No studs on drywall?

kavelot

Hi!
I wanted to install a bookshelf on a drywall, so I think it would be advisable to find studs since books are heavy.
I tried with a stud finder (Bosch GMS 120), but it was giving inconsistent results, so I drilled 12 holes (3mm) 50mm apart following a line. All of them had the same pattern: drill for 11mm, then hollow until 30mm, then it hits something that sounds like wood (I didn't try drilling this).

From the face of this wall (bedroom) to the face of the opposite wall (which is a bathroom), there is 125mm.
On the bathroom wall it would not make sense to have pipes (the stud finder also doesn't find any metal).

Any clues what's going on inside this wall? Maybe the studs are horizontal?

Thanks

Calahonda52

is this a timber framed house or block

Feisar

So it's an internal stud partition? As in not facing onto an external wall?

I'd say it's timber studs but what you are hitting is a ground flush to the far side.

kavelot

no, it's an apartment block built in ~2005, external walls are solid bricks


this one I'm asking about is an internal wall shared between bedroom and bathroom, which seems to be ~125mm thick

awec

What do you mean when you say the stud finder had inconsistent results?

Blondini

Sounds like dot and dab maybe?

Feisar

Blondini wrote: »

Sounds like dot and dab maybe?

I was thinking that but it's an internal wall

awec

Blondini wrote: »

Sounds like dot and dab maybe?

Dot and dab is for block walls.

I think it's just likely the OP hasn't found a stud yet.

kavelot

ha, sorry, nevermind
awec is right
I kept drilling a bit more to the side of my line and found it after 2 holes
I think I got unlucky to start right after a stud

thanks for the replies!

kavelot

well, I'm back with something unexpected
I made all the planning for the shelf holes. Some of the holes will match the studs, some will not - for the latter I got a strong drywall anchor.


Cool, so I started drilling the 8mm hole the drywall anchor needs and after 30mm I hit something solid (samething I had hit before). Since now I'm doing 8mm holes, I can see more clearly inside and it looks like concrete (pic attached)!


I'm a bit confused because while investigating what that is I tried:
1) Hammering a nail on it - it went through! (so maybe it's not concrete?)
2) Drilling with the wood drill bit - didn't work
3) Drilling with the concrete drill bit - didn't work
4) Drilling with the concrete drill bit + hammer mode - worked


Now I'm even more confused


Is this concrete?! Behind a drywall?

kavelot

maybe that's a cement board (there are tiles on the other side of the wall)?

Bonzo Delaney

Looks like internal block walls dot and dabbed with plaster board.
Is your spade bit blunt now after hitting the wall in the second pic

astrofool

Is it an external wall or internal wall, ground floor or not?

It looks like concrete, most ground floor walls will be plaster on concrete, some on battens with rockwool/earthwool in between (your picture looks like bits of earthwool pushed out of the way of the hole), others with just dabs of compound (there's usually about 2cm between plaster and concrete on those). Newer builds will use insulated board (plaster backed with rigid foam). Or it could be something else entirely, there's lots of different ways to build a wall