All sceed or concrete first?

[lognak]

Hi
I am having a new door fitted and the same company is raising the porch step to the same level as the corridor (the door has been moved to be flat with the outer wall. Before the porch area was on the outside).
The step is 10cm high, floor space 200cm x 65cm.
The fitter has said he'll put a membrane down and screed it in. I asked if I would need to wait long for it to dry and he said no just a few hours.
It's my understanding you'd have to concrete in the void, slow dry, then screed.

Can anyone confirm? If he just uses mortar/screed would that make the area weaker?

Thanks,
Si

 

[pinenot]

Depends on what screading medium he's using Si, you get some SBR epoxy screeds that will do multiple screed thicknesses.
I remember one contract I did where the owners (C&A) insisted on an SBR that would cure, without shrinkage, on any depth of trench, can't remember it's name though.
Best check with the guy before he starts as you raise a valid point.

 

[AARUSS]

Si

There are a few considerations.
What is the sub base at the moment, 100mm is not much depth for concrete and screed but a bit much for conventional screed. Look at the Mapei website as they do a number of screeds suitable for different situations as the previous poster mentioned, although they can be expensive.

What will be the floor finish as this will determine how critical the drying time is and also the junction between the existing floor and the bit you are going to infill. i.e. if a tiled finish you could end up with cracked tiles at the junction if this is not considered and some kind of expansion joint formed.

Might be difficult not to upset the guy doing the work but you don't want an inferior job that will cause you future problems

 

[noseall]

100mm sand/cement screed is fine.

I have no idea what the above posters are waffling on about regards different types of screed.

It will be good enough to walk on in 24 hours although it will still be green enough to scuff.

It will take several weeks to completely dry out.

You could lessen the screed depth by adding some floor insulation (say 25mm) if you wish, but even this may be a faff for a simple porch.