Plywood foundation for granite slab counter top

[brian.forsman]

I'm replacing the counter tops in my kitchen with granite slab. I'll be removing the old counter tops myself, and installing the plywood foundation over the existing cabinets.

Are there any issues with driving in fasteners from above the plywood rather than below?

Most everything that I've read calls out fastening from below. For most of the job I will be able to do this. However I have a raised bar area (4" wide x 72" long) that is drywalled on both sides, so I won't have access from beneath.

Thanks, Brian

[dadiOH]

Only the fact that you can't get it off without removing whatever is on top.

[Robert Allison]

In addition to that, you should not use plywood over the boxes. Just strip the top with 1x2 and screw it down or use nails and glue. This configuration will give adequate support and allow access underneath for shimming where necessary (and it will be necessary). If you install the plywood, it makes the installation of the granite MUCH more difficult and does not add to the strength of the finished product.

[Malcolm Hoar]

Ummm, let's assume for a moment that he fastens the ply from below and then installs the granite. I guess he can subsequently remove the fasteners without removing the granite. Fine! But, pray tell, how's he gonna remove the plywood without removing the granite? Slide it out? With a 1000 pounds of granite on top? ROTFL.

[mike]

I think the advantage he's referring to is not having to unbond the granite from the plywood upon removal. It can be removed all together.

I agree with the other response about not using plywood. It'll just get in the way of shimming.

[Malcolm Hoar]

True although that's not something he should need to do very often ;-)

Yes, I agree with that too. In fact, I'd let the granite contractor handle the sub base too to avoid any disputes later. At least, that's how I handled it.

I was prepared to do the demolition of the old countertop myself to save some bucks. However, in the end, my granite contractor did that for a price I couldn't refuse.

Some contractors wanted $1500 for demolition and haul away but I paid one tenth of that (a no brainer). It took 4 guys a full half day ;-)

[Oren]

Not a granite person. In our area the granite installers are placing the material over 1/2" particle board and screwed from the top.

Shim/level and sink the screws from the top. They state they can level the granite with 1/8" or smaller shims only - no more than 1/8".

I've seen this in four owner built homes the past year or so.

Ask the granite person what he wants.

[John McGaw]

I'd just forget about everything I've read and determine what your granite installer wants. They are the ones who need to get everything installed and working right and they probably don't want the stone cracking any more than you do.

[EXT]

Counter tops get replaced. Even granite can become damaged if chipped or cracked because of a number of reasons. Bonding direct to the cabinets can make removal difficult without further damage to the cabinets. Personally, and our installer had no problems with it, a 3/4" plywood base was installed over the cabinets. It was all attached with screws from below so that it could be removed without having to pry the granite off the top to locate the screws. It is more work to install the plywood this way but I find it better. If you have a drywalled section, you could cut an access hole in the drywall as it is easily patched.

[Oren]

Sorry I have to ask. How often will a home owner need to remove a granite counter top?

-- Oren

"equal opportunity, not equal results"

[Malcolm Hoar]

A home owner cannot remove a granite counter top. It takes a home owner plus several (large) buddies! Answer: not very often!

My countertop used to comprise of tile over ply. The ply was fastened from above. When the tile was demolished to make way for new granite slab, the top-side fasteners didn't present any problems at all. In fact, the granite was installed over the old ply (except for the sink area where a new cutout was required).

Frankly, I think there are much more important issues to fret over when installing a new countertop than orientation of the ply fasteners.

[Oren]

If I can orientate a level, the granite guy will be happy.

Put the fasteners where essential, but that's just me :)

Plus, comments from the granite guy.....are appreciated.

:))