bathroom help

tservice · 02-14-2009, 10:54 AM

I am going to be removing the linoleum and putting down tile. Do I need to remove the 3/8 subfloor or lay my backer board on top of that. My concern is the treshold height.
Thanks

Bob Mariani · 02-14-2009, 11:02 AM

We need to know these things first. What size joists do you have? What are their span? What is the joist spacing? Next, what sub-flooring do you have? You want 3/4" T & G plywood at a minimum. After that 1/2 exterior grade plywood and them 1/4" CBU or Ditra. And yes the 3/8 should be removed.

angus242 · 02-14-2009, 11:07 AM

What kind of tiles, natural stone or ceramic?
3/8" underlayment. What's the subfloor thickness?
Do you know the size, length and spacing of your joists?

While height may be your initial concern, you need to have a certain subfloor thickness (based off some of the questions above) that ultimately determines the height. Not aesthetics. You have underlayment options which may help overall height but if you want your installation to be successful or last, there are certain steps you need to follow.

tservice · 02-14-2009, 01:06 PM

sub floor is 5/8 joist are 2*10 on 16"center, this is a small bath

Bob Mariani · 02-14-2009, 01:23 PM

Remove the 3/8" Install new exterior grade 1/2" plywood. Do not line up the seams. Leave 1/4" gap along the walls and 1/8" gap at all seams. 1/4" cement backer board (CBU) and tile. If it is second floor then add waterproofing also. Use Redgard or similar product.

angus242 · 02-14-2009, 02:02 PM

Quote:

Originally Posted by tservice

sub floor is 5/8 joist are 2*10 on 16"center, this is a small bath

We don't know the length of your joists but regardless, you are at the very bare minimum. Personally, I'd like to see an additional 5/8" exterior grade plywood over the subfloor. If height is truly a concern, consider Ditra as your underlayment instead of 1/4" CBU.
5/8"T&G + 5/8"PLY + 1/8"Ditra = 1 3/8".
5/8" T&G + 1/2" PLY + 1/4" CBU = 1 3/8".

I'd go for the stronger floor with superior underlayment.