Sealing screed surface before dry?
Discussion
Firstly, I know that screed doesn’t dry, it cures, but you know what I mean.
Secondly, I know I can’t put my floor down for about 2 months.
My question is to whether or not I can seal the surface to stop dust and sand migration throughout the rest of the house by putting a surface sealant down or something? But which will allow for moisture to be released.
Anything? It’s been walkable for 2 days now so we’ve only got about 58 days left until I can get a floor down and stop being annoyed
Secondly, I know I can’t put my floor down for about 2 months.
My question is to whether or not I can seal the surface to stop dust and sand migration throughout the rest of the house by putting a surface sealant down or something? But which will allow for moisture to be released.
Anything? It’s been walkable for 2 days now so we’ve only got about 58 days left until I can get a floor down and stop being annoyed
dsl2 said:
If its anhydride pumped screed you absolutely need to sand the surface to remove latency if not it will still be ringing wet in 2 mths time, so I'd say no you can't seal the top of it as you need to get the moisture out of it not impede its release.
I suppose that you could seal it with something breathable like whitewash but it would of course slow the drying. Depends whether dust reduction or time reduction is important to you. From a strength pov it's best to keep it wet but that's not usually the primary concern.Screed both cures and dries.
What is the finished floor surface going to be?
If it's tile you can use BAL green screed now if you want. Alternatively you can use a decoupling mat.
If it's not tile and you just want to keep the dust down a coat of diluted PVA will help. If you are planning to tile don't use PVA.
What is the finished floor surface going to be?
If it's tile you can use BAL green screed now if you want. Alternatively you can use a decoupling mat.
If it's not tile and you just want to keep the dust down a coat of diluted PVA will help. If you are planning to tile don't use PVA.
It's a standard sand/cement screed that was barrowed around to the extension before being laid relatively flat by the builder.
We're putting laminate down as it matches what's in the kitchen (if we can match it!) and it's very plasticky on the rear surface but obviously it's basically cardboard mixed with papier mache in between the top and base surfaces.
We'll be using a decent underlay - originally used a sort of polystyrene type one which was an integral dpm due to the unknown nature of the slab in the rest of the house but I think it's crap so won't be using that again - I'll go with a compressed cardboard type one I expect, but obviously want no damp in there before I put it down.
Would diluted PVA help at all? It's gritty/sandy and possibly slightly too large to stop movement - I don't really know what I was expecting as a solution to be honest, other than patience!
We're putting laminate down as it matches what's in the kitchen (if we can match it!) and it's very plasticky on the rear surface but obviously it's basically cardboard mixed with papier mache in between the top and base surfaces.
We'll be using a decent underlay - originally used a sort of polystyrene type one which was an integral dpm due to the unknown nature of the slab in the rest of the house but I think it's crap so won't be using that again - I'll go with a compressed cardboard type one I expect, but obviously want no damp in there before I put it down.
Would diluted PVA help at all? It's gritty/sandy and possibly slightly too large to stop movement - I don't really know what I was expecting as a solution to be honest, other than patience!
Drying time depends on a number of factors and you can't assume '2 months' as a fixed rule in every case
To be certain you really need to find out from the flooring manufacturer what moisture content the product will tolerate. Any good flooring contractor will take specific readings from the screed usually by placing a hygrometer on the floor and leaving it for at least 24 hrs
If it's not within tolerance, and you need to get the floor laid, there are a number of paint on surface DPM products which you can use in order to lay the flooring early. They work out around £10/m2
To be certain you really need to find out from the flooring manufacturer what moisture content the product will tolerate. Any good flooring contractor will take specific readings from the screed usually by placing a hygrometer on the floor and leaving it for at least 24 hrs
If it's not within tolerance, and you need to get the floor laid, there are a number of paint on surface DPM products which you can use in order to lay the flooring early. They work out around £10/m2
..not normally, usually manufacturer's technical dept.
