Plywood Under Granite Outdoor Kitchen Countertop

by Cici
(Miami, Fl)

QUESTION:

Can you put plywood under granite counter top for an outdoor kitchen?

ANSWER

Yes you can, but there isn't necessarily a need to so long as the outdoor kitchen cabinets effectively support the granite countertop.

Now, if you are installing granite tile, then yes you will need a surface to lay the tiles on.

If you do use plywood, use marine grade and cover with a waterproof membrane to keep water/moisture away from the plywood otherwise it will rot and warp in time.

Not as big an issue with a granite slab, but with a granite tile outdoor kitchen countertop water is more likely to find it's way to the plywood, so the membrane is important.

Warped Outdoor Kitchen Countertop

by Gina
(Texas)

QUESTION:

I have an outdoor kitchen with 3/4" granite countertops. It is about 7-years old. The "grout" from the seams wasn't installed properly and the plywood underneath the granite are warped and need to be replaced. I have been told that when lifting my granite it may crumble? Is this actually possible?

ANSWER:

Hi Gina, sorry to hear about your outdoor kitchen countertop troubles.

Constant exposure to water or trapped water is not good for any material. While it is possible (given enough time) that the cycle of water seeping through the grout, saturating the granite and then evaporating could degrade your granite it is not likely in 7 years.

Of course, handle the granite with care when removing just to be sure... nothing is ever absolutely certain.

The original outdoor kitchen countertop installation should have used a marine grade plywood with a waterproof membrane on top of the plywood. Thinset and tile on top of that.

This would effectively seal the plywood and keep moisture out so the plywood would not warp and rot.

So, for the repair you certainly want to interview the contractor and get detailed answers regarding exactly how the re-installation will be done and what materials will be used to make the structure as water resistant as possible.

Good Luck,
Ryan

P.S. Get all the facts and simple step-by-step solutions to any problem with our Granite & Marble Maintenance Manuals.

Find the recommended best product brands for cleaning marble, sealing, cleaning granite countertops, quartz and all natural stone.