The screed I'm soon to tile on has been repaired using sand and cement mix where pipework has been altered, and is a bit crumbly.

Would it be best to prime with SBR prior to fixing tiles?

Thanks

Where it is crumbly I would brush out any loose screed, Prime and use some spf to fill in any voids

I'd remove crumbly mortar and repair with a flexible substrate cc, how deep are pipes?

The pipes are close to the surface, ie almost level in places.

Whitebeam, what is spf???

Doug, what do you mean by a flexible substrate? Are you talking about fast flex tile adhesive, or something else.

I'm using fast flex tile adhesive

Originally Posted by cornish_crofter

The pipes are close to the surface, ie almost level in places.

Whitebeam, what is spf???

Doug, what do you mean by a flexible substrate? Are you talking about fast flex tile adhesive, or something else.

I'm using fast flex tile adhesive

SPF - Single Part Flexible, Hugo mate.

Originally Posted by cornish_crofter

The pipes are close to the surface, ie almost level in places.

Whitebeam, what is spf???

Doug, what do you mean by a flexible substrate? Are you talking about fast flex tile adhesive, or something else.

I'm using fast flex tile adhesive

Whitebeam and me are on about the same stuff single part flexible (spf) adhesive, looks like you're sorted mate

The penny has now dropped!

Thanks