Pet1234
2020-04-29 17:38:10
- #1
Hello dear ones,
I urgently and promptly need your advice.
I am building a bungalow without a basement with Heinz von Heiden (GÜ).
Until today, the excavation company was there to create the foundation cushion. The plot has a slope of 90 cm over a length of 22 meters along the street. Directly in the construction area, this height difference is not so large (30 cm), since something was already there, covered with soil, and the strip foundations were removed by the excavation company to a depth of about 50-60 cm. The soil surveyor did not detect this; for him, everything was fine. I found out in advance from neighbors. The plot slopes down again about 90 cm at the back.
According to the construction contract, Heinz von Heiden is responsible for a foundation cushion of 30 cm including excavation and an additional 1 meter all around the house.
The contract states the following about earthworks, among other things:
"The existing topsoil in the area of the house as well as 1 meter extending around it will be removed to a depth of up to 30 cm and stored laterally on the property. Then a compacted foundation cushion up to a thickness of 30 cm will be built. The overhang of the foundation cushion (sand slab) from the outer edge of the base plate amounts to 1 meter corresponding to the topsoil removal...
If local increased thickness occurs due to installation of greater heights and additional excavation down to the load-bearing foundation level, these will be charged separately.
Increased thicknesses of the foundation cushion can only be determined after reviewing the soil survey and the determination of the house's height location as well as the local conditions.
The calculation basis for stripping the topsoil in the setback areas and any required pipe trench and frost protection excavation (depending on the chosen foundation variant) is soil class 2-3 according to DIN 18300.
Deviating soil classes, soil replacement, or a foundation type deviating from the foundation variant are at the expense of the client."
In the foundation section it states, among other things:
"Your house will stand on secure foundations. The ground floor slab will be made of concrete quality C25/30 (WU concrete) according to the type statics and founded frost-proof with frost skirts made of normal concrete.
The following assumptions are the basis for the type statics:
Minimum allowable stiffness coefficient 20 MN/m² as well as soil pressure 200 KN/m²
Maximum groundwater level at least 100 cm below the planned foundation or floor slab
Use with heated living space and indoor temperatures above 10 degrees
Flat terrain.
The ground floor slab will be made with a thickness of about 18 cm."
Now to my problem.
Due to the height difference, the excavation company made an offer, in addition to breaking up the existing strip foundations, to fill the terrain: gravelly sand delivered by additional soil removal, installed according to the profile and compacted in layers.
This also applies in the terrace area, which I had excavated at the same time.
Since I currently live only a few steps from the construction site, I am there several times a day observing the process.
Thus, under the ENTIRE area of the house, only sand was filled and compacted. Since it is very dry at the moment, after about halfway through they fetched water to moisten it because the sand could not be compacted.
So the current build-up under the house and 1 meter around the planned house is exclusively sand; first 032 about half, then when it could not be compacted, 045 was added on top.
To me, it is a pile of sand where the footprints immediately sink in even with light walking. Also in the area of the lowest 30 cm, after the clay soil, no frost protection, concrete recycling, or any solid material was added. The entire build-up where the plot was lower, we are talking about 95 cm, consists of dry sand. Below that is clay soil.
When I expressed my concern to the foreman and also the head of the excavation company that this is not a load-bearing foundation for a terrace and especially not for a house, they avoided answering and referred me to the site manager. The excavation company boss tried to convince me that it is "certified frost protection sand" which is just as effective as proper frost protection. And they already took the better 045 since the 032 would not bind.
At another Heinz von Heiden house, I saw reddish frost protection/sand with more stones compressed throughout the entire area and height, which was also properly firm and soil-like. My sand is yellow, very fine, and as I said, to me a big sand pile.
The excavation company boss answered my question why this reddish frost protection was not used in my case by saying he would have had to travel further and that it’s a matter of cost. Nobody asked me!! The sand pit where he got the sand now is 3 km away; there is no red frost protection there. But it could have been delivered and ordered, according to the sand pit employee.
The employee at the sand pit also confirmed that the sand that was put in at my site is not suitable for foundation.
In the construction contract, I read that only the overhang of the foundation cushion, the 1 meter sand slab, is specified. Otherwise, I find no information about the material of the foundation. But there must be DIN standards regarding the type of foundation on which such a house must stand.
The next problem I see is in the installation of the surrounding frost skirt. According to the excavation company, this apparently goes only 60 cm deep; it is a special formwork or something similar from Heinz von Heiden.
On the right side of the property, after 40 cm, there is load-bearing clay soil.
On the left part under the house, as mentioned, due to the 95 cm of filled sand, there is clay soil only after 95 cm. That means the frost skirt would be built in the filled sand, provided the whole dirt does not fall back into the excavation! That cannot be right!!!
Today at noon, an inspector commissioned by the excavation company was here to check the compaction. Of course, everything was compacted and load-bearing!!!
I shared my concerns with him regarding the frost skirt in the sandy soil. He said the frost skirt should be between 80 and 100 cm depending on the height level. We have a height of 215. How does Heinz von Heiden come up with going only 60 cm deep??
Thank you in advance for your opinion.
Oh yes, next Wednesday the shell construction company is coming and wants to build the frost skirt and floor slab within two days.
