Cracks in the interior wall in a hillside basement

[Laniel]

Hello!

I have two cracks in the wall of my boiler room.
They are quite long, and you can't see anything on the outside of the house, the part of the wall that is above ground. I guess that previous owners may have stacked firewood carelessly and created a small crack that has since grown. I seem to remember it was there when we moved into the house a little over six months ago, but there's been so much to think about that I don't remember definitively.

See pictures of the cracks.

How do I fix this in the best way? I don't care if it's aesthetically pleasing; it just needs to hold well.

 

[Stefan N]

Such cracks do not come from a little wood stacking, that's how it is with this type of walls.

 

[Laniel]

So should I just fill it in with plaster or concrete? Or will it come up again, so I might as well leave it as it is?

 

[Claes Sörmland]

Hard to know. It has cracked because it has moved. But chip away the plaster, clean everything loose with a chisel, vacuum, and apply new mortar in a couple of rounds. In a few years, you'll have the answer whether it was a one-time thing or if the wall continues to move.

 

[jawen]

How should I fix this in the best way? I don't care if it's aesthetic, it just needs to hold well.

All old cast & masonry basements get some crack, & since yours are in the boiler room, they most likely came from the wall expanding a bit from the heat during the season when the boiler was running more.

Then the walls cool down & shrink.
It doesn't look like subsidence has caused yours!
Brush thoroughly with a wire brush & knock off any loose plaster, & fill with regular Repair Mortar (it is too thin to repair with plaster).

You likely have "scale walls" in the basement, i.e., 2 layers of masonry/cast walls with air in between, which is why you don't see any cracks from the outside.

 

[Laniel]

OK.

So I don't need to worry about anything collapsing? It's mostly aesthetic and likely due to temperature differences?

 

[Lolpodajj]

OK.

So I don't need to worry about anything collapsing? It's mostly aesthetic and probably due to temperature differences?

Hi,

How did it go for you here?
I also have a '70s house with cracks here and there.

 

[Laniel]

Hello,

How did it go for you here?
I also have a house from the 70s with cracks here and there

I filled the big cracks with C-bruk. I also have some cracks the size you sent pictures of, but I haven't bothered with them. They are too narrow to fill with C-bruk in my opinion. But maybe someone else here has better arguments about them.