Help Me Unknown Substrate - TilersForums.co.uk | Tile Forums

cjbombero · 03-07-2008

Went to quote for re-tiling an en-suite yesterday, everything was pretty straight forward except for the substrate. The wall appears to be skimmed plaster with a fiberous wood board underneath, it alsmost resembles wood chippings! The customer hasn't bought any tiles yet but is looking at 250 x 400, i'm a bit worried about potential weight problems.

The house was built in the mid 1980's and is in Milton Keynes, if anyone has encountered this before please point me in the right direction

cjbombero

P.S - It definately isn't chipboard and its origional and throught the entire house.

MrSpoon · 03-07-2008

"Particle Boards

Particle Board is basically the substitute for Plywood, black board solid wood panels.

Basically Particle Boards is an agro based panel products and is manufactured both in plain and prelaminated quality.

Particle Board is a reconstituted wood panel product. Wood or agro residue is converted in to chips in the process of chipping and milling. This is followed by drying where excess moisture is reduced and uniformally controlled. Dryed chipsare mixed with synthetic resin in the mixing process, thereby forming chips mats of three layer constituency. the Particle mats are pressed and boards are cured in a heated pres thore with a temperature up to 180 degree and then boards are trimmed to desired size and thickness."

is that the stuff?

smokie899 · 03-07-2008

had that proplem a few weeks ago (NIGHTMARE) from a council house bath with shower above it was leaking but the guy only wanted the wall replaced on the long side of the bath replaced as that was were the leak was so start to take tiles off was goin to remove rotten plaster board the n reboard and seal then tile when all had dried out. thing being there was no plaster board just what you found very like compressd hay that is the only way i can describe it and shock horror no joists. the house was a single brick build with this stuff used as breze block and for stud walls. the crazy 80s. only way round it as the guy did not want to replace wall as bedroom next room would be affected was to cut above the damp area then dig allthe damp out left to dry outfor a week so there was about 6ft of solid tiled wall above and 2ft of litterly nowt belowand no way of fixing joists. put marine grade ply 1\2"in the cavity of wall stuck with expanding foam as this stuff is uneven and not much will stick to it that will strengthen the bedroom side wall as you could have poked your fingerthourgh into the b\room. (bath had been removed prior).then put batton on b\room floor level with exsisting wall then ply boarded the wall. glued and screwed with one joint down the middle of wall to try and keep as solid as possible.tanked and tiled turned out very solid no movement. but remember this was done on the cheep i recomended replaceing wall from start i dont do botched jobs but i can so no future probs with it as there is no weight on it and never will be

cjbombero · 05-07-2008

That seems to be the stuff! Like you say you poke into the wall in the bathroom and get all the way into the bedroom

There isn't any water penetration around the shower area and although I would like to board it out the shower cubicle has been built exactly 750 sq so adding sheets will cause more problems.

Anyone know what kind of weight limits these particle boards have? Should I prime the surface first and what ady would you use (spf?)

Thanks for the help

cjbombero

**Dave** · 05-07-2008

Particle/osb boards are not suitable backgrounds for tiling to.......If you glue & screw a 6mm cement backer board to it then it will be fine..........

cjbombero · 05-07-2008

Maybe thats not the substrate, although all the clues point in that direction. It seems strange that both the en-suite and bathroom have been tiled onto for over twenty years and the whole estate is the same apparently. Maybe it could be something else?

If I board the walls out I won't be able fit the shower tray in as the enclosure is only 750 x 750. If I re-skim the walls with a fresh coat of plaster would that help??

cjbombero

**Dave** · 05-07-2008

Can you post a pic and we will see if we can indentify the type.....if you can skim it then it's not OSB.....

cjbombero · 05-07-2008

I'll try and get one to post, I am planning on going back for another look and to take some of the tiles off round the shower. There is already a skimmed layer of plaster on the current boards which makes me even more confused.

cjbombero

Wylie · 07-07-2008

This is going to be know help but i think i have seen the same board,i was asked to plaster the stuff it was dark brown and a hairy sort of look to it probably a wonder board in its day,i would replace or cover it over

cjbombero · 08-07-2008

Yep sounds like the stuff! The guy has checked and its definately particle boards, they make the entire wall about 2 inches thick! I've spoken to the customer and i'm going to board the walls out with 6mm hardi, because the shower tray only just fits in the recess i'm going to have the tray installed and then board down to it. Will I get away with this?

I've suggested tanking the shower out to protect the walls a little more, just depends if i can squeeze a little more money out after he has just bought boards.

cjbombero