Laying Underfloor heating boards

[wobbilyhead]

Hi,

Hope this is the right forum!

This weekend I'm going to be laying the Insulation boards for electric mat underfloor heating and then the mat itself before a tiler comes in and lays the floor on monday/tuesday. I'm happy with the electrical side of it but not sure how to lay the insulation, i've assumed it's with flexible cement based adhesive but I'm not sure on the finer points such as:

What sized trowel I need?
Do I lay them the same as a tile on a thick continuous bed of adhesive or will a thin layer just to stick them suffice (floor is pretty level and new)?
Was I right with flexible cement based adhesive?
Do I tape all the edges with a suitable tape like duck tape?

Thanks for all your help

 

[lancenotalot]

What boards are you using?
I use a 10mm sq notch then once they are all in place I screw down every 200mm.

Make sure the adhesive is flexible.

 

[bathstyle]

Yes, I agree 10mm is fine, if it's going onto concrete then a thicker bed is more advisable so you can bed it down well as it isn't normally screwed

 

[wobbilyhead]

He boards are 10mm thick foam type for laying onto a concrete floor.
I've got a 6mm would it be much difference or is it worth getting a 10mm.

 

[bathstyle]

Depends on your floor, is it very smooth??

6mm is probably more suited to timber as it is screwed down, I think 10mm is better that way you can really bed it down to achieve a solid bed of adhesive

 

[wobbilyhead]

It's a new screeded floor so as smooth as that usually is.

 

[bathstyle]

I would go for 10mm

 

[lancenotalot]

http://www.screwfix.com/search.do;j...PCFFA?_dyncharset=UTF-8&fh_search=10mm+trowel

For the sake of £7 I would get one.

 

[wobbilyhead]

Thanks, will do