I am building a small guest house outbuilding.
I have a concrete slab with the 4 inch PVC pipe coming up from the exterior edge of the slab. Then it connects to a street 90. I tried to set it up to be at the proper final finished floor level height with tiles installed later on...I wrapped it with cardboard to allow the flange to slip down over the street 90. I test fit and it seemed OK.
But after the pour, the flange is not seating fully flat down on to the concrete slab.
Maybe the lower portion of the cardboard kind of crushed in and the space for the flange does not go down as low as I had planned. Maybe a quarter inch gap.
What should I do? Can I put a spacer in there and drill down through into the slab and screw down the flange with stainless steel screws?
Should I trim down the flange pipe length at its bottom end to allow the flange to seat on the slab?
Also do I use a masonry bit and pre-drill pilot holes and then epoxy in the screws?