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My drains are set and my water pipes are in place and now I am so ready to start putting things back together! Before I start anything else, I need to level the bathroom subfloor. When I removed the tub and shower I was left with this…

unlevel bathroom subfloor where shower used to be

and this…

unlevel subfloor where bathtub used to be

I was left with big holes in the bathroom subfloor where the tub and shower used to be. When the previous owners remodeled the bathroom forever ago, they added additional subfloor for God only knows why. To fix this I have two options: 1) remove the additional subfloor, or 2) build up the subfloor to match that rest of the bathroom. Option one sounds like way too much work, so I will be building up the subfloor.

Choosing the correct subfloor

Just like everything else in this process, there are many options with subfloor and I will not go into all of them. Here is a good website that describes the different options. I needed to choose plywood that matched the existing bathroom subfloor so that I would have a level surface to start my tiling.

I found the plywood to be 5/8″ thick, but when I went to Home Depot, I could not find it. Turns out that 5/8″ is a nominal measurement, but the actual measurement is 19/32″. Sure. Makes sense. Why wouldn’t it be? This is true with all plywood. Here is a great chart if you ever find yourself needing plywood with a certain thickness.

Cutting the subfloor

I grabbed my skill saw, made some measurements, and started cutting. Then I found something I really suck at…

cutting bathroom subfloor first attempt

I tried to cut the subfloor to fit the angle in the floor, but I was way off. I ended up having to cut off the end and try again.


adding pieces of subfloor to level bathroom floor

My second attempt was much better. And by second attempt, I mean like 20 something, as I had to cut over and over again to get the angle right. Additionally, I had to make sure to leave a bit of a gap to allow for expasion of the wood. Like a glove!


There was about a 4″ gap between the subfloor and the wall. I filled the gap with 2 more pieces of plywood.


assistant helping me to cut subfloor

I wasn’t able to get the greatest picture because my assistant for the day was a little needy, but you can see it in the background.


measuring to cut hole for tub drain in subfloor.

Next, I cut the hole for the bathtub drain in the subfloor. I found the distance to the center of the drain and cut a 10″ square hole to allow for access to the drain when hooking up the tub.


adding bathroom subfloor with hole for tub drain

Thirtyish swearwords later and I was ready to cut the subfloor for the shower.


bathroom subfloor for shower

After many, many attempts, I reached the status of good enough.


As I mentioned before, I am using the Schluter-Kerdi shower base system and drain. The drain requires a 5″ circular hole to be cut in the plywood.

For this, I measured the distance to center drain from each wall. Then I used a 5″ hole saw to cut a perfect circle in the subfloor.


hole for shower drain cut in bathroom subfloor.

This one took the least amount of swear words. The only thing that sucked, was the saw kept catching on the wood and it would really hurt! I had to start the drill incredibly slowly, then very slowly increase the speed so it would cut.

Schluter kerdi drain in shower subfloor.

Finally, I checked to make sure the drain would appropriately fit into the hole and, by God, it did! Can you believe it?


Let’s get anchoring!

liquid nails used to anchor subfloor

I added liquid nails to the smaller pieces of plywood where it would be harder to anchor to joists.


liquid nails before anchoring shower subfloor

And did the same thing with the shower area because there were not enough anchor points as well.


Then I marked the joists and used a crap ton of 2″ screws to anchor the bathroom subfloor to the joists.

checking level of subfloor

Finally, I checked to make sure that the floor was level.


Here is the finished bathroom subfloor… kind of. My bathtub finally came and when we moved it into place I nearly cried. The drain was too close to the wall and the bathtub base wouldn’t cover the hole. For F*&! sake… My next post will most likely be on relocating the bathtub drain I guess.

I started this blog in the hope of inspiring other people to try something new, especially if it is unexpected. If you like what you are seeing, please like, comment, or share! Thanks for reading!