Hello,
we now have the following "conflict" to resolve.
We are building a 14 x 14.5 m (46 x 48 ft) bungalow. The soil report indicates the following layers:
Layer 1: Topsoil 20 cm (8 inches)
Layer 2: Sand, highly silty, soft to stiff, gray-brown
Layer 3: Sand, highly silty, humus, soft to stiff, dark brown to black-brown
Layer 4: Sand, low silt content, partly silty, medium dense, ...
Recommendation: remove 1 to 1.1 m (3.3 to 3.6 ft) and refill with compacted gravel or a similar material.
Now, a groundworks contractor who has seen our plans pointed out that he was not informed about our planned fill. We actually need to build up an average of 1 m (3.3 ft).
He suggested that it would be sufficient to just strip off the topsoil (and possibly some centimeters of layer 2) to achieve a 1.4 m (4.6 ft) gravel layer underneath the foundation slab. If necessary, the foundation slab could be made a bit thicker and the reinforcement adjusted accordingly. This would save us money.
However, our structural engineer insists that everything must be removed as recommended in the soil report.
Now we are uncertain. Both are professionals.
We will consult other groundworks contractors to see their opinions.
However, this involves a significant amount of money. Has anyone here had experience with a similar case?
we now have the following "conflict" to resolve.
We are building a 14 x 14.5 m (46 x 48 ft) bungalow. The soil report indicates the following layers:
Layer 1: Topsoil 20 cm (8 inches)
Layer 2: Sand, highly silty, soft to stiff, gray-brown
Layer 3: Sand, highly silty, humus, soft to stiff, dark brown to black-brown
Layer 4: Sand, low silt content, partly silty, medium dense, ...
Recommendation: remove 1 to 1.1 m (3.3 to 3.6 ft) and refill with compacted gravel or a similar material.
Now, a groundworks contractor who has seen our plans pointed out that he was not informed about our planned fill. We actually need to build up an average of 1 m (3.3 ft).
He suggested that it would be sufficient to just strip off the topsoil (and possibly some centimeters of layer 2) to achieve a 1.4 m (4.6 ft) gravel layer underneath the foundation slab. If necessary, the foundation slab could be made a bit thicker and the reinforcement adjusted accordingly. This would save us money.
However, our structural engineer insists that everything must be removed as recommended in the soil report.
Now we are uncertain. Both are professionals.
We will consult other groundworks contractors to see their opinions.
However, this involves a significant amount of money. Has anyone here had experience with a similar case?
Payday schrieb:
Getting people together doesn’t help much because no one wants to take responsibility. If they discuss and agree on a procedure, the excavation is carried out, and the site engineer then formally approves the pit in writing, you are legally protected as far as possible. Just sitting together doesn’t work, that’s true, as everyone could just point fingers at each other again. One person has to take responsibility, and that can only happen if they have inspected and approved the work on site; otherwise, they can always find an excuse to avoid accountability.
N
nightdancer19 Jul 2016 20:47Alternative approach: hire a new soil expert with the updated information and then proceed from there. Simply digging as the civil engineer suggests – never ever.
Uwe82 schrieb:
If they communicate and agree on a procedure, the excavation is done, and then the geotechnical engineer officially approves the pit in writing, you are legally protected as much as possible. Just talking won’t help, that’s true, because then everyone could just blame someone else. Someone has to take responsibility, and that only works if that person has approved it on-site, otherwise they can always deny responsibility. The problem here is that the geotechnical engineer will not approve the "hole." As already said, NO ONE wants to take responsibility for anything. The only reasonable solution now (and probably the cheapest) is to replace the soil according to the structural engineer’s recommendation. Instead of spending money now on new calculations and such, put the money into replacing the soil. Instead of €2000 for new calculations, spend €2000 on topping up with fill material. That’s it. It costs the same but achieves more than necessary. In my opinion, recalculating is pointless and most likely won’t make things cheaper.
What kind of requirements are there for the fill material?
Payday schrieb:
The problem here is just that the geotechnical engineer will not approve the "hole." You are really extremely pessimistic. As I already mentioned above, the geotechnical engineer handled it the same way for us and gave us written approval. In our case, it involved a steeper slope than what had been approved in the municipality’s geotechnical report beforehand. A laboratory test was conducted, and the approval was made together with both site managers and the civil engineer. If the stability had been insufficient, we would have had to install shoring.
Additionally, it was decided whether the soil (due to the hillside location) at the front of the slope was already load-bearing enough or if soil replacement was necessary.
So, it’s nonsense that no one ever does this and that everyone always tries to avoid responsibility. Talking to the people involved usually brings the best solutions.