I am installing (floating) 3/8" engineered hardwood over a concrete subfloor with 1/8" underlayment. After grinding high spots and filling in larger voids with self-leveler, I have occasional 1/8" or less dips that I have come across while laying the floor. I have read here and elsewhere that roofing shingles can be used on a wood subfloor to raise small valleys.
- Can shingles be used on a concrete subfloor too?
- What are the concerns with using them on concrete if an adhesive like Liquid Nails is used to secure them in place?