Hello everyone!
This is my first post since we started planning to become homeowners.
It’s about the cost estimation—specifically for our earthworks. Here’s what we know about the plot:
- It is 374 sqm (4029 sq ft) in size
- The house has external dimensions of 9.27 m x 11.07 m (30.4 ft x 36.3 ft) and will be built without a basement on a concrete slab
- A garage and a parking space in front of it are planned
- Currently, there is a height difference of 1.30 m (4.3 ft) between the ground level and the underside of the slab, so about 90 cm (35 in) to the bottom edge of the slab
- Our builder will supply 40 cm (16 in) of capillary-breaking material for backfilling (free of charge or included in the house price)
- According to the soil report for the building site (attached, starting on page 33 Baufeld WA 4a*), an average of 40 cm (16 in) of topsoil has to be excavated
- If I understand the above report correctly, no soil replacement is necessary
I wanted to ask for a realistic estimate of the costs involved (excluding utility connections, which I will calculate separately). We are currently estimating around 30,000 euros. Online, I find anywhere between 5,000 and 80,000 euros, which doesn’t really help. The soil conditions are probably not ideal due to the significant amount of fill material.
Looking forward to your advice, and thanks in advance to everyone involved!
This is my first post since we started planning to become homeowners.
It’s about the cost estimation—specifically for our earthworks. Here’s what we know about the plot:
- It is 374 sqm (4029 sq ft) in size
- The house has external dimensions of 9.27 m x 11.07 m (30.4 ft x 36.3 ft) and will be built without a basement on a concrete slab
- A garage and a parking space in front of it are planned
- Currently, there is a height difference of 1.30 m (4.3 ft) between the ground level and the underside of the slab, so about 90 cm (35 in) to the bottom edge of the slab
- Our builder will supply 40 cm (16 in) of capillary-breaking material for backfilling (free of charge or included in the house price)
- According to the soil report for the building site (attached, starting on page 33 Baufeld WA 4a*), an average of 40 cm (16 in) of topsoil has to be excavated
- If I understand the above report correctly, no soil replacement is necessary
I wanted to ask for a realistic estimate of the costs involved (excluding utility connections, which I will calculate separately). We are currently estimating around 30,000 euros. Online, I find anywhere between 5,000 and 80,000 euros, which doesn’t really help. The soil conditions are probably not ideal due to the significant amount of fill material.
Looking forward to your advice, and thanks in advance to everyone involved!
P
Pinkiponk14 Mar 2022 11:49Hafenstraße schrieb:
5th QUESTION: What costs does a geotextile cause? For us, postal code 0457x, it was "Geotextile delivered and installed on site 128.62 m2 (1384 sq ft) at €2.45 each." What you wrote sounds similar to the work that was done for us. In an earlier post, I already listed some items with prices; as soon as our second (and last?) invoice arrives, I will share the remaining items. --> Our house measures 9.40 m x 9.40 m (31 ft x 31 ft), and the slab has an overhang around it, but I don’t recall the exact size.
The slab was included in our house price, but we placed additional orders for the following (not all may be necessary for you, see *):
1x MSH up to 6 m (20 ft) total length installed in the foundation slab (including earthworks) €1,120.00
5x drainage connections according to plan, additionally €192.00 each
3 linear meters (lfm) of empty pipes DN 100, including earthworks, €96.00 each
1x *cleaning of the concrete pump at the factory €235.00
1x **delivery of an MSH up to 6 m (20 ft) total length €1,695.00
Total including VAT €4,298.00
* This could, if desired, also be done on the plot itself, for example where a concrete floor for a carport, garage, or garden shed is planned anyway. Then this item wouldn’t be needed. I don’t know how simple this would be in practice. Maybe another forum member has done it this way and can share their experience here.
** The MSH can also be ordered yourself (possibly cheaper?) “online” and brought to the plot. We decided against this for various reasons, but the slab contractor offered it. Maybe you don’t have an MSH either.
Hafenstraße schrieb:
Or can I put this concern aside for now? Do that. I’m confident, and worrying won’t help you anyway.
Hafenstraße schrieb:
Wishing you a great start to the week! Thanks, you too.
S
Stefan00114 Mar 2022 12:16Who is responsible for the structural engineering?
The foundation must be considered within the scope of the structural engineering. Whether a slab-on-grade is load-bearing depends on the house to be built.
It is best to include the soil investigation report as part of the contract, or at least get a written confirmation that the construction will be carried out according to the report for the specific house.
In my opinion, the building company should also provide guidelines on how the foundation should be constructed.
How deep the soil needs to be replaced ultimately depends on the house and the slab foundation.
The foundation must be considered within the scope of the structural engineering. Whether a slab-on-grade is load-bearing depends on the house to be built.
It is best to include the soil investigation report as part of the contract, or at least get a written confirmation that the construction will be carried out according to the report for the specific house.
In my opinion, the building company should also provide guidelines on how the foundation should be constructed.
How deep the soil needs to be replaced ultimately depends on the house and the slab foundation.
