Dry screed

[DIYgonewrong]

I have just made a dry mix of screed (1part cement - 4part sharp sand)
I have not added any water and have now laid it dry! I have since realised that the mix is never going to harden Can I spray water on it to make it go hard or is it best to dig it up and start again with a damp mix? The patch I did was only a very small area in a fire place hearth about 800mm x 400mm x 40mm

Any advice would be great as I am feeling rather disappointed in my self.

Thanks in advance

 

[Deluks]

When you say 'just' do you mean today? It'll still be powdery so scoop it up and start again.

http://tinyurl.com/screeding

 

[alittlerespect]

Dry mix does not mean 'dry' in the literal sense, it needs to be moist, to gauge the mix add a small amount of water at a time and test the mix by picking up a handful and rolling it into a ball - when it stays together you have the right mix. Once you have done this a couple of times it should become second nature and you should be able to tell the correct mix by its colour rather than consistency.

Best bet is to take up and bag what you have laid, and remix and start laying the screed from scratch.

Good Luck

 

[ColJack]

I did th same thing.. mixed a bucket full "dry" and tested it for the "clump" factor to guage how much water I'd need to add.. turns out none.. the sand was damp enough already..

unless you got kiln dried sand then odds are it's quite damp to start with.. grab a handfull if you've any left and see if it holds shape when squeezed in the hand.. kind of like sand castles..

 

[DIYgonewrong]

I did th same thing.. mixed a bucket full "dry" and tested it for the "clump" factor to guage how much water I'd need to add.. turns out none.. the sand was damp enough already..

unless you got kiln dried sand then odds are it's quite damp to start with.. grab a handfull if you've any left and see if it holds shape when squeezed in the hand.. kind of like sand castles..

Thanks guys for your speedy reply.

ColJack, I use bag of wickes sharp sand and it looked quite dry but as I mixed the cement in and did the 'clump' test it held its shape so thought this would do the job as is.

I took the advice and scooped it all up and mixed in a bit of water, turns out a bit too much but all is good i fear not. It is a very small patch and we intend to carpet over the top so as long as it is level I hope I will be ok!

Cheers

 

[Deluks]

Give it a few weeks to dry out, put some concrete floor sealer on it if it turns out dusty.

 

[neds]

I had some mixed results with my first screeding. Its all too easy to add too much water because you think its easier to work with, but that's not screed. Key thing is getting it level and floating it off.

 

[gregers]

are you mixing by hand or cement mixer,if cement mixer the easiest way to tell if its just enough is when it goes into little balls.

 

[alittlerespect]

Hi!

The mix should have been ok if the material held together! Did you break the 'clump' to see if it fell into small clumps rather than disintergrate back into powder?
As you have found out, its all to easy to make the mix too dry and to add too much water, so put the whole experience down to lessons learnt!

If you have any problems with the completed floor being a bit bumpy, pick up a bag of latex floor leveling compound to finish off the floor.

Regards

 

[DIYgonewrong]

Yes I am mixing by hand and its all done now thanks. Just looks a bit like a concrete floor because of all the water in it!

I will be using a laytex self leveler to get a nice finish as the whole floor is out of level.