cant figure out what my wall is made from

[olyforprez]

hi

i've just moved in to my house and i cant seem to figure out what the walls under the stairs are made of. after drilling some holes it seems to be some sort of chipboard but its about 3" thick and looks a bit like compresssed hay.

the house was built in the early 90's and is just a fairly normal semi

could it be somthing to do with fireproofing?

just trying to figure out what fixings to use when putting shelves up etc.

any help would be greatly apreciated

thanks
oly

 

[JohnD]

if it's grey, it's a cement and compressed straw board, a sort of lightweight block suitable for inner skins and partitions. I have never used it myself, it is supposed to be fairly good for insulation. Otherwise it might just be strawboard, or oriented strand board, but it sopunds too thick for OSB.

If you want to fix things to it, it will not be very strong, but I recommnend that you drill a good-sized hole that will take your screw and plasplug, then squirt no-more-nails or similar into the hole, and push the plug into it. When it sets, overnight, it will give quite a firm setting that will not crumble or turn.

It's a good way to fix to poor walls. I wouldn't fix anythinh heavy to it though. You can fix a batten using a number of such plugs and screws, and fix to the batten.

 

[olyforprez]

thanks johnd

just done a picture search on strawboard and it looks like thats what ive got.

now i know that i shouldn't i really want to hang a shelf on it (typical)

with it being the wall under the stairs i'm goung to try and get to the back of it and bolt through with some big washers to spread the load.

am i being too optimistic or is this just crazy enough to work?

 

[JohnD]

I would go for vertical battens for each bracket, screwed as described, or a piece of ply fixed to the wall, with the brackets fixed to it. You can't use floating shelves as they need a very strong wall.

Forcing the adhesive into the hole binds the fibres together. I would do that even if you are bolting through. Let it harden well before loading it. Use big washers each side to prevent pull-through of the bolts.

 

[noseall]

You have Stramit board or an equivalent.

Careful, there are hollowed out ducts or conduits throughout the board through which to run cables.