Metal behind plaster in ceiling

[agilde]

Hello!

I was helping a friend install some lights in their apartment from the 1930s. We installed the light in the hallway without any problems, but when we were trying to install a light in the kitchen, we hit metal after only about 2 cm. The ceiling consists of a few centimeters of plaster, followed by something more solid. In my own apartment, which is also from the 1930s, it seems I have brick in the ceiling, but I don't think that's the case here because when we drilled in the hallway and got a hold, the dust wasn't red-orange like it usually is when drilling into brick.

The question is, what kind of metal could it be that you encounter after only about 2 cm? If it was in a concrete building, I would continue without hesitation since I would know it was just reinforcement, but it feels strange that there would be reinforcement directly under the plaster. We drilled several holes in a row; in one, we didn't get a hold at all, and in the others, we hit metal. My concern is that it might be something that actually has a function, such as metal pipes for electrical wiring.

 

[jonaserik]

Rebar, move the hole approximately 2-3 cm diagonally from the current position, the bars are positioned in length and crosswise in the vault.

 

[El-Löken66]

Hello!

Was helping a friend install some lights in their apartment from the 1930s. We drilled up the lamp in the hallway without any issues, but when we tried to drill up a lamp in the kitchen, we encountered metal after about 2cm. The ceiling consists of a few centimeters of plaster, followed by something more solid. In my own apartment, which is also from the 1930s, I seem to have brick in the ceiling, but I don't think that's the material here because when we drilled in the hallway and got a hold, it wasn't at all the red-orange color of the dust that it usually is when drilling in brick.

The question is, what kind of metal can you encounter already after about 2cm? If it was a concrete building, I would have continued without hesitation, knowing it was just rebar, but it feels spontaneously strange that it would be rebar right under the plaster. We drilled several holes in a row, in one we didn’t get any grip at all and in the others, we encountered metal. My worry is that it might be something that actually has a function, such as metal pipes for electrical wiring.

If it's an arch, then it's probably something load-bearing and you won't be able to avoid it. But it's probably just a small hole you need to make, so I don't think the metal drill bit will cause much damage.

 

[agilde]

Rebar, move the hole about 2-3 cm diagonally from the current one, the rebar is oriented lengthwise and crosswise in the arch

That's what I thought, but it felt so strange that it's located directly under the plastering. But maybe it's not. What is meant by arch?

 

[cpalm]

Can also be a beam - in a house from the 30s, there can be embedded beams in places you wouldn't expect today, not uncommon with old railway rails.