Asked by: Saturnino Scheurlenasked in category: General Last Updated: 27th May, 2020
Do you need plywood under cement board?
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.