UFH on concrete floor - advice on screed etc please

[lady]

Hi!
This is a great forum, have been reading this a while. Could someone point me to right direction - I am putting down UFH in kitchen, small loo and utility room app. 15m2 altogether. Have removed the horrible plastic tiles and ALL of the HORRIBLE black stuff and now have just the concrete base but this is not even. The differences are max 3mm. Now the question: Do I need to prime or screed the floor before putting to UFH mat and self levelling compound? If yes, could I use the self levelling compound which I have extra or do I need to buy yet another product :smilewinkgrin: ?

 

[Time's Ran Out]

If you are only talking 3mm then this will be taken out with the levelling compound when you fix the mat.
Have you considered an insulation membrane first to make the UFH mat more cost effective. I'd certainly use a primer in accordance with the levelling compound manufactures information. The SLC should be a fibre enhanced type for the heating mat which could be up to 200w per metre output. What you should be aware of is none of the heat mat companies that I use recommend taking a single mat across doorways and you may have to consider 3 separate units. (For installation you must have the final connection by a Part P registered Electrician.)

 

[lady]

Thank you John. Really useful advice. I will use primer - hadn't thought about that but makes sense. The SLC is says to use Palace Tilers Primer and I rang a tile shop where bought the SLC, they advised to use acrylic primer (they don't sell PTP) so don't now know what to buy now. Will any acrylic primer do? Any recommendations? Interesting about the recommendation not to take a single mat across different rooms, I wonder if that is because the risk that people will screw down thresholds etc. I am tiling all rooms with same tiles and won't put down thresholds so can't see this being a problem. The SLC only says suitable to most types of UFH. Hope that is fine..