Could that plywood be temporary? Is it possible that contractor is using plywood to add more visual thickness to the countertop?

Page 40 please.

Thank you. The plywood is permanent. The counter will go on to it. I will check out the manual. Thank you.

I am a fabricator. 10" overhang is no problem. The plywood underlayment is unnecessary.

We were asked to put 3/4 plywood on top of cabinets extending to overhang by the quartz fabricaters we used and they did a great job. Overhang seems very strong without any extra support other than ir OSB board underneath.

I think some of this is regional. In CA most slabs sold are 2 cm and most installers will place a layer of plywood under all the granite, quartzite or quartz.

The plywood was not leveled and hence the gaps. The contractor re did the plywood and it's leveled now . Thanks!