ᐅ How much additional cost is expected based on the structural engineer’s calculations?
Created on: 11 Jun 2023 11:17
L
Lauralila88
Hello,
I have to admit that we approached the house construction quite naively...
We have already signed the detailed construction plans, and now the construction company wants us to waive our right to special termination in writing – is that even legal?
Now to the main question: we signed a fixed price contract (turnkey), but the site manager said that the price might change again after the structural engineer's calculations???? I mean, we won’t make any more changes to the plans, and we have already budgeted with the bank based on the known price – is this normal? It feels like buying a pig in a poke!
Best regards
I have to admit that we approached the house construction quite naively...
We have already signed the detailed construction plans, and now the construction company wants us to waive our right to special termination in writing – is that even legal?
Now to the main question: we signed a fixed price contract (turnkey), but the site manager said that the price might change again after the structural engineer's calculations???? I mean, we won’t make any more changes to the plans, and we have already budgeted with the bank based on the known price – is this normal? It feels like buying a pig in a poke!
Best regards
Lauralila88 schrieb:
I submitted an inquiry nearby, and they said around 20,000 eurosThe problem is that although the weight of the excavated soil does not change, the volume, which is used for billing, triples during excavation.
Well, it says excavation, removal, and backfilling.
The issue of volume versus weight depends on the service provider. In my case, it was only charged by weight, but I could have also been billed by volume. However, the civil engineer advised against that for exactly the reason you mention, @ypg...
The issue of volume versus weight depends on the service provider. In my case, it was only charged by weight, but I could have also been billed by volume. However, the civil engineer advised against that for exactly the reason you mention, @ypg...
Lauralila88 schrieb:
I asked nearby and they quoted about 20,000 eurosHere are prices (net) from the end of 2021:
Removal of topsoil 250 sqm (2691 sqft), lateral storage: €375.00
Excavation, loosening, loading, 540 cubic meters: €3,456.00
Disposal of excavated material (uncontaminated) 1,735 tons: €15,528.97
If it concerns earthworks in general, you should also consider compaction of the foundation soil, delivery and installation of frost protection layers and backfilling with supplied material, possibly recycling for the site access road, rainwater and sewage piping, multiple utility connections or other house penetrations, potential drainage, geotextile/membrane systems, and so on.
Tolentino schrieb:
Whether volume or weight is used depends on the service provider. In my case, it was charged by weight only, but I could have also chosen to be charged by volume. However, the excavation contractor advised against it, exactly for the reason you mentioned, @ypg... In this case (#173), companies are most likely asked for the excavation volume in cubic meters (basement) before the actual volume is known.
Hello,
Here are my brief comments on this extensive topic, especially since there has been a lot of discussion about waterproofing and soil excavation.
Bitumen coating + dimpled membrane (waterproofing against ground moisture, load case assessment according to DIN 18533-1:2017-07, W1.1-E)
Waterproofing according to W1.1-E can only be applied in the absence of groundwater and on well-draining soils (sand/gravel).
W1.2-E involves using additional drainage even with impermeable soils but without groundwater. (Here, the challenge is the long-term functionality of the drainage over decades and the approval process).
Black or white tank systems must be used with hydrostatic pressure (groundwater/floodwater, W2.1-E).
A black tank system, as commonly described online, consists of a thick-bitumen coating created by welding bitumen sheets. This is of course different from applying two coats of bitumen paint.
A white tank system is watertight concrete (WU concrete). Nowadays, a "grey tank" system is commonly used instead (with additional joint and connection sealing on the outside).
To assess the load case for the structure, you naturally need the soil report.
The real challenge, as already mentioned, is the seismic zone and the resulting requirements for basement structural engineering. In my experience, this almost always requires a concrete structure.
When it comes to soil excavation, I would advise staying calm at first. Once you have a schedule, have soil samples taken (analyses are only valid for six months). From August 1, 2023, the Substitute Materials Ordinance (EBV) comes into effect, which changes some things, but many core aspects remain the same. If you have an excavation contractor, have them inform you where they plan to bring the material and what analysis they require. Most disposal and backfilling sites still apply their old acceptance criteria (LAGA/landfill regulations/backfilling guidelines, etc.). This way, you can avoid duplicate analysis costs or time pressure during excavation (analysis can take up to two weeks).
Best regards
Here are my brief comments on this extensive topic, especially since there has been a lot of discussion about waterproofing and soil excavation.
Bitumen coating + dimpled membrane (waterproofing against ground moisture, load case assessment according to DIN 18533-1:2017-07, W1.1-E)
Waterproofing according to W1.1-E can only be applied in the absence of groundwater and on well-draining soils (sand/gravel).
W1.2-E involves using additional drainage even with impermeable soils but without groundwater. (Here, the challenge is the long-term functionality of the drainage over decades and the approval process).
Black or white tank systems must be used with hydrostatic pressure (groundwater/floodwater, W2.1-E).
A black tank system, as commonly described online, consists of a thick-bitumen coating created by welding bitumen sheets. This is of course different from applying two coats of bitumen paint.
A white tank system is watertight concrete (WU concrete). Nowadays, a "grey tank" system is commonly used instead (with additional joint and connection sealing on the outside).
To assess the load case for the structure, you naturally need the soil report.
The real challenge, as already mentioned, is the seismic zone and the resulting requirements for basement structural engineering. In my experience, this almost always requires a concrete structure.
When it comes to soil excavation, I would advise staying calm at first. Once you have a schedule, have soil samples taken (analyses are only valid for six months). From August 1, 2023, the Substitute Materials Ordinance (EBV) comes into effect, which changes some things, but many core aspects remain the same. If you have an excavation contractor, have them inform you where they plan to bring the material and what analysis they require. Most disposal and backfilling sites still apply their old acceptance criteria (LAGA/landfill regulations/backfilling guidelines, etc.). This way, you can avoid duplicate analysis costs or time pressure during excavation (analysis can take up to two weeks).
Best regards
Harakiri schrieb:
Here are the prices (net, excluding VAT) from the end of 2021:
Removal of topsoil, 250 sqm (2690 sq ft), lateral storage: €375.00
Excavation, loosening, loading, 540 m³ (711 cu yd): €3,456.00
Disposal of excavated material (uncontaminated), 1,735 t (1,914 tons): €15,528.97
540 m³ (711 cu yd) is quite a substantial volume for a house project, right? I am puzzled as to how 540 m³ (711 cu yd) translates into 1,735 t (1,914 tons). That implies a density of about 3.2 tonnes per m³ (2.9 tons per cu yd). Clay soil typically has a density around 1.65 to 1.8 t/m³ (1.5 to 1.6 tons per cu yd).
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