How to Install a Window in Basement Bathroom

Do you have an old window that needs to be replaced?  Today I am going to show you how I am updating an old aluminum window and installing a new double pane vinyl window in our basement bathroom.  Thanks to DAP for sponsoring this post, all opinions are ours — see our full disclosure policy here.

Our Birch House is an older home, so we’ve been doing plenty of updates to modernize the space. From updating the mantel and fireplace, to installing new flooring and a new kitchen and pantry, to getting rid of the pink bathtub — it’s been a few years of projects but it’s coming together! (We’ve put in a lot of work in the yard, too!)

This project is in our basement bathroom, which we’ve been working on for awhile now. The last thing we showed you was adding the cement board around the bathroom for the new tile.

Before we get too much more into the bathroom remodel, it was a good time to replace the old aluminum window with a new double pane vinyl window. The old window was installed in the 50’s and is not very energy efficient.

Installing window in basement bathroom

Luckily, our window isn’t over the vanity/sink area like this one — but this sliding mirror was a clever solution if we did have that issue!

Installing a Window in a Basement Bathroom

What is the cost to replace an old window?

$120 for the new vinyl Jeldwen window and DAP materials to make it weather tight.

How much time does it take?

It took us about 3 hours from start to finish including

  • removing the old aluminum window
  • cleaning the window space
  • installing the new window
  • caulking to make the window weather tight

How to measure the for the new window

Measure the height and wide on the outside and subtract 1/4″ to an 1/2″.  That will give you the final dimensions of the window.

For this new bathroom window, I ordered a vinyl window without fins on the sides because I was adding wood trim around it.  It took about a week or more to pick up the window, because it was a custom order.

Get our tips for picking new windows here.

What You’ll Need: Replacing an Old Window in a Basement Bathroom

Materials List

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Tools Required


How to Remove an Old Window and Install a New Window

1. Remove old existing window.

I had to cut out the frame with a metal reciprocating saw blade.  After making the cuts, I used the hammer to pry it all out.

Installing window in basement bathroom
If you have an old wood window and can remove it in one piece, here are some ideas for what to do with old windows. 

2. Clean and prep the window area free from dust and debris.

Remove any dirt, dust and old caulk from the old window.

Installing window in basement bathroom

3. Dry fit new window.

I made sure that the window I ordered fit in the space. Phew! Measure twice, order once!

Installing window in basement bathroom



4. Add wood trim.

Because this window is in the basement concrete wall, I added redwood trim. We like working with redwood because it’s a durable wood that’s naturally rot- and weather-resistant — we use it in almost all our outdoor projects, from our deck to our new raised garden boxes. (See redwood concrete bench, garden arbor, and pergola, too.)

I glued a redwood frame in place with DAP DynoGrip.  I needed something to easily to drill into to keep the window in place.

Installing window in basement bathroom

Installing window in basement bathroom

4. Level the window.

I used a small level to make sure it was level in the opening.  I was lucky, because the wood frame that I made was just right and I didn’t need to use shims to level it.

Installing window in basement bathroom

6. Test window to make sure it opens easily.

Make sure you slide the window open and closed to check that it operates after it’s level.

7.  Screw the new window to the wood frame.

I used 1 1/2″ screws to attach the vinyl window to the wood frame.  Just make sure the screw head is a flat head that doesn’t get in the way of the window opening and closing.

Installing window in basement bathroom

Then I covered the screw heads with the caps that come with the window. It looks nice and makes the window track easier to keep clean, too.

Installing window in basement bathroom


6. Seal with foam.

I used DAP Touch ‘N Foam to close all the gaps of the window both on the inside and outside.

Installing window in basement bathroom

Installing window in basement bathroom

7. Seal with Caulk

After the foam dried I used DAP Window Trim Caulk to seal off the outside of the window to keep the water out.

Installing window in basement bathroom

Related Reading: How to Install Craftsman Window Trim

Now I need to start working on the tile to finish off this bathroom! We’re still deciding on the finishes for this bathroom — we could do some fun moroccan style fish scale tile like this, or some modern hexagon tile… lots of options!

Stay tuned for more bathroom remodel to come — and you can see where this bathroom started here and how we installed the cement board here.

More DIY window updates:

Install A New Window In Basement Bathroom, How To Replace An Old Aluminum Window With A New Double Pane Vinyl Window #remodelaholic



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I am the husband of the amazing Cassity of Remodelaholic. I love to problem solve and to design and build things inside and outside the house to make life better. I am a professional Landscape Architect by trade and love the outdoors.

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