Is this wall load-bearing? (lightweight concrete)

[Hatmpatn]

Hello! We have a room with an oil tank in it, and we would like to cut up the oil tank and then tear down the wall to the adjacent room. The wall is made of lightweight concrete (we believe it is 10cm thick, but we will confirm this in the coming days).

A nightmare would certainly be to tear down a load-bearing wall, and it seems like the question is a bit too simple to ask a structural engineering firm. So I thought I’d check here if someone can point me in the right direction to determine if this wall is load-bearing or not?

Image 1 is a drawing, 2 is the technical description, and 3 is a picture of the wall from the tank side that we want to tear down.

 

[Mats-S]

A little more information might be needed

- When was the house built?
- What is the structure above the wall made of, concrete?
- How thick is the wall (I know you're going to check that ?

EDIT: I see that it's a concrete structure ;-)

 

[Hatmpatn]

Hello Mats-S and thanks for the response.

The house was built in 1967 and the joists are indeed made of concrete.

Regarding the thickness, I'll measure it this evening.

 

[mexitegel]

The easiest way is to start by checking the thickness. If the wall is 20 cm, it is load-bearing - otherwise not.
Aerated concrete from 67? Is it blåbetong?

 

[Mats-S]

The simplest way is to check the thickness. If the wall is 20 cm, it is load-bearing - otherwise not.
Aerated concrete from 67? Is it blue concrete?

Unfortunately, it's not that simple, in theory yes, in practice no.
Over time houses shift and weights can be redistributed somewhat. Concrete slabs resting on 10cm aerated concrete may have settled over time and placed more and more weight on the wall.

I have personally experienced this phenomenon in a house from the same era as TS, so I know with 100% certainty that it can happen. It was assumed that the aerated concrete wall (blue concrete, as I recall) which was 10 cm was not load-bearing, demolished it ... and experienced large settlements in the floor above because the concrete slab sagged a few centimeters.
No, it didn't collapse, but there were significant consequences on the floor above.

 

[Hatmpatn]

Understood. How can one ensure that there is no significant load resting on this wall, even if it is a 10cm wall (which it probably is) that should not be load-bearing?

It is not blåbetong.

 

[Mats-S]

One way is to brace with strong screw jacks beside the wall, demolish the wall, and then carefully begin to relieve the jacks. If you notice movement on the floor above, you need to tighten up and make a pillar in the middle to handle the tension that has developed over the years.

It's not at all certain that it will settle with you, the wall is quite close to the edge besides, but I just wanted to point out the risk

https://www.google.com/search?q=skruvstämp

 

[Hatmpatn]

One way is to secure with strong screw jacks beside the wall, demolish the wall, and then gradually start unloading the jacks. If you notice movement on the floor above, you should tighten and make a pillar in the middle that handles the tension that has developed over the years.

Not at all certain that it will settle with you, the wall is quite close to the edge as well, but I just wanted to point out the risk

[link]

I like that plan.
To clarify:
1. I buy say two jacks
2. Remove two columns of lightweight concrete blocks at an even distance on the wall.
3. Tighten the jacks in these gaps
4. Demolish the rest of the wall
5. Lower the jacks say a few millimeters
6. See if the ceiling settles and try to follow the jacks

 

[Mats-S]

Assuming that the wall can be considered "non-load-bearing," 10 cm blåbetong.

1. If you're lucky, you might be able to rent cheaply, alternatively second-hand on blocket or similar. Otherwise, you can probably sell them when you're done.

2-3.
- You can place the prop about 50 cm into the large room if you have a hard rigid floor there, like a concrete floor. This will make demolition easier.
- Distribute the pressure from each prop using a type of 50 cm plank at the bottom and a type of 50 cm rule in the notch at the top.
- It's very important that the prop is steady and firm, tightly screwed. If there's no firm foundation, you'll have to do as you planned, hopefully, it's stable under the existing wall

5.
Gradually relieve the pressure by about 2-3 mm and let a few hours pass in-between. Since you're relieving the prop, you need to place something soft between it and the ceiling so they don't topple over. But initially, they'll probably stay in place because I think you have some downward movement in the floor joist then.
Check doors/walls on the floor above for binding and cracks. Also, have a checkpoint in the middle of the room in the basement to verify the settling.

Don't rush this step, let it take its time so the floor joist stabilizes. Expect a minor settling of maybe 5 mm, but definitely not several centimeters.

Many will probably think I'm exaggerating now, the wall isn't load-bearing... but as I said, in a house this old, you can't say with 100% certainty that no load-bearing has developed in the wall... Better Safe than Sorry ;-)

 

[mexitegel]

Good points, I can only add that it doesn't cost many kronor to rent a stämp. We're talking somewhere around 20 SEK/each/day. In my opinion, it's not worth the hassle of buying/selling if you don't have more projects in progress.

 

[jonaserik]

I like that plan.
To clarify:
1. I buy say two supports
2. Remove two columns of lightweight concrete blocks evenly spaced on the wall.
3. Position the supports in these gaps
4. Demolish the rest of the wall
5. Lower the supports say a few millimeters
6. See if the ceiling settles and tries to follow the supports

Start by removing a stone towards the ceiling, then you will see if the gap towards the ceiling is filled. It is likely a wall (loose) that was built up after the tank was placed, that's how it was done before. The tank was concealed and is probably of a square or rectangular sort. No hatches or openings in the wall for inspection back then.

 

[Matti_75]

Tear it down it's not load-bearing