More newbie questions [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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Mr Fixit eh
10-13-2004, 01:24 PM
Great forum, I'm impressed.

I've searched and read previous threads on these topics, and I have a few more newbie questions..........

I'm planning on installing 6 inch tile for a backsplash. Does it require cement board backerboard, or can it be installed directly on painted drywall?

The countertop will be 3/4" pressure-treated plywood with 1/2" cement board installed with thinset between the plywood and the cement board. I'm not clear about the spacing of the durock screws. Is that 8" o.c. in both directions? That seems like a very high density of screws.

I'm planning on using epoxy grout for the countertop, but the dealer recommended against using epoxy grout on the backsplash because it is difficult to work with. Will the difference between epoxy grout and regular grout be unsightly?

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10-13-2004, 01:48 PM
From USG's durock installation guide:

"Fasten to the plywood with
1-1/4 DUROCK Brand Wood
Screws or 1-1/2 hot-dipped
galvanized roofing nails, spaced
8 o.c. in both directions and
around edges."

Don't argue with the manufacturer, especially if you want them to honor their warrenty. :D Some would suggest a closer spacing near the edges. ;)

Tile may be applied on drywall in "dry" areas. Backsplashes are dry areas. Clean the pain of any grease and use a medium grit sand paper to scuff any glossy paint.

I don't think pressure treated plywood is what you want for your countertop. Instead, use AC or BC exterior rated plywood. You can waterproof the countertop with a paint-on waterproofing membrane, such as Redgard, before you set the tile.

I dunno about the visual difference between epoxy and regular modified grout.

Mr Fixit eh
10-14-2004, 07:32 AM
To apply the backsplash tile to painted drywall, would you you use mastic or thinset?

I already have the pressure treated plywood cut and installed. Will it cause any serious problems? :cry:

Many thanks

10-14-2004, 07:49 AM
Welcome, Mr. How about a first name? :)

You can use either thinset or mastic to set the backsplash tiles. We generally recommend thinset for everything; only one product to buy and you don't hafta remember where you can use it and where you can't. Besides, we just don't like the stuff. :D

The PT plywood, like it's cousin, PT dimensional lumber, has a very, very high moisture content and will shrink as it dries. The plywood is much more dimensionally stable, of course, but it's still gonna shrink. Was it old, or right off the shelf inna big-box store? Were you able to carry a full sheet of 3/4 inch by your ownself? Are you a large person? We're trying to determine the water content, here. ;)

My opinion; worth price charged.

Mr Fixit eh
10-14-2004, 10:13 AM
I had the PT ply cut at Home Depot. Sounds like I should let it sit for a bit to reduce the water content?


10-14-2004, 10:32 AM
Are we talking about a couple of sheets of plywood? 'Cause, you could be waiting until spring for the PT stuff to dry out.

Sometimes, it takes a back step to go forward.

Mr Fixit eh
10-14-2004, 02:02 PM
Two sheets of plywood ripped into 2' x 8' pieces to provide approx. 32 sq. ft of countertop.

What will happen if I go ahead with the PT plywood, cracking? Loose tiles?

John Bridge
10-14-2004, 05:04 PM
Hi Steve. Welcome aboard, eh? :)

The question is how dry or wet is the plywood now? It could take a couple months to get it down to an acceptable moisture level.

10-14-2004, 05:25 PM
From Homer it was prolly pretty fresh; couple months is optimistic.

Take that stuff back to ol' Homer, Steve. He aughta give you most of a refund since he sells half sheets of that sorta thing anyway. Be fair, though, don't try to charge him extra for the cuts. :D

I really would do that. Building that counter top is a bit of work and it would be a shame to do all that and end up with problems because of wet plywood. Are we sure you'll have problems if you use it? No, we're not. But the smart money isn't gonna bet with you on this one.

My opinion; worth price charged.