Screeding - how to deal with depth decreasing

[emmamason]

Folks,

I need to screed an area of floor (about 2m x 1m). At the moment the floor slopes, so the depth of screed at one end would be about 50mm, but it would peter out to nothing at the other end.

I know that the screed should have a minimum thickness, so how do I deal with this problem? Should I use a floor levelling compound instead? I will be laying a solid wood laminate on top when I'm finished.

Thanks,
Emma

 

[Burnerman]

Personally I think that 50mm is a wee bit thick for self levelling compound alone, so I'd consider reducing this thickness a bit with a cement screed first, and after this has set, finish off with the self levelling compound.
John

 

[Blagard]

Well I hope the entrance to this area is at the shallow end!

That is a nasty fall and if the floor was already a screed I would even consider lifting it and doing it again. But what existing floor are you contemplating putting the screed onto?

You can get floor levelling compounds for dealing with thicker applications but even then you would probably have to do it in layers. - In my experience these are special order compounds, as most floor levelling compunds from a builders merchant are only suitable for single thin coat applications to deal with nominal variations.

Another solution is to fit a new floor over the old using ply on firing strips to level it up. This will raise the high end by the thickness of the ply before you put on any laminate!

 

[emmamason]

The existing floor is concrete and is a bit of a mess. I knocked down a partition wall and the floor on one side of the wall was slightly lower. It's difficult to describe but this lower section is the bit with the slope which I want to level out and bring up to the same level as the rest of the floor. I measured it properly last night and it slopes from 40mm to 0mm over 2m.

I didn't think about laying the levelling compound in layers - think I might give that a try!

Thanks for your help.
Emma

 

[Blagard]

I didn't think about laying the levelling compound in layers - think I might give that a try!Emma

Incidentally this was a technique used on one the contracts I worked on - a major refurbishment of offices where some of the old existing concrete floors needed to be levelled prior to new carpet tiles (Urgh!). I don't know the name of the product but I had to keep an eye on the works on behalf of the client to agree the amount of compound used. I don't recall what the time span was between layers so I suggest you try emailing the manufacturer to find out beforehand.

There are actually some high performance screeds that would do your job, but they are specialised, expensive and not a DIY job.

 

[Chukka63]

for a small area you're talking about i think i would rip out the existing screed and relay,but you must insure there is a DPM.you could paint with RIW or similar to be on the safe side/

 

[alittlerespect]

Hi

Use a sharp sand and cement mix - say 3 parts sharp sand to 1 part cement - mix up a small quantity as a slurry and apply by stiff brush to the affected area - allow to go 'green' and then lay a dry mix of the above - same ratio - finish with a wooden float then when dry (and if necessary - finish off with a laytex self leveling compound).

Note: Dry does not literally mean dry - add enough water so that when you form a ball of the mixture in your hands it stays together and does not fall apart or crumble.

Regards