ᐅ The strip foundation has developed a crack.

Hello, greetings from Russia.

I am building my house here. Temperatures reach up to +45°C (113°F) in summer and down to -20°C (-4°F) in winter. Two years ago, I poured the foundation with 18 mm (0.7 inch) reinforcing steel inside.

Groundwater appears already at 50 cm (20 inches) depth, so I raised the foundation. It is 50 cm (20 inches) deep and 50 cm (20 inches) high.

Now I have noticed a crack that was not there last year. I am not exactly sure of the cause, but first, I had 200 cubic meters of soil delivered and raised the plot. I suspect the groundwater at depth froze.

The crack runs from the top down to about half the height of the foundation, as if it was pushed up from below.

My question is, how dangerous or problematic could this crack become? I am considering pouring a 15 cm (6 inch) high slab completely over it, including on the foundation.

Shouldn't a foundation be frost-resistantly established at 80cm (31.5 inches) deep to prevent exactly this kind of problem?

Yes, unfortunately, I didn’t get around to raising the plot at the time because I was in Germany, and then the whole Corona situation started.

Now I have raised it, so it should no longer be at risk of freezing.

I am wondering if a 15–30cm (6–12 inch) thick concrete slab on top of the foundation would level things out again.

Or do you have any recommendations on how you would proceed?

Peug408 schrieb:

Or are there any recommendations on how you would proceed?

I would ask someone on site who is knowledgeable about this. Even if you have placed soil on top, the foundation is still in water.

Peug408 schrieb:

I was thinking of pouring a 15cm (6 inches) high slab completely over it, including over the foundation.

Don’t just pour a slab on top without proper preparation. A clean, layered construction needs to be done first. I believe the soil layer (topsoil?) was actually counterproductive. It doesn’t look load-bearing.

Please share some information about the soil conditions. There might have been different settlements.

A reinforcement steel bar of 18mm (0.7 inches)?

At -20°C (-4°F), the construction company in the area should have experience with how deep to build frost-resistant foundations.

Are there any photos of the foundation construction?

Hello,
Yes, the topsoil is terrible. There is a river nearby, so the groundwater is very close to the surface.

The soil is sticky and very hard, so digging with a shovel is impossible. However, I dug down about 80cm (31.5 inches) and added 30cm (12 inches) of gravel, and the groundwater didn’t rise anymore.

I think I should have anchored steel posts 2 meters (6.5 feet) deep, but the neighbor’s house doesn’t even have a foundation; it stands on bricks, and none of his walls have any cracks.