Advice needed on newly laid screed please.

adamunited · Apr 19, 2012

Hi all im quickly becoming addicted to this site its fantastic for getting bits of advice and for seeing what other tilers are up to. Im looking for a bit ofprobabl advice really im on a job at the minute a kitcen and bathroom floor both with underfloor heating. the floors have been screeded with a latex levelling by the builder i'd say probably about 20-25mm. he has asked me to tile these floors and ive told him about the need for drying which he is ok about but he has asked if he turns on the ufh to aid drying time will that be ok? i've said i don't think he should and am wondering if i have done the right thing or can this be done? I know about using Bal green screed adhesive but given the price per bag i dont think he fancies that.
Also how long after tiling can the ufh be turned on and why?

Thanks in advance
Adam

Rich · Apr 19, 2012

GRRRRR!!!! Just typed out an essay for a reply and my computer crashed and deleted it!!! It went a little something like this...

Do not turn the UFH on to dry out the SLC, it will not do this, it will just blow the laytex. How long the slc needs to try will depend on the brand used, it should say on the bag but if not then give them a ring and they should be able to tell you straight away. When the slc has had time to dry, tile and grout the floors but thUFHfh needs to stay turned off for a couple of weeks and then turned on at its lowest temp, then increase the temp by no more than 5 degrees per day until it is at its max temp. Then do the same back down then its ready to use. SomUFHfh systems have a built in setting that does all of this for you.

This may seem a bit of a pain and builders dont like it but it is very important to avoid thermal shock, if UFH ufh is turned on to soon then UFH ufh, laytex, adhesive, grout and tiles will be ruined... Not fun.

adamunited · Apr 19, 2012

Cheers rich yes I thought it was a no go doing that. He has had alsorts of problem with the floor in his own house which another tiler did 2 days after it was screeded and turn the ufh on straight away he was shocked when I said u can't do that. Luckily both him and the customer have said if it needs to dry naturally they will wait and have stuck heaters in there now.

Thanks again rich