Do quartz countertops need plywood underneath?

When choosing a quartz countertop, the thickness does matter. This number will determine if you need the additional support of plywood. While a 3 cm quartz can be expensive, it is your best choice in the long run. If you don’t know which thickness to pick, talk to your contractor to get a second opinion.

I am being asked to believe that my new quartz countertop does not need a solid piece of 3/4″ or 5/8″ plywood under all parts of it. The new kitchen cabinets have open tops with only wood strips front and back to support the countertop. Another professional has counseled me to demand the plywood support.

If your quartz is 3/4 thick with somekind of rolled or applied selfedge then we put 5/8 plywood under it. If its the thicker 3cm (1-1/4 thick), no plywood is needed.

What can I use instead of plywood for countertops?

Fabricators put narrow strips of quartz or a polyurethane board as a filler for the countertop to sit flush over frameless cabinets. Polyurethane or quartz remnants are completely waterproof, what makes them superior to plywood for that use.

I would much rather have 1 1/2″ wide 5/8″ thick cabinet grade plywood strip underlayment on 2cm quartz than full 5/8″ roof sheathing. The underlayment is a spacer only; estone needs no structural help over cabinets. If you’re going to cantilever 2cm, use metal square tube.

This is what my research found. the standard thickness for quartz is 1 1/4 inches. Has the 3/4 material already been fabricated? No doubt the standard material is more money, but the plywood adds cost as well. I would recommend Advantech, which uses mostly isocyanate-based adhesives, rather than phenol-formaldehyde used in most CDX, so there is very little smell.

Do I need support under the plywood?

You need some kind of support. You could provide support using rails only at the perimeter and at intervals. However in the US most people provide support under the full surface area using plywood. I do believe so.

How do you support kitchen cabinets under laminate countertops?

However in the US most people provide support under the full surface area using plywood. I do believe so. Either a sheet of plywood laid across the cabinets and the edge of the counters laminated to hide the edge of the plywood or the plywood inset into the tops of the cabinets (if you like the thin counter top look). Thank you, gpraceman.