Is it blue concrete?

[Tobiblas]

Hello,

I tore down a wall in the basement and when I removed a door frame, the concrete shown in the picture was revealed. Is it blåbetong or something else dangerous? There is a sauna on the other side of the wall that is no longer used. The house is from 1928. I have no idea when the wall was built.

 

[Luddis_1]

Yes, it could possibly be blue concrete, but what do you think is so dangerous? What do you want to do?

Plaster it again and paint with suitable paint, then if you're paranoid, get a radon meter and see how the situation stands.

 

[Fixar_Krille]

If it is blue concrete, it should be porous like siporex? I don't think it looks like blue concrete but more like gråsuggor (cement blocks)

 

[Oaken]

It is not blue concrete; it's slag block that was common in the 1920s-1940s.

 

[Tobiblas]

It's not blue concrete, it's slag blocks that were common in the 20-40s.

Sounds reasonable. It's porous and seems to have some mixed stones in it. However, the bluish color made me suspect blue concrete. Maybe I'll do a radon measurement just to be safe...

 

[Oaken]

Sounds reasonable. It is porous and seems to have some mixed stones in it. However, the bluish color made me suspect blue concrete. Maybe I'll do a radon measurement just to be safe...

If you do a radon measurement and it shows radon, the radon will not come from the slag boards.

 

[MariaCCD]

It is not blåbetong, it is slaggblock which were common in the 20-40s.

Hi, I wonder what are slaggplattor? We live in an apartment built in 1950/60 that has walls completely impossible to hammer a nail into. Always have to drill & plug, nothing else works. Black dust often comes out, and suddenly it can still be porous, making the hole bigger than intended, requiring building permission before plugging. So it's quite troublesome.
What material could it be? Is the black stuff risky to inhale when drilling?
Thanks in advance
Marie

 

[BirgitS]

Hello, I wonder what slaggplattor are? We live in an apartment built in 1950/60 that has walls that are completely impossible to hammer a nail into. Always have to drill & plug, nothing else works. Black dust often comes out, and then suddenly it can be porous anyway, and the hole gets bigger than intended, requiring a building permit before plugging. So it's quite troublesome.
What material could it be? Is the black dust risky to inhale while drilling?
Thanks in advance
Marie

Slag is a byproduct of metal handling, see here: https://sv.wikipedia.org/wiki/Slagg

Whether it is slagsten or blåbetong in your walls is hard to know. It might be easiest to ask the board or neighbors.

It is unsuitable to inhale any kind of construction dust.