underlayment question [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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gus steeler
02-19-2010, 06:45 PM
Hi all,gus here,new to the site,great site you have hear! I just have a couple of questions i need some help on,i am planning on tiling my kitchen and dining area,currently the dining area has carpet,and the kitchen has vinyl peel and stick(we just moved in) anyhow,when i removed the peel and stick tiles i discovered a plywood underlayment under it,i believe its a quarter inch,so,upon pulling my carpet back i realized i am going to have to add a quarter inch in order to level the two areas, when i was at home depot they directed me to some underlayment boards that had all x's marked for where to nail them down,if someone is familiar with these,are they any better then if i used 1/4 one good side plywood? plywood is cheaper,and bigger sheets,any help would be great,and what would be better,ringed nails,or deck screws?

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Brian in San Diego
02-19-2010, 07:21 PM

Welcome to the John Bridge Forums. First of all, the 1/4" plywood has to be removed. No plywood less than 3/8" in thickness can be used in a tile installation. I'm assuming you are on a raised foundation. If so, the next thing you need to determine is whether your joist structure will support a tile installation. Use the Deflecto in the dark blue toolbar above to help determine that for you.

There's a ton more you may need to look into before starting this project. I would also beware the man or woman who wears an orange or blue apron and gives free advice. The advice could end up costing you...big time.


02-19-2010, 07:27 PM
Hi Gus, welcome to the forum!

The plywood in your kitchen is probably not (almost absolutely) installed correctly for a tile installment. Even if it were you would still need to use a suitable underlayment for your tile substrate.

While tile can be installed directly to plywood it requires a very specific process - and I do mean very specific.

You need to check your joists to ensure you have proper deflection for a tile installation. If you do you should probably tear that kitchen floor out and add another layer of regular plywood over the entire floor, then a suitable tile substrate, then tile.

02-19-2010, 07:28 PM
Hi Gus, welcome,

Brian is absolutely right. You need to take that 1/4" ply to the curb for starters. Go ahead and consult the Deflecto, then let us know what you've got.


02-19-2010, 07:28 PM
And what Brian said . . . :D

gus steeler
02-20-2010, 09:13 AM
thanks everyone for your prompt replies,i will check my structure and the deflecto,i am leary about the orange and blue,i will be back on in a bit,thanks again. Gus