Chipboard - TilersForums.co.uk | Tile Forums

stoner · 22-05-2008

Hello, hope someone can help me. I have got a job (12m2) of limestone and heating to lay on a chipboard floor. Floor is already tiled with porcelain which i'm going to pull up which has been down a few years with no visible problems. Can i tile straight on top of the chipboard (providing it does'nt pull to bits) or do i really need to put something on top first?

Great site by the way. I have been tiling for 5 years for mainly tile showrooms and just decided to go on my own so heating is a little new to me. Better safe than sorry.

**wetdec** · 22-05-2008

Hi

I would, if it tears up removing the tiles put down 18mm ply, if they come up ok then you need a 12mm ply screwed at 150mm centres as limestone is heavy. Overlay the ply with Durabase CI matting to prevent shrinkage/ expansion cracks from heating later down the road.

If you tell us a little more then we can possibly help further

tiler

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stoner · 22-05-2008

Hi wetdec, picking up the floor too much is an issue. I'm guessing your going to say pull the chipboard up and replace with 18mm wbp. At the moment they have 10mm porcelain down and they don't want to go too high. If i do the above it will only raise by 2 to 5mm plus the heating. Is this the way to go?

**wetdec** · 22-05-2008

Its probbaly your best move unless you want to insulate the floor in which case maybe 2 layers of 6mm would give you a solid base.

Personaly I am a ply person and think weyroc & ply is ok to overheat which would make the previous post ok.

Existing weyroc
12mm ply
3mm Durabase CI mat
heating cable (not mat)

**Around 18mm to here** If you want to drop to 9mm ply then you will need to neat unibond and screw it to the weyroc

What limestone is it m8

tiler

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stoner · 22-05-2008

Hi wetdec, i'm not sure what limestone it is exactly. Can i not use 6mm no more ply glued and screwed or marmox 10mm insulation board?

**wetdec** · 22-05-2008

Yes you can, it will give you the insulation property and a surface to work off but must rest on the state of the floor when the tiles are removed eg are they bowed are there high points. Ply laid and screwed down across existing boards has fewer points of weakness in my opinion and is a solid job.

If substrate boards are the way you want to go then I would hold fire until you can see your chipboard and know what exactly you are dealing with.

tiler

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stoner · 22-05-2008

Cheers for that wetdec. I'm off out for what will probably turn into 1 too many.