Window in a Shower: Why It's There, Waterproofing, and Removal

A window in a shower brings natural light to a confined space, but it also brings major problems. Though windows can withstand the elements, especially moisture, that's just on the outside.

Moisture inside a window leads to serious, costly damage to the window and the house itself.

Learn why there is a window in your shower, waterproofing options, and if removing the window is a good idea.

Why There Is a Window in Your Shower

Your home likely has a window in the shower because the shower stall was once a bathtub.

Older homes often had full-size windows placed in the bathtub alcove area. The configuration was acceptable because bathers don't usually splash water above the height of the bathtub rim.

As bathtubs fell out of fashion, bathtub alcove areas were frequently converted to showers. The tub basin and controls remained, and a vertical water supply line was added to bring the showerhead to around 80 inches high.

With a tile surround installed inside the enclosure and a shower curtain added, the tub was ready to be used as a shower—though imperfectly with its water-sensitive window.

5 Ways to Waterproof a Window in a Shower

Waterproofing techniques limit water intrusion and slow damage to the wall. All solutions are temporary—for example, draping a shower curtain in front of the window. Ultimately, the best solution for a window in a shower is to remove the window.

Add a Shower Curtain on the Window Side

Add a shower curtain on the inside of the stall as a fast, inexpensive way to prevent water from reaching the shower window.

On the exterior wall, run a shower rod from wall to wall in the bath alcove. Place a shower curtain on the rod.

Remove or Replace Window Trim

Remove any wood trim and bring the tile up to the edge of the window opening.

Water-logged wood window trim will eventually develop rot. Trim also provides an easy avenue for water to enter behind the window.

Check the caulking around the window trim periodically for signs of wear, and wipe the window sill dry after each shower to help guard against rot.

Fix or Replace the Window Sill

Replace wood window sills in the shower with tile or solid surface material to slow window rot.

Anything flat in a shower pools up with water. Shower window sills collect water and send it running down into the wall.

Installing tile on the window sill is a DIY-friendly option. Even better is solid surface material, which eliminates seams. One continuous piece of solid surface material can run from end to end, instead of the numerous grouted seams found with tile sills.

The material should be sloped down toward the shower to promote drainage.

Install a Vinyl or Fiberglass Window

Replace a moisture-prone wood window with a vinyl or fiberglass window. All parts of a vinyl or fiberglass window are water-resistant.

Install a Glass Block Window

Install glass blocks in place of the current window to bring in diffused light, ensure privacy, and provide better moisture protection.

Glass blocks are heavy. One glass block measuring 6 inches square by 3 inches thick weighs more than 3 pounds. Due to the weight of the glass blocks, the wall will likely require additional support. Because glass blocks have only a minimal R-value (about 1.75), exterior use is limited to temperate climates.

How to Remove a Window in a Shower

If you have a window in your shower, consider removing the window and closing up the space.

Rebuilding the wall cures the moisture problem and lets you fix existing water damage to the wall studs. Moldy insulation can be removed and replaced. Here's what it entails:

1. Remove the tile surround, window, casing, and trim.
2. Remove all of the moldy insulation.
3. Support the exterior wall.
4. Remove the wall studs on each side of the old window.
5. Remove the partial studs below and above the window, as well as the header stud.
6. Assess the extent of the damage for other wall studs that need to be replaced.
7. Install full-length wall studs.
8. Insulate the wall with fiberglass or mineral wool insulation.
9. Add a 4-mil or greater vapor barrier on the inside.
10. Add drywall or cement board on the inside.
11. Add siding on the outside.

What if There Isn't a Window in My Shower?

If you need more natural light and some ventilation and have limited room in your bathroom for a new window, putting one in the shower may work best.

It costs about $100 to $900 to add one vinyl window and $500 to $1,500 to add a fiberglass window. However, costs will vary and likely be higher since the window may need to be inserted into an interior tile wall and need extra waterproofing.1

Consider the placement of a new window in a shower. Ideally, the window should be on a wall near the showerhead but higher than the showerhead to keep it drier. Consider narrow clerestory or transom windows that fit well higher on a shower wall above the showerhead while providing adequate privacy, but may or may not open for air.