Should wood subfloor be removed before putting in concrete base for bathroom.?
Question:Building NOT slab foundation. We put a wood subfloor in entire 20 x 24 building. Found out we need a concrete subfloor in the bathroom. Shower is already installed. If the wood subfloor is not removed, will the floor be too high to join the bedroom floor? Is it a problem that the shower is installed on the wood subfloor? Thanks!
Answers:
I just refinished my bathroom and this is what I did:
- Floor Joists
- 3/4" exterior grade plywood (at least 5/8" needed), glued to and screwed to joists
- Dryset mortar or latex-modified thinset mortar
- Hardie backer board (1/4" or 1/2", 1/4" is actually stronger): mortar above is used to adhere backerboard to plywood; cement backerboard is screwed into plywood using special screws available at Home Depot or Lowes.
- Seams between backerboard pieces are filled with same mortar you will use for tiling and cement board mesh tape
- Then use latex-modified thinset mortar to set tiles
- Use latex-enhanced grout (sanded if grout lines are 1/8" or more, unsanded if grout lines are 1/8" or less)
Here are more instructions on their web site:
http://www.jameshardie.com/backerboard/...
Good luck!
1/4" hardie backer -if 1 1/8" sturdifloor plywood
3/4 ply wood floor? you may get by w 1/4 backer board
Yes! Yes! Yes! remove that wood! From our experience, wanting to save time and a few bucks on plumbing pipes and fittings, we didn't move the sub-floor.
Guess what, a few years later, we are getting ready to tear the concrete out, remove the wood and start over because the natural moisture and humidity weakened the floor due to rot.
If you don't remove it, climb under there and re-enforce all the joists with pressure treated and block it up good!
Slightly off topic, but don't use laminate in the bathroom either. We did in another bathroom and it ruined too. We also put laminate on concrete that was cured about 6 months and it buckled up too.
The current building codes frown on any concrete to wood direct contact due to the way concrete holds water. This can cause rot and mold. You might want to incorporate backer board (the cement board that you buy at hardware stores that is 3 ft by 5 ft). Some backer boards are treated or made out of special materials to withstand the water.
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