WTH are my walls made of, and how do I fix shelves to them?

[Medium_Rare]

Hello all, hopefully this is the right forum for this.

Recently moved into a new place, and I want to put up some shelves in an upstairs storage cupboard. The place was built in 1998 as part of a Housing Association estate, so I assumed it would be pretty standard construction with plasterboard walls and probably studwork behind.

Get el cheapo stud finder from B&Q, start scanning the walls. Ideally want shelves at right angles, one set on the back (party) wall and one set on the adjacent partition wall. Stud finder can't find anything meaningful on any of the walls (apart from a/c, apparently everywhere), tapping is inconclusive and fridge magnets don't respond to anything.

Next step, get out the drill and make some investigative holes. Go through the plasterboard on the party wall, and immediately hit the masonry behind- I'm guessing this means it's dot and dab, but the odd thing is that the plasterboard layer is very thick- looks like two sheets of 18mm board. Is this normal? Why would you have a double layer of pb on an internal wall?

I repeat the exercise on the partition wall- the drill keeps on going, and I expect to go into the void in the studwork but there is none- I just go straight through the wall into the adjacent room. It looks like this wall is made of solid plasterboard, and is pretty thick too, easily 3 layers of 18mm plasterboard sandwiched together. Again, is this normal? I can't find any reference to internal walls being built like this on the net. It's not like this is a tiny cupboard either, it's a good 4ft square.

So, essentially two questions

1) Are my walls normal?

2) How do I go abut fixing shelves to them?

I've been looking a specialist drywall anchors for fixing to dot-and-dab walls, but they seem like they're intended to go through a single layer of plasterboard before they fix into the masonry behind. With mine they'd need to clear almost two inches of board and air gap before the wall behind, so I'd be concerned that the long 'un-anchored' part would bend and then deform the plasterboard over time. With the partition wall I accept that it just might not be possible to put any great weight on it, but any ideas are gratefully received.

 

[freddiemercurystwin]

Your party wall is just masonry with two layers of PB dot and dabbed on to provided additional sound proofing- nothing usual there. Longer screws and wall plugs that go into the masonry will work fine.

Your internal walls are a different matter, this is a not very common but not unheard of method of construction that favours the developer seeing as its cheap and saves space. A layer of standard PB on each side d&D to the central layer which is (or should be) a bit thicker/harder and a timber perimeter frame to hold it in position. If you want to hang anything heavy off them then you can't basically. Or you need to fit a sheet of plywood or similar first fixed from the other side. Or build a stud wall with plasterboard on the side you want to fit your shelves to and fit to the new stud wall lining.

BTW do you own this house or are you renting? Cos if you're renting then have you asked the landlords for permission?

 

[foxhole]

Could be honeycomb plasterboard [46mm thick] two sheets separated by card honeycomb, though usually reserved for office walls.

 

[Medium_Rare]

Could be honeycomb plasterboard [46mm thick] two sheets separated by card honeycomb, though usually reserved for office walls.

Nope, definitely solid all the way through, and a little thicker than 46mm I think...

BTW do you own this house or are you renting? Cos if you're renting then have you asked the landlords for permission?

Ha, no, these are my own walls I'm putting huge holes in!

Good to know that they're nothing wildly unique, construction-wise. The dual plasterboard layer on the party wall makes sense, the soundproofing between these houses is surprisingly good. Will I be OK just using regular rawl plugs and suitable length screws then?

Many thanks to both for your replies.

 

[freddiemercurystwin]

Yes but of course your rawl plugs need to be in the wall not the boards.