UFH cant be turned on for a while !

[dagger]

Whitebeam - That schluter stuff looks great but cant see her forking out for 200 m2 - Looks like she will have to get the UFH on - or wait for the 7mm per week = 10 weeks :incazzato:

P.S. could she put the UFH on after 3 weeks of natural curing for a few days and then tile ?

200m of Schulter, 30m rolls = 210m = 7 rolls... £1050......or wait?
but if the tiles are stone......best investment ever!

 

[White Room]

You could be looking at some serious problems if she dos'nt, there a lot of moisture to be released from the screed.

It's her choice, give her the facts and get it in writing

 

[Ajax123]

Natural drying time for sand cement screed and hand floated concrete is accepted generally as 1mm per day. They should be cured for 7 days following installation to promote strength gain so drying commences 7 days following installation. 75mm (3") is trherefore7 days curing time and 75 days plus natural drying time. Embedded underfloor heating systems should be comissioned prior to the appliaction of floor coverings and this should not be carried out on sand cement for at least 28 days. Bear in mind that drying times are usually based on atmospheric conditions of 20 degrees centigrade and 60% relative humidity with ventillation.

If it is one of the many polymer modified sand cement screeds they are supposed to dry at 25mm per week but this is usually based on 50% Relative Humidity and 20 degrees C so conditions which are almost impossible to acheive in the UK.

This time of year we have high humidity and low temperature so the drying time needs to be adjusted accordingly. You would be best to measure the moisture content before tiling. Otherwise you could come unstuck (Excuse the pun)..

To comission the underfloor heating you would normally turn the flow temp on at ambient so this time of year say 15 degrees C and leave it there for at least 3 days. INcrease by an absolute maximum of 5 degrees per day up to its maximum temperature and then reduce it down to its operating temperature for as long as you like to dry the screed and then switch it off 48 to 72 hours before moisture testing and tiling. Make sure any cracks that appear are repaired prior to tilingas well.

If you don't comission the underfloor heating first then your tiles will delaminate.

The rules for anhydrite are slightly different.

 

[Dan]

Just bumping some threads in the underfloor heating forum. You can now find and search for both electric underfloor heating and water underfloor heating threads. By the way, if you feel some of the threads you want to be seen at the top of the forum need to be bumped back, for the next month or so from now, feel free to do that. Although it's not usually something we allow, whilst we're going through this process of changing over forum software, we see the need for this to happen.