ᐅ Frustrations with the concrete slab – joints or full-surface pour?

Hello everyone, I have a question about welding the base slab. My screeding contractor wants to apply the welding membrane directly onto the base slab and weld the seams together. A friend of mine says that a bitumen primer should be applied first, followed by full-surface welding. What is the correct procedure?

Whether a primer coat is required depends on the water exposure; a primer coat is almost always necessary. The membrane is either partially or fully welded.

Partial welding is preferred when vapor diffusion is expected, for example from a fresh concrete slab; in this case, a partially welded membrane acts as a vapor pressure equalization layer.

I’m bringing up this topic. This is how we do full-surface welding. But before that, a primer coat is applied. It’s not much work. This way, we’re on the safe side.

Well explained by the mod.