If you are fitting yourself, you may be able to get a local flooring firm to come out and do the test, otherwise to be safe I would use a surface DPM, such as:
https://www.tremco-europe.com/en_GB/products/produ...
If you are fitting yourself, you may be able to get a local flooring firm to come out and do the test, otherwise to be safe I would use a surface DPM, such as:
https://www.tremco-europe.com/en_GB/products/produ...
Too late for the OP now I laid my sand and cement screed 9 days ago. Mix was 3/1 with a quarter litre of Ronascreed additive per mix
Even though we cocked up with the floor levels and had to lay it 125mm thick
it is now ready to tile on - 75% moisture content measured.
Cracking finish as well no “dusting” even if you scuff your feet.
Even though we cocked up with the floor levels and had to lay it 125mm thick
it is now ready to tile on - 75% moisture content measured.Cracking finish as well no “dusting” even if you scuff your feet.
Edited by dickymint on Tuesday 21st November 17:46
Ha, I wish i’d Known that!
Not to worry, dehumidifier is running full time to stope condensation on the windows and doors, taking about 3 litres a day from the room but that will include the kitchen and dining room it joins.
Will give the cardboard trick a go in a few weeks and see how it is - although I know a floor guy who will probably have a moisture measured to be a bit more precise.
I’m getting in the habit of brushing my feet off just as I leave from one room to the next so will probably get over it soon enough.
Not to worry, dehumidifier is running full time to stope condensation on the windows and doors, taking about 3 litres a day from the room but that will include the kitchen and dining room it joins.
Will give the cardboard trick a go in a few weeks and see how it is - although I know a floor guy who will probably have a moisture measured to be a bit more precise.
I’m getting in the habit of brushing my feet off just as I leave from one room to the next so will probably get over it soon enough.
OP, I’m no expert but be careful force drying with a dehumidifier like that.
Any screed I’ve ever seen the longer to dry the better - even to the extent of actually damping it down with a fine hose spray and covering with plastic to keep it damp for longer!
I’d have thought the better way would be to use products designed to decrease drying time rather than force drying?
But as I’ve said, I’m really only guessing.
Any screed I’ve ever seen the longer to dry the better - even to the extent of actually damping it down with a fine hose spray and covering with plastic to keep it damp for longer!
I’d have thought the better way would be to use products designed to decrease drying time rather than force drying?
But as I’ve said, I’m really only guessing.
Rosscow said:
OP, I’m no expert but be careful force drying with a dehumidifier like that.
Any screed I’ve ever seen the longer to dry the better - even to the extent of actually damping it down with a fine hose spray and covering with plastic to keep it damp for longer!
I’d have thought the better way would be to use products designed to decrease drying time rather than force drying?
But as I’ve said, I’m really only guessing.
Good guess. As above, what you've said will achieve maximum strength. If you only ahieve half strength then that's OK in the majority of cases. If you force dry it and only ahieve one third strength it may be OK, dpends on the mix and end use.Any screed I’ve ever seen the longer to dry the better - even to the extent of actually damping it down with a fine hose spray and covering with plastic to keep it damp for longer!
I’d have thought the better way would be to use products designed to decrease drying time rather than force drying?
But as I’ve said, I’m really only guessing.
Ok, i’ll Maybe run it a little less than I’ve been doing then.
I’m amazed it pulls moisture out of the screed though as its inlet is about 2 feet off the ground and it seems to use circulating air to get air passing through it.
Out of interest, just how strong does the screed need to be to support a dining room table and some laminate flooring?
Might just keep the thing running during the night to stop the condensation and let it air naturally in the day time.
I’m amazed it pulls moisture out of the screed though as its inlet is about 2 feet off the ground and it seems to use circulating air to get air passing through it.
Out of interest, just how strong does the screed need to be to support a dining room table and some laminate flooring?
Might just keep the thing running during the night to stop the condensation and let it air naturally in the day time.
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