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.
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.
Hello,
The concrete slab is now curing, so far so good.
Now regarding the topsoil, I only replaced the topsoil with gravel in the area where the slab is.
Does this also need to be done along the strip foundation?
What are the benefits of that, or more precisely, what are the disadvantages if the soil touches the concrete?
There is a plastic sheet between them, or there was one—it is now torn in some places.
The concrete slab is now curing, so far so good.
Now regarding the topsoil, I only replaced the topsoil with gravel in the area where the slab is.
Does this also need to be done along the strip foundation?
What are the benefits of that, or more precisely, what are the disadvantages if the soil touches the concrete?
There is a plastic sheet between them, or there was one—it is now torn in some places.
A foundation depth of 80 cm (31 inches) is definitely too shallow for your base. Especially in Russia, with the frost conditions there. The foundation must be placed below the frost line, and I would expect around 2.00 m (6 ft 7 in) to be necessary. Here in Saxony-Anhalt, we have had frost reach depths of 1.20 m (4 ft).
I would say this is a settlement crack. A frost-related damage. Building on that will be difficult.
It might work, but it can also shift. Then the walls and the concrete slab of your house will crack.
I built my terrace with a similar design. I went 1 m (3 ft 3 in) deep with the strip foundation there.
I would say this is a settlement crack. A frost-related damage. Building on that will be difficult.
It might work, but it can also shift. Then the walls and the concrete slab of your house will crack.
I built my terrace with a similar design. I went 1 m (3 ft 3 in) deep with the strip foundation there.
In the south of Russia, it’s not usually that cold; temperatures can sometimes drop to -20°C ( -4°F ), but that is rare.
Currently, we have temperatures up to +15°C (59°F) again. Last week was colder.
The excavation was about 90cm to 100cm (35 to 39 inches), but the excavator operator wasn’t very precise.
The foundation itself has the correct height of 100cm (39 inches); the problem was apparently that 50cm (20 inches) of it was underground.
The other 50cm (20 inches) was sticking out above ground.
The rest is a gravel layer at least 40cm (16 inches) thick, which also pushes the groundwater away.
I think that since I raised the ground around the foundation by 50cm (20 inches), nothing should freeze anymore.
At least, that’s what I hope.
Currently, we have temperatures up to +15°C (59°F) again. Last week was colder.
The excavation was about 90cm to 100cm (35 to 39 inches), but the excavator operator wasn’t very precise.
The foundation itself has the correct height of 100cm (39 inches); the problem was apparently that 50cm (20 inches) of it was underground.
The other 50cm (20 inches) was sticking out above ground.
The rest is a gravel layer at least 40cm (16 inches) thick, which also pushes the groundwater away.
I think that since I raised the ground around the foundation by 50cm (20 inches), nothing should freeze anymore.
At least, that’s what I hope.
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