What is in the basement wall? How should I think about drilling/plugging?

[mickeforsberg]

Hello everyone!

I was fixing up a storage room in the basement and anchoring a shelf to a basement wall. When I drilled, the drill sank 3.5 cm into the wall before reaching the concrete (if it is concrete). The wall overall sounds very hollow everywhere you knock.
Now, I haven't torn into it more than enlarging the hole from the drilling, but after a layer of plaster material, there is also a layer of some kind of wood shavings? It is white on the outside but if I break a piece, it is brown in the middle. It really looks a lot like wood. Is this normal in an... exterior basement wall?

How should I proceed when plugging? Should I just disregard the 3.5 cm layer of "loose" plaster and simply drive a plug into the concrete?

The house is from 1946.

 

[Magnus E K]

Sounds like träullit. Yes, if there is concrete behind, drill into it and fasten with long plugs and screws.

 

[mickeforsberg]

Sounds like träullit. Yes, if there's concrete behind it, drill into it and secure with long plugs and screws.

Ah, you're right about that! A quick Google search says it was invented in 1946, so it was ultramodern for our house back then. That said, I still don't know when it was installed.

But in a basement, I mean, does it work?

 

[jonaserik]

The best approach is to drill in 3 pieces for dowels and attach a board/stud, and then secure what you want to mount. If it's too tight, the plaster might give way and sink in; träullit is hard and crumbles easily.

 

[mickeforsberg]

Best is to drill in 3 for plugs and attach a board/regulation board and then fasten what you want to put up. If it's too tight, the plaster might give in and sink, träullit is hard and crumbles easily.

Good tip! Yes, both the plaster and träullit crumbled quite a bit.
I actually just need to anchor a free-standing shelf with perforated metal tape or something similar so nothing happens if the children decide to do something. But if I push the plug past these 3.5 cm, it shouldn't matter if it crumbles, right?

 

[jonaserik]

For tip-over protection, long wood screws are sufficient, but remember they need to penetrate the wall at least 7 cm + 3.5 cm. Normally, in heraklit (which is crap), the screws/bolts need to be thick and penetrate at least 10 cm, as screws/bolts can bend because heraklit doesn’t hold up well against lateral force.