How to Install a Tile Window Ledge Treatment
**Our honesty policy: This post may contain affiliate links and I may be compensated if you make a purchase at no extra cost to you. Some are, some aren't--I do some comparison shopping. The important thing is you will know exactly what we are talking about. Drop a note/comment if you have any questions on the products as these are materials and tools we use on our own projects.
Not your average window ledge hiding behind the curtain.
What is hiding behind that curtain besides a window? Is it a ho-hum drywall box or a surprising fabulous window sill? If you learn how to install a tile window ledge treatment you are adding some unexpected eye candy to a room.
Before explaining how to install a tile window ledge treatment you need to decide on a few finishing touches:
Determine your design. Are you maintaining a tile theme throughout your house? Do you want a stone going across the full length of the ledge?
Another consideration is the look and feel you want for the front exposed edge. Should it show a bullnose* rounded, polished edge? Should it be a squared off polished edge? Want to forget about polishing all together and select a sleek modern metal edge finish?
Side tangent here:
When you are considering the finished edge, your decision may be influenced by your answer to the first question. Depending on your tile design you may encounter a difference in tile thickness. For instance, if you look close at the picture below you’ll notice the travertine is ½” while the marble tile is ⅜”.
One way to hide the exposed front edge difference is by using a finish edge like Schluter’s JOLLY. This way the front edge of the tiles are hidden behind the metallic edge. It also comes in many different colors to match your look and feel.
The Schluter Jolly covers up the difference between the ½” travertine and the ⅜” granite tiles.
Either way, you’ll have to slather on extra mortar on the thinner pieces during installation, ensuring the top surface stays level.
The difference on the front edge is pretty negligible. A difference in the top level is not as forgiving.
See, it isn’t so bad if you are standing further than six inches away.
–end tangent
Third, will you incorporate trim around the window extending the ledge past the drywall? There are a couple reasons to add trim:
- Looks. I personally liked the extra panache of the trim along with the pop of white against the paint on the wall and the various color tones of the tile.
- Hiding a curved wall. The larger the window the more likely it is to have some sort of curve along the front edge. If this is the case, you can place a shim to straighten the front edge, essentially hiding the gap behind the trim.
- Trim has the added bonus of increasing the size of your window sills for your window-loving plants and cats.
All of these questions need solid answers before moving on to the measurement step. If you are adding trim your measurement is deeper by the width of the trim. Likewise, if you opt for a metal finish edge you’ll need to subtract the width of the vertical piece of metal from your measurement.
A cross section view of adding trim along the ledge as well as a metal finish edge. Your choice of finishes will need to get taken into account when taking the final measurements.
This is why I install any trim before measuring the final size of the tileable space. It is harder to mess up a measurement when the trim is already attached. This especially true if the trim requires shimming.
Once you have all your design decisions made and any trim in place, measure off the space and make any adjustments needed for the finish edges.
At this point, consider installing leftover Schluter KERDI down on the larger/longer windows.
Schluter KERDI is the orange stuff on the window ledge.
If you are not familiar with KERDI from Schluter or similar type product, here is a basic summary in two sentences. It is a waterproof membrane with felt type substance on either side. Mortar does not stick to a plastic membrane, but it thoroughly embeds itself into felt, waterproofing below the surface. More on KERDI here: Install Schluter KERDI Like a Boss (and a Nerd).
Unlike cement backer board in showers, window sills are mostly just a sheet of drywall. It’s not like there is constant water on your window ledge–you’re probably going to notice and instantly clean up a spilled cup of coffee or glass of wine. KERDI is just extra insurance if something spills and sits for days (I can imagine a kiddo “helping” me water a plant while I am occupied elsewhere).
KERDI also has a small amount of crack bridging capabilities. FYI, it is intended for the gaps between cement backer board sheets in a shower. It is not intended as an ANSI A118.12 approved crack isolation membrane. But as this is my own blog, it seems like it is a heck of a lot better than nothing with all the popping and creaking of my house on any given day. Just don’t expect Schluter to back this usage of their product under any warranty. I’m not, but for the amount of popping and creaks the house let’s out when the temperature changes, installing KERDI is just a little extra peace of mind.
When I install KERDI I like to overlap it onto the trim as well. If I’m going through the effort to put it down to ward off movement and popped tiles, might as well add it over the trim. This is especially true if you shimmed the trim.
Next, solidify the design of the window ledge. You can mock up the final design using Paint or some other photo enhancing software or app.
Now it’s the much anticipated time to break out the wet saw! If you opted for a bullnose edge you’ll want to fabricate the edge while the tiles are full size…larger pieces are safer than smaller pieces. Read this post for more sanity saving tips for creating a finished edge yourself.
Once you have all the pieces make sure to dry fit all the pieces of tile. This increases your odds of NOT running to the wet saw for “one last cut” while thin-set is drying.
You can see all the tiles prearranged ready for installation after it was dry fit on the window ledge. You can also see where the Schluter KERDI extends over the top of the white trim.
Next, mortar all the pieces in place. This is when you are competing with the thin-set drying. Keep tabs on how level and straight everything looks as you install each piece. Finish installing everything in one sitting so you don’t end up with an “oops” piece you would have noticed had you finished it all together.
After the thin-set dries, grout and seal the grout (unless you use sealer as your liquid mix in the grout).
Enjoy!
Yes, you deserve a beer float and bacon after a day of intricate tiling.
If your windows are simple drywall boxes, an update with some eye popping tile can breath some class into a room. If you have already remodeled major spaces in your home, a window ledge is just a small project. As mentioned throughout, when you install a tile window ledge treatment it can use the rest of your leftovers from the remodel of your bathroom or kitchen. All it costs you is your time.
*If you opt for a bullnose edge check out these directions as well as the sanity saving tips. Remember to stay safe and enjoy your new tile window sill ledge treatment!
