Asked by: Saturnino Scheurlen
asked in category: General Last Updated: 27th May, 2020

Do you need plywood under cement board?

The Surface Below the Cement Board
Flooring: For ceramic tile floors, the cement board usually rests on a plywood subfloor (minimum 5/8-inch-thick exterior-grade plywood or OSB). (Some cement board products may not require the underlying membrane if the seams are properly waterproofed.)

Click to see full answer.


Hereof, do you need mortar under cement board?

Thinset is absolutely required beneath backer-board on a floor. Also, backer-board provides no structural strength at all. You can not install it directly over a 1x subfloor; that is way too thin and will deflect. It does not sound as if you have a quality-minded contractor.

Also Know, is cement board stronger than plywood? Cement backerboard is more stable than plywood in high humidity and other wet environments. It won't swell and buckle the way that plywood does, so it's safe to use in mudrooms and bathrooms where things like spills and puddles are normal, as well as in areas with high levels of moisture in the air.

Correspondingly, can you use cement board as a subfloor instead of plywood?

If you're working over a wood subfloor, cement board is the right choice for your tile base. No matter what you're told at a home center, it's not a good idea to install tile directly over plywood, especially in a damp area like a bathroom.

How do you lay cement board on plywood?

Mix a batch thinset mortar, following the manufacturer's directions, using a bucket and margin trowel or putty knife. Spread the mortar onto the subfloor with a 1/4-inch ?notched trowel, starting at the corner of the longest wall in the room. Apply enough mortar for a single cement board sheet at a time.

35 Related Question Answers Found

Should you put cement board under a tub?

Which side of Hardibacker board goes down?

Can you use 1/4 inch cement board on floors?


What happens if Thinset is too thin?

How thick should cement board be under tile floor?

How long does cement board need to dry before tiling?


Do I need to mortar under Hardibacker?

Can you use cement board as a subfloor?

How do you secure cement board to the floor?


How do you install cement board on wood subfloor?

Can I tile on plywood?

Can you walk on cement board?