tiling and ufh in conservatory on chipboard floor - TilersForums.co.uk | Tile Forums

grumps · 17-10-2007

Hi
I am erecting a conservatory on a steel base supplied by a firm called Durabase. It has steel joists and is supplied with 18mm moisture resistant chipboard, which are screwed to the joists, there is 50mm of polystyrene insulation between the joists. I want to fit underfloor heating and tiles. Durabase insist that the floor will be good enough for tiling over but i'm not sure. I'm thinking about binning the chipboard in favour of 18mm exterior ply. I have a few questions,

if i use the chipboard will insulation boards stiffen up the chipboard?

can i use 2 part flexible adhesive with ufh

can i put ufh straight on to the chipboard

if i use ply, would i have to treat the ply with a sealer

I'm thinking about using Varme 200wpm mats, any good?

Many thanks
grumps

**enduro** · 17-10-2007

I would definitely use ply rather than chipbored.

**Dave** · 17-10-2007

hi grumps mate..deffo go for 22mm ply ( rather than 18mm )much better sub-strate than chip board...prime with bal apd neat...or some UFH packs come with there own primer...you could use 2 pack flexi adhesive but if the deflection in the floor is minimal then bal raipd flex will suffice and grout with bal wide joint grout and GT1 admix....good luck and post some pics of before and after tiling............dave..

grumps · 18-10-2007

Thanks for the advice, i'll try with the pics but i'm not much of a computer wiz!
cheers grumps

andy tiler · 18-10-2007

hi grumps chipboard will be fine if there are enough joists to keep it rigid once
screwed down.over board the chipboard with warmup insulation boards a bit
expensive at first but cheaper in the long run.the floor will heat up quicker with these
never use 2part flexi adhesive with underfloor htg because most 2part flexi adhesives are rubberised not recomended with underfloor htg use a single part flexi. u only need a 200wpm if its your sole source of htg
hope this helps

Fred · 18-10-2007

I don't touch conservatories with this blue foam & chip board any more. I used to overlay with 25mm ply screwed every 6 ", with 2 part adhesive. It's just to dangerous re cracks etc.

The same as these floating floors in new builds. The building firms state its ok to tile, and how many times am I called to look at cracked tiles. Even with 2 part, stay away.

**Dave** · 18-10-2007

bal fast flex is fine with ufh...if you use 22m ply as your sub-floor then no need for fast flex bal rapid set flexible will be ok, as for insulation boards you have 50 mm insulation under the subfloor so these are not needed.........dave..

**grumpygrouter** · 19-10-2007

Bit of a close relation to my name that Grumps! Hope people on here don't get confused. LOL.

Grumpy

**Dave** · 19-10-2007

Quote:

Originally Posted by grumpygrouter

Bit of a close relation to my name that Grumps! Hope people on here don't get confused. LOL.

Grumpy

dont think that will happen ..lol lol.

there's only one grumpy git on here............dave..

**grumpygrouter** · 19-10-2007

Quote:

Originally Posted by dhceramics

dont think that will happen ..lol lol.

there's only one grumpy git on here............dave..

Cheers mate!

**Dave** · 19-10-2007

no probs grumps mate...how was your hols.......

**grumpygrouter** · 19-10-2007

Holiday was great, thanks, best one I have had in years. Trouble is, you get over-run with work when you come back so you just want to go away again!

Grumpy