Hello everyone,
We are currently planning our house, and according to the soil report, it looks like we will need a well foundation. Initial research shows this could add at least €10,000 (around $11,000) in additional costs.
Has anyone had experience with this? Especially the pricing would be interesting.
We plan for a 120 m² (1,290 sq ft) footprint plus 60 m² (645 sq ft). For the garage, we have a quote of €15,000 (about $16,500) for the related concrete slab and another €15,000 for the garage itself (excluding the door).
According to the report, a slab foundation would be possible if we include a basement. Now I’m considering possibly building a basement to avoid the well foundation.
The idea is, instead of paying €30,000 (around $33,000) for the garage plus at least €10,000 for the well foundation, to invest the money in a basement. I have requested a quote for that and expect it early next week. But I wanted to ask here beforehand if this is a completely dumb idea.
Good luck and thanks in advance!
We are currently planning our house, and according to the soil report, it looks like we will need a well foundation. Initial research shows this could add at least €10,000 (around $11,000) in additional costs.
Has anyone had experience with this? Especially the pricing would be interesting.
We plan for a 120 m² (1,290 sq ft) footprint plus 60 m² (645 sq ft). For the garage, we have a quote of €15,000 (about $16,500) for the related concrete slab and another €15,000 for the garage itself (excluding the door).
According to the report, a slab foundation would be possible if we include a basement. Now I’m considering possibly building a basement to avoid the well foundation.
The idea is, instead of paying €30,000 (around $33,000) for the garage plus at least €10,000 for the well foundation, to invest the money in a basement. I have requested a quote for that and expect it early next week. But I wanted to ask here beforehand if this is a completely dumb idea.
Good luck and thanks in advance!
W
WilderSueden14 Feb 2023 08:48I don't quite understand that either. It makes sense to carry out the soil survey as soon as you know where the house will be located, but before completing a lot of other planning work (such as structural calculations) that may become obsolete due to the soil survey.
Basically, you can still move the house even after the soil survey. If the soil conditions are uniform throughout, this is not a problem. If the soil varies significantly, you will likely face surprises anyway, since the survey is usually conducted only at the four corners.
Basically, you can still move the house even after the soil survey. If the soil conditions are uniform throughout, this is not a problem. If the soil varies significantly, you will likely face surprises anyway, since the survey is usually conducted only at the four corners.
Ok, the issue is clearer to me now. The water channel running through the middle of the property causes not only moisture in the soil but also different ground conditions in the area of the new construction.
I strongly recommend having a new expert report done. I would also suggest not necessarily choosing the cheapest option.
I’m thinking about how I would approach this...
Regarding the costs:
Given the circumstances, I believe a basement could easily reach around €100,000 (approx. $110,000).
- Excavation
- Dewatering
- Possibly shoring
- Foundation as a "grey tank" (watertight concrete structure)
A foundation using well rings or piles is definitely more affordable. I would also suggest considering vibro-compaction columns (a method I favor).
The most expensive item among these options is definitely the site setup. Unfortunately, I can’t provide exact prices since things have changed recently and it depends on many factors. But €30,000 (approx. $33,000) for piles is realistic. Well rings are generally somewhat cheaper, as are vibro-compaction columns.
I also still see the possibility of a shallow foundation combined with a hillside drainage system that "dries out" the water channel or diverts it around the house.
Get another expert report done, ideally including possible foundation heights (top edge of the finished floor level), so the building waterproofing can be precisely determined. That’s where the next thousands will be lost.
I strongly recommend having a new expert report done. I would also suggest not necessarily choosing the cheapest option.
I’m thinking about how I would approach this...
Regarding the costs:
Given the circumstances, I believe a basement could easily reach around €100,000 (approx. $110,000).
- Excavation
- Dewatering
- Possibly shoring
- Foundation as a "grey tank" (watertight concrete structure)
A foundation using well rings or piles is definitely more affordable. I would also suggest considering vibro-compaction columns (a method I favor).
The most expensive item among these options is definitely the site setup. Unfortunately, I can’t provide exact prices since things have changed recently and it depends on many factors. But €30,000 (approx. $33,000) for piles is realistic. Well rings are generally somewhat cheaper, as are vibro-compaction columns.
I also still see the possibility of a shallow foundation combined with a hillside drainage system that "dries out" the water channel or diverts it around the house.
Get another expert report done, ideally including possible foundation heights (top edge of the finished floor level), so the building waterproofing can be precisely determined. That’s where the next thousands will be lost.
L
Lukas_Sch14 Feb 2023 11:13We have 16 piles for a concrete slab measuring 9.5m by 9.5m (31ft by 31ft). The cost was €36,000 in 2022. A lot of money for two days of excavator work.
Good luck
Good luck
N
Narnulf136814 Feb 2023 11:59Cronos86 schrieb:
Okay, the issue is clearer to me now. The water channel that runs through the middle of the plot not only causes water in the soil but also results in different soil conditions in the area of the new construction.
I strongly recommend having a new report done. I wouldn’t necessarily go for the cheapest option.
I’m thinking about how I would approach this...
Regarding the costs:
Given the circumstances, I think a basement could easily cost around €100,000 (about $110,000).
- Excavation
- Water management
- Possible shoring
- Foundation as a "watertight concrete box" (“gray tank”)
A foundation using caisson rings or piles is definitely cheaper. I also suggest considering vibro-compaction columns, which I’m a fan of.
The most expensive item in these options is definitely the site setup. Unfortunately, I can’t give you exact prices because a lot has changed lately and it depends on many factors. But the €30,000 (about $33,000) quoted for piles is realistic. Caisson rings are generally somewhat less expensive, as are vibro-compaction columns.
I still see the option of a shallow foundation combined with a hillside drainage system that “dries out” the water channel or directs it around the house.
Have another report done, ideally including possible foundation height levels (top edge of finished floor), so the building waterproofing can be accurately determined. That’s where you will lose the next few thousand euros. Thank you for your detailed reply!
I understood from the construction company that the structural calculations and load cases are only performed once the building permit / planning permission is granted, to avoid duplicate work. For that, they then require a geotechnical report.
The surveyor who carried out the report (2019) said he could only give a specific foundation recommendation after the load case is known, which seems like a catch-22.
Maybe I misunderstood something. I will call the surveyor again today and get an offer.
I had assumed the report was older since outdated standards were used.
Of course, the report can still be used. I simply do not consider the report to be of good quality and believe that an assessment by another expert might provide better recommendations.
What immediately caught my attention:
- Building waterproofing according to standard 18195 was replaced in 2017 by 18533-1
- Homogeneous zones are missing (they replace soil classes)
- Use of excavated soil without declaration analysis (no landfill will accept this)
- No description of the foundation, no soil bearing pressures or bearing resistances, etc.
Of course, the report can still be used. I simply do not consider the report to be of good quality and believe that an assessment by another expert might provide better recommendations.
What immediately caught my attention:
- Building waterproofing according to standard 18195 was replaced in 2017 by 18533-1
- Homogeneous zones are missing (they replace soil classes)
- Use of excavated soil without declaration analysis (no landfill will accept this)
- No description of the foundation, no soil bearing pressures or bearing resistances, etc.
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