So initially I thought I had a regular plasterboard. But I have a small measuring thing for wall depth, and after drilling a hole it seems it's deeper than 25mm. The plastboard thickness I see is 10 or 13mm online. So I am wondering if I even have plasterboard?

I am very new to this stuff so just sort of guessing. The apartment house is pretty old, I think it was built in 40s/50s. I am drilling the hole to fasten a standing shelf to it so that it doesn't fall over.

Do I just need a longer fastener? How can I determine how long do I need?

1 Answer 1


You almost certainly have plaster over "rock lath" which is a sort of early drywall board with holes in it for plaster to key into. Rock lathed plaster was common during that time--used as a time saving alternative to wood lath, but before taped and mudded drywall became popular. The board was 1/2", and the plaster another 1/2" or so. It's a very robust finish system for a wood-framed wall. Just find a stud and use longer screws.

  • to put the big shelf where I want i'm limited to a specific spot where I have to install it. And there is no stud there
    – StanM
    Aug 23, 2015 at 19:41
  • Thank you - it was rock lath, I ended up using toggle bolt screw to secure it, I didn't have an option for studs, so that one worked out pretty well. I don't think the shelf would tip over even without the screws, but I wanted to be really really sure.
    – StanM
    Sep 20, 2015 at 15:10

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