Kitchen subflooring for ceramic tile.

Old 12-24-19, 04:36 PM
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Kitchen subflooring for ceramic tile.

My house was built in 1927 and I'm getting ready to tile the kitchen and bath. Kitchen first. The floor now is original typical tongue and groove pine over tongue and groove sub flooring run at a 45 degree angle to the joists. The floor is rock solid with no give all. Over the years there have been a lot of patching from previous damage of some sort. Anyway, I plan on removing the upper finish flooring and replacing it with a plywood. How thick should I get? And also there's a layer of roofing tar papper between the sub floor and finish floor layers. I suppose it's vapor barrier... Is that goi g to cause me any problems? Thanks.
Old 12-24-19, 04:55 PM
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The tar paper wont cause problems but typically you want to go over your subflooring and look for squeeks... set nails (they often work their way partly up) and screw down any areas that squeak, pulling out the offending nails. You cant do that if the tar paper is still there. So you might want to remove it for that reason.

Whether or not you replace it is up to you. But I would go back with a minimum of 1/2" ply. You don't screw it to the joists and you dont glue it. You just screw it to the existing subfloor. Then you are ready for Ditra or 1/4" cement board.

All of this assumes your existing joists are not undersized or overspanned. If they are, your tile will eventually fail.

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