ᐅ Concrete slab with perimeter insulation beneath – "soil" !!!URGENT!!! PICTURE
Created on: 15 Aug 2019 21:21
S
StrobelHello,
I have a problem. We bought a house that had a masonry extension (strip foundation with a thin concrete layer of 10cm (4 inches)), which was demolished due to its construction and condition, leaving only the strip foundation (80cm (31.5 inches) deep) remaining.
Now a larger extension is being added, and the mason has extended the strip foundation. According to the structural engineer, the new foundation should be built with an 18cm (7 inches) layer and 2 layers of Q257 reinforcement. Underneath, there should be perimeter insulation. When I visited the construction site, I found the following (see pictures).
Under the perimeter insulation, there is regular "soil," topsoil that I removed during gardening and which the mason has apparently used. The perimeter insulation is also not laid evenly or fully as intended. That can’t be right. Is it installed correctly? Concrete is scheduled to be poured tomorrow. Are there regulations requiring filler sand underneath? I also thought a vapor barrier membrane would be necessary. Please help.
Additional info:
A timber frame will be installed on the foundation. No ground survey is available. Old strip foundations from the previous extension have been there for 30 years.
I have a problem. We bought a house that had a masonry extension (strip foundation with a thin concrete layer of 10cm (4 inches)), which was demolished due to its construction and condition, leaving only the strip foundation (80cm (31.5 inches) deep) remaining.
Now a larger extension is being added, and the mason has extended the strip foundation. According to the structural engineer, the new foundation should be built with an 18cm (7 inches) layer and 2 layers of Q257 reinforcement. Underneath, there should be perimeter insulation. When I visited the construction site, I found the following (see pictures).
Under the perimeter insulation, there is regular "soil," topsoil that I removed during gardening and which the mason has apparently used. The perimeter insulation is also not laid evenly or fully as intended. That can’t be right. Is it installed correctly? Concrete is scheduled to be poured tomorrow. Are there regulations requiring filler sand underneath? I also thought a vapor barrier membrane would be necessary. Please help.
Additional info:
A timber frame will be installed on the foundation. No ground survey is available. Old strip foundations from the previous extension have been there for 30 years.
Is the state shown in the photos really the final condition, just before pouring the concrete?
Why doesn’t the insulation extend all the way to the formwork, and why are there areas left uncovered? And why does it form a skirt towards the existing structure but not on the outside? Also, as far as I know, the bottom strips should be installed the opposite way when using perimeter insulation—and especially not aligned in a straight line, but usually staggered relative to each other. Otherwise, there is a risk that cracks may develop later in the concrete along the strips.
The plastic sheet is meant to prevent the concrete from losing water downward. With proper curing afterwards, I don’t see this as too critical, but one naturally wonders why this was skimped on—the 50€ should be affordable.
Regarding the "topsoil": the slab will rest later on the footings. Unless you have just excavated and loosened the soil between the footings, this should not be a problem.
Why doesn’t the insulation extend all the way to the formwork, and why are there areas left uncovered? And why does it form a skirt towards the existing structure but not on the outside? Also, as far as I know, the bottom strips should be installed the opposite way when using perimeter insulation—and especially not aligned in a straight line, but usually staggered relative to each other. Otherwise, there is a risk that cracks may develop later in the concrete along the strips.
The plastic sheet is meant to prevent the concrete from losing water downward. With proper curing afterwards, I don’t see this as too critical, but one naturally wonders why this was skimped on—the 50€ should be affordable.
Regarding the "topsoil": the slab will rest later on the footings. Unless you have just excavated and loosened the soil between the footings, this should not be a problem.
K
KlausiMausi16 Aug 2019 06:00Are you building a garden shed???? Then that's enough!
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