I urgently and promptly need your advice.
I am building a bungalow without a basement with Heinz von Heiden (GÜ).
Until today, the excavation company was there to create the foundation cushion. The plot has a slope of 90 cm over a length of 22 meters along the street. Directly in the construction area, this height difference is not so large (30 cm), since something was already there, covered with soil, and the strip foundations were removed by the excavation company to a depth of about 50-60 cm. The soil surveyor did not detect this; for him, everything was fine. I found out in advance from neighbors. The plot slopes down again about 90 cm at the back.
According to the construction contract, Heinz von Heiden is responsible for a foundation cushion of 30 cm including excavation and an additional 1 meter all around the house.
The contract states the following about earthworks, among other things:
"The existing topsoil in the area of the house as well as 1 meter extending around it will be removed to a depth of up to 30 cm and stored laterally on the property. Then a compacted foundation cushion up to a thickness of 30 cm will be built. The overhang of the foundation cushion (sand slab) from the outer edge of the base plate amounts to 1 meter corresponding to the topsoil removal...
If local increased thickness occurs due to installation of greater heights and additional excavation down to the load-bearing foundation level, these will be charged separately.
Increased thicknesses of the foundation cushion can only be determined after reviewing the soil survey and the determination of the house's height location as well as the local conditions.
The calculation basis for stripping the topsoil in the setback areas and any required pipe trench and frost protection excavation (depending on the chosen foundation variant) is soil class 2-3 according to DIN 18300.
Deviating soil classes, soil replacement, or a foundation type deviating from the foundation variant are at the expense of the client."
In the foundation section it states, among other things:
"Your house will stand on secure foundations. The ground floor slab will be made of concrete quality C25/30 (WU concrete) according to the type statics and founded frost-proof with frost skirts made of normal concrete.
The following assumptions are the basis for the type statics:
Minimum allowable stiffness coefficient 20 MN/m² as well as soil pressure 200 KN/m²
Maximum groundwater level at least 100 cm below the planned foundation or floor slab
Use with heated living space and indoor temperatures above 10 degrees
Flat terrain.
The ground floor slab will be made with a thickness of about 18 cm."
Now to my problem.
Due to the height difference, the excavation company made an offer, in addition to breaking up the existing strip foundations, to fill the terrain: gravelly sand delivered by additional soil removal, installed according to the profile and compacted in layers.
This also applies in the terrace area, which I had excavated at the same time.
Since I currently live only a few steps from the construction site, I am there several times a day observing the process.
Thus, under the ENTIRE area of the house, only sand was filled and compacted. Since it is very dry at the moment, after about halfway through they fetched water to moisten it because the sand could not be compacted.
So the current build-up under the house and 1 meter around the planned house is exclusively sand; first 032 about half, then when it could not be compacted, 045 was added on top.
To me, it is a pile of sand where the footprints immediately sink in even with light walking. Also in the area of the lowest 30 cm, after the clay soil, no frost protection, concrete recycling, or any solid material was added. The entire build-up where the plot was lower, we are talking about 95 cm, consists of dry sand. Below that is clay soil.
When I expressed my concern to the foreman and also the head of the excavation company that this is not a load-bearing foundation for a terrace and especially not for a house, they avoided answering and referred me to the site manager. The excavation company boss tried to convince me that it is "certified frost protection sand" which is just as effective as proper frost protection. And they already took the better 045 since the 032 would not bind.
At another Heinz von Heiden house, I saw reddish frost protection/sand with more stones compressed throughout the entire area and height, which was also properly firm and soil-like. My sand is yellow, very fine, and as I said, to me a big sand pile.
The excavation company boss answered my question why this reddish frost protection was not used in my case by saying he would have had to travel further and that it’s a matter of cost. Nobody asked me!! The sand pit where he got the sand now is 3 km away; there is no red frost protection there. But it could have been delivered and ordered, according to the sand pit employee.
The employee at the sand pit also confirmed that the sand that was put in at my site is not suitable for foundation.
In the construction contract, I read that only the overhang of the foundation cushion, the 1 meter sand slab, is specified. Otherwise, I find no information about the material of the foundation. But there must be DIN standards regarding the type of foundation on which such a house must stand.
The next problem I see is in the installation of the surrounding frost skirt. According to the excavation company, this apparently goes only 60 cm deep; it is a special formwork or something similar from Heinz von Heiden.
On the right side of the property, after 40 cm, there is load-bearing clay soil.
On the left part under the house, as mentioned, due to the 95 cm of filled sand, there is clay soil only after 95 cm. That means the frost skirt would be built in the filled sand, provided the whole dirt does not fall back into the excavation! That cannot be right!!!
Today at noon, an inspector commissioned by the excavation company was here to check the compaction. Of course, everything was compacted and load-bearing!!!
I shared my concerns with him regarding the frost skirt in the sandy soil. He said the frost skirt should be between 80 and 100 cm depending on the height level. We have a height of 215. How does Heinz von Heiden come up with going only 60 cm deep??
Thank you in advance for your opinion.
Oh yes, next Wednesday the shell construction company is coming and wants to build the frost skirt and floor slab within two days.