From my perspective, there are no signs or concerns in your case that this will turn into a financial disaster.
On the contrary, your situation mainly involves lower costs for fill material rather than disposal costs plus additional backfilling, which is often the case.
With the planned budget of 30,000 EUR, you should be well covered if nothing unexpected happens 🙂
Very roughly, as a worst-case estimate based on your information:
1. Disposal of 80 cm (31 inches) over 120 m² (1,292 sq ft) = 100 m³ (3,531 ft³) = maximum approx. 4,000 EUR
2. Backfilling of 170 cm (67 inches) over 120 m² (1,292 sq ft) = 204 m³ (7,205 ft³) = maximum approx. 8,500 EUR
3. Backfilling of 130 cm (51 inches) over 255 m² (2,744 sq ft) = 330 m³ (11,654 ft³) = maximum approx. 13,500 EUR
+ Survey (max. 1,500 EUR) + site setup (500 EUR) + fine grading (500 EUR) + compaction tests (400 EUR) + drainage / piping ...
So, rather a worst-case scenario and very approximate, but I think 30,000–35,000 EUR should be sufficient. Probably less.
On the contrary, your situation mainly involves lower costs for fill material rather than disposal costs plus additional backfilling, which is often the case.
With the planned budget of 30,000 EUR, you should be well covered if nothing unexpected happens 🙂
Very roughly, as a worst-case estimate based on your information:
1. Disposal of 80 cm (31 inches) over 120 m² (1,292 sq ft) = 100 m³ (3,531 ft³) = maximum approx. 4,000 EUR
2. Backfilling of 170 cm (67 inches) over 120 m² (1,292 sq ft) = 204 m³ (7,205 ft³) = maximum approx. 8,500 EUR
3. Backfilling of 130 cm (51 inches) over 255 m² (2,744 sq ft) = 330 m³ (11,654 ft³) = maximum approx. 13,500 EUR
+ Survey (max. 1,500 EUR) + site setup (500 EUR) + fine grading (500 EUR) + compaction tests (400 EUR) + drainage / piping ...
So, rather a worst-case scenario and very approximate, but I think 30,000–35,000 EUR should be sufficient. Probably less.
H
Hafenstraße14 Mar 2022 13:03Understood. In the meantime, I also looked up the issue with the geotextile. It doesn’t seem to be a big deal! Thanks, Pinkiponk! Our house will be slightly larger, and we are also having the foundation slab installed by the manufacturer (knowing that this will cost a few hundred euros more than if we outsourced it). But we simply don’t have enough knowledge or confidence to procure such a fundamental component ourselves and coordinate between the companies. The MSH (wall insulation system) is included. As far as I understand correctly, this is standard with mid-range providers nowadays and can no longer be opted out of. Likewise, our manufacturer will handle part of the earthworks according to the scope of work, namely the excavation, construction, and backfilling for the frost protection edge insulation down to 80cm (31 inches) depth. I can’t quite imagine how this will work exactly. After all, “80cm depth” at the moment, due to the planned fill, is about 10–20cm (4–8 inches) above our current ground level. But I’m sure others will give that some thought... (I hope so...)
Putting worries aside is incredibly difficult for me. Surely many people feel the same. Currently, we feel more than deceived by the site manager of the house manufacturer, with whom we already created a detailed calculation weeks ago. Surveyor, building permit / planning permission, geotechnical report... everything costs at least 1,500 euros more than calculated. For example, the building permit was estimated at 500 euros, and we repeatedly made it clear that we don’t have more money than budgeted in total. What happened last week? A look at the fee schedule of the city of Duisburg shows that the permit will actually cost 1,500 euros. The surveyor also follows the official fee schedule and wants 5,500 euros instead of the calculated 3,000 euros. Every day, we are completely shocked. And now here comes the big chunk for site preparation. If costs here also exceed the estimate by 50–100% (around 30,000 euros), we will be bankrupt before the topping-out ceremony. No one expects an exact calculation down to the last cent. But that also means sometimes things are charged a bit higher than they eventually come to. After all, you trust the architects, house salespeople, and site managers. What other choice does a construction layperson have, and why shouldn’t you? I don’t question every other service I’m not professionally involved in. For us, so far, everything is over budget, which is completely killing our excitement, pride, and literally our sleep.
Back to the topic: The structural engineering is also done by the house manufacturer. Basically, they build the house completely once the ground is prepared (by us). We have already signed the contract (to lock in the fixed price, but we are still in the cancellation period). The bank follows the day after tomorrow, and in April the notary for the land. So there’s no turning back on the contracts anymore.
Netuser, your response is very helpful to me, too. From my point of view, it’s good to have a concrete number, as concrete as can be estimated. Thanks! You are calculating on the high side, though I believe it will tend to be expensive for us as well. We are building near a water protection area, so only Z0 natural gravel can be used, no RCL or anything like that. But as mentioned, if we meet this budget, there will be champagne corks popping. Supposedly, our site manager has contact with an excavation contractor who supplies, installs, and compacts gