A foam underlayment on top of the membrane is not mandatory for laminate or Engineered flooring. However, it is recommended as it will soften the walk, keep the floor a bit warmer, and be quieter against footfall noise. Even the thin, cost effective foam at the flooring store will help. A more dense foam will enhance the floor even more. Some laminates already have foam attached so an underlayment is not required.
Non- load bearing walls can be built directly on top of the membrane. This provides airflow under the wall and throughout the entire floor area and elevates the wood framing off the concrete.
Flooring transitions can be done directly on top of the membrane if you plan on changing flooring products from one room to the next.
A plywood subfloor is NOT required. If you do want to add plywood it can be installed directly on Superseal membrane. A 5/8 inch or 3/4 inch tongue and groove is recommended. Glue any joints with a standard construction adhesive. It can be a floating system or you can mechanically fasten it with concrete fasteners or tapcon screws.