Installing tile in bathroom with existing vinyl sheet flooring
#1
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Installing tile in bathroom with existing vinyl sheet flooring
I have a small 2nd floor guest bath (6.5'x5') to which we're looking to install new 13"x"13"x7/16" porcelain tile. The existing floor has vinyl sheet flooring, some type of 1/4" underlayment, and then the subfloor.


I already took the the vinyl sheet out. However, my question is...should I leave the existing 1/4" underlayment & replace it with 1/4" hardibacker board OR should I remove the existing 1/4" underlayment & then install hardibacker?
Thanks!


I already took the the vinyl sheet out. However, my question is...should I leave the existing 1/4" underlayment & replace it with 1/4" hardibacker board OR should I remove the existing 1/4" underlayment & then install hardibacker?
Thanks!
#2
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The 1/4" ply needs to go! If the floor is stiff enough - just replace it with 1/4" cement board. Often it's prudent to add 1/2" ply first to stiffen the floor as that can go a long way to prevent cracks in the grout or even tile. Most like to see 1.25" thick sub floor under tile.
The 1/4" ply needs to go! If the floor is stiff enough - just replace it with 1/4" cement board. Often it's prudent to add 1/2" ply first to stiffen the floor as that can go a long way to prevent cracks in the grout or even tile. Most like to see 1.25" thick sub floor under tile.
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The 1/4" layer needs to go. What does that leave? What's the size, spacing and unsupported span of the floor joists?
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I took out the underlayment, and it leaves he subfloor with all the fun staples (removing those today). Looks like 3/4" -- there's a stud to the left of the register, one to the right of it, and one 16" to the right of it.





#8
Many times what looks like 3/4" is actually 5/8" and an additional layer will be needed. Drill a hole and insert a coat hanger and see how deep the cavity is to figure out the joist size. The span will be determined by looking a the direction of the span and where the walls are located in the room below.