Floor screeds gone powdery

[yar1950]

On wednesday I had three rooms screeded, thickness about 80mm. It was laid on a hot day. I checked it out today only two days I know but it's like powder. I can almost scrape it up with my finger nails. I know screed it supposed to take months to set but if it has turned to dust in two days surely it can only get dryer and more powdery with age?
I was a bricklayer years ago and it looks remanisant of too strong a mortar mix used in too hot weather. Any thoughts on this greatly appreciated.
Forgot to mention it's on 75mm kingspan.

 

[roughcaster]

Hi,
You say your floor screeds have gone powdery only 2 days after being laid and you think it might be due to being to strong a mix.Sounds to me like it was to weak a mix that maybe dried out too fast.If you can scrape and powder it with your finger nails, that is not a good sign. I have laid floor screeds as a semi dry mix in warm weather and can honestly say I have not had this problem.You say the screed was laid on 75mm Kingspan.I dont know what effect that would have if any.Cement /plaster,anything drying out too fast is not good.Even if you had gently sprayed the floors 2 or 3 times a day,just to help it cure more slowly,that might have helped,you could try doing that now ,but it is probably to late.Still think that the mix sounds to sandy and dried too quick.
Regards:Roughcaster.

 

[yar1950]

Hi roughcaster, thanks for you help. it is very informative. I will get the govenor back to see what he says, if I'm not reassured with what he says, I will pay for a independant surveyor.

Thanks again

Ray

 

[roughcaster]

Hi Yar1950,
Please keep us updated on your floor screeds,it would be nice to know the outcome.Hope all ends well.

Regards:Roughcaster

 

[yar1950]

Will do Roughcaster

Ray

 

[yar1950]

Hi roughcaster, I sprayed the screed after your reply and also opened all the windows as with all these new building regs the house is air tight and can't breath. The screed did seem to recover a bit but was powdery in patches. They poured some of that floor leverler stuff to seal it.
For some reason they did the sreed 95mm instead of 75 so I wondered if this had any bearing on the drying.
The problem with making it so high is the worry of the building inspector complaining that the bottom stair rise is now half inch less than all the others, as you know they require them all uniform, still we will see on completion.

Thanks again foryour help.

Ray

 

[roughcaster]

Hi Yar1950,
Thanks for the update.Well at least they came back to look at your job.You would think that the thicker the screed,the longer it would take to dry,but there you go.It is always good to keep cement/concrete what you call "Green" for as long as possible with a fine spray,or covering over with wet hessian or polythene to keep the moisture in and prolong the cure.Good luck with you job Ray,and we will talk again.

Regards:Roughcaster.