Customer wants to remove a formica counter ( 1.5″ thick plus formica) and replace with a slate tile about 3/8″ thick. Wants to reduce the thickness of the existing counter so new tile will fit under existing wall tiles and cabinets. Part of the current counter is 25″ wide and is supported by cabinets ( this area makes a breafast bar). The overhang on each side is about 10 “. In order to keep everthing at the same level the supporting substrate will be reduced to only 1”.
Question: Would unsupported 1″ thick substrate be enough to support the new tiles and not have the grout lines open when weight is placed on it : ie like your elbows after a meal or typical stuff you put on a kithcen counter.
What is the strongest substrate: plywood, part board, MDF OR cement board
Replies
I think I would use tile backer board like Hardibacker. It is 1/2" thick so a double layer should be just right. Once the backer is in place, you can lean on it and see if it seems to deflect. If there is a question, you may be able to add some decorative brackets to help support the overhang. I think it will be strong enough as long as you are solidly fastened to the cabinets. You may have to put some cross members in the top of the cabinets for a firm connection. Plywood and particleboard can curl up when the thinset is applied.
Beat it to fit / Paint it to match
I just don't understand why every one is so set on hardi and cbu ALWAYS!
Either one adds weight not structural strength which is what you should be looking for here.
Double 1/2 in plwood is gonna be twice as strong as a single layer of ply with cbu over it. That still may not suffice.
I have never seen plywood curl or otherwise when setting tile or stone with thinset.
You should not let your client dictate your methods.
EricI Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
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If you troweled thinset onto a loose piece of plywood it might crown a bit >; )
Perhaps 3/4" A/C plywood plus 1/4" cementboard (better support than just cementboard) or why not go thicker and butt the slate to the tile nice and tight and caulk it in with a thin bead of clear silicone?