I'm currently remodeling a house that has 2x6 floor joists and two layers of subflooring (5/8" + 5/8"). I assumed that with a total of 1 1/4" subfloor, the contractor wouldn't need to trim the joists much. But the contractor mentioned needing to taper them 2" instead. The shower is 3x5 feet and has a drainage slope that needs to be 5 feet long. How much total depth do I need for my curbless shower from the flooring? What materials and thicknesses should I consider?
3 Answers
Based on what I've seen in some YouTube tutorials, it looks like you might only need to take out about 3/4" of the subfloor. You can add blocking that’s 3/4" lower than the joists, then put a new subfloor on that blocking. This way, you create a level surface with the joists and can lay down the curbless shower pan on top. Easy fix!
For a slope, you really only need a quarter inch per foot. So for a 5-foot slope, that means about 1 1/4" total. Instead of cutting the joists, I usually just raise the bathroom floor by adding layers of cement board. It's not a big deal if the bathroom is a bit higher; I didn't even notice it in my own bathroom with a rug in front of the door!
You probably won’t need to modify the joists at all! If you go with 3/4" plywood plus 3/8" for the tile and another 3/8" for thinset or Ditra, you'd be looking at around 1 1/2" total. You can just add 1/4" plywood to the rest of the bathroom to balance it out. Seems straightforward!