Insulation Boards on Weyrock

[Anon1324]

Hi all,

Got my dad's en-suite to tile, planning on laying some electric underfloor heating down and just want verification.

It's a weyrock floor currently. My plan was to lay insulation board (link below) on top of the weyrock, then the UFH with some self levelling compound on top of it, and then floor tiles to finish off.

People I've spoke to have said it needs 3/4" plying before the insulation board - these people aren't tilers so here I am to ask the people in the know.

Do I need ply before my insulation board, or will the insulation board be enough? Surely if I've got to ply it still, the finished floor level is going to be a good 40mm above the carpet in the room adjacent.

Here's the insulation board: Klima Thermal Board Insulation 5 Pack - http://www.screwfix.com/p/klima-thermal-board-insulation-5-pack/93806

Thanks,

 

[Mark Frost]

Those boards from screwfix seem very expensive for pack of 5. I use 6mm marmox boards or Jackoboards. Screw the boards down straight to the chipboard using 25mm screws with tile board washers. Tape and glue the joints of the boards for added strength. Under floor heating on top then leveling compound no need for ply.

 

[Anon1324]

Thanks very informative. So I think I had the right idea by the looks of it. Where do you get yours from?

 

[Mark Frost]

The jackoboard CTD sell them and marmox board Marmox Multiboard - https://www.tilefixdirect.com/product/Marmox-Multiboard-Tile-Backer-Insulation-Boards?gclid=Cj0KEQjwhMjKBRDjxb31j-aesI4BEiQA7ivN-Ehb1AF-1XuCP2ROs5iC-JnYsKvXo07GJ-y0dme1l5EaAliH8P8HAQ#MX6MM-BULK

 

[Flintstone]

Check the floor is stable and not bouncing at all, as chipboard floors often are

 

[Mark Frost]

As @Localtiler says just make sure chipboard is solid. A few extra screws wont hurt

 

[On one]

I would be wary of screwing through the chipboard into the joists unless you can see under the floor

 

[Anon1324]

Floor will be coming up in part for electrical feed and also first fix of new plumbing so should have a good understanding of what's where under there.

 

[Flintstone]

I never ever screw through a floor, unless re fitting a few floor boards or something

 

[Anon1324]

When I put the self-levelling compound down should I just take it all the way to the wall, or so I need to leave a gap between it and the wall (and fixtures such as shower tray). If I need a gap, what's the best way to achieve this?