give false results. 

It is easier to test for leaking if the drywall on the inside is removed from around the window, in order to see if there is water coming in. This will also provide insight on the relative condition of the plywood and/or framing, too.

The Window Itself: Testing the window itself can be fairly easy to do by taping off around the face of the window using a waterproof tape (vinyl, duct, etc.) and then covering the window with a thicker plastic, like a 1 mil plastic. This will ensure that the window is sealed off completely and when you spray water in that area, you will then look for any signs of leaking.

Tape Off Window

Just make sure that the tape is sealed to the window all around the entire perimeter and that the tape is also sealed to the plastic, as no water should be able to penetrate the barrier. If no water is observed after 3 - 10 minutes of a heavy shower from your hose, then pull the tape and repeat the process with an additional 5 - 10 minutes of water to see if the window is leaking.

If you do get water coming in with the window taped off, then it is highly probable that there is an issue with the flashing and/or paper underneath the stucco. You will have to remove at least 6 - 8 inches of the stucco around the perimeter of the window to see what is going on.

I do want to note that this is not a 100% foolproof way to determine if the window is leaking, it is just a quick test that has proven to work for myself and other contractors. A window specialist taking a look is always a good idea, when in doubt.

My Personal Experience:

In my personal experience, having done so many of these over the years, most of the issues caused by a leaking window on stucco walls is due to a flashing related issue, specifically the window flashing itself. It is either deteriorated, not installed or installed incorrectly, allowing water to get right in.

I have also seen the paper become deteriorated so bad that it crumbles in my hands when I go to touch it. Needless to say that it is no longer keeping water out of the wall.

Caulking Around Windows: I have heard many home inspectors, painters and other professionals recommend sealing the cracks on stucco walls and around windows to seal up any possible leaking points. While this does work in some cases, it will not work if there is a larger problem under the stucco base coat(s).

I usually just tell people they can caulk it if that is the route they want to go but if there is a larger underlying problem, then it will continue and will usually cause more damage in the long run due to the plywood/OSB, drywall and framing damage that could potentially occur down the road, making the fix a lot more expensive.

If Your Stucco or Window Flashing Is Leaking...

If you came to the conclusion that your window flashing or the stucco is the cause of the leak, then you will have to tear into the stucco and inspect all areas and materials around the window, in order to be sure that it is really fixed.

The General Procedure: This is done by removing the stucco around the entire window anywhere from 6 to 9 inches, in most cases, flipping the wire out of the way and pulling the paper back to get a better view of the window flashing. If you have a decorative trim molding around your window, then it will also have to be removed.

Break Out Stucco Around Window

Break Out Stucco Around Window

Patch Area Around Window

Patch Area Around Window

Install Any Trim Around Window

Install Any Trim Around Window

Once all that is removed, you should be able to see where the problem is stemming from and if it is the window flashing itself, then the window will have to be pulled (in most cases), in order to install new window flashing.

This is also a good time to look at the paper and verify the condition of it, in addition to the window flashing.

An Estimated Cost: I know that a lot of people will probably have someone perform this service for them and are wondering how much it will cost. I will give a very general price range due to many different factors involved.

I would say that in most cases, you could expect to pay someone $400 - $1800+ for a repair like this. That is a pretty large range, but some factors that affect the overall price of the project could be:

  • window location (ground level, cheaper vs third story, more expensive)
  • window trim (no trim, cheaper vs lots of trim, more expensive)
  • stucco system used (3 coat, 1 coat, EIFS, etc.)
  • stucco finish (one or two coat finish, two coat equals more money)
  • custom color matching services, expensive vs painting, cheaper
  • window size (smaller window, cheaper, large window, more money)
  • window condition (cleaning of old caulking, flange condition, etc.)
About the author

The Stucco Guy

My name is Ryan and I have been a licensed stucco contractor for many years and I feel that there is a huge "knowledge gap" when it comes to stucco, in particular. I hope you find the information here useful, and if you have a question for me fill out this Q & A form, so I can answer those questions better. Thanks for stopping by!

Leave a comment here or if you have a question that needs to be answered, fill out my Q and A form (link in author bio box above) to give me a clear picture of what's going on. Thanks for stopping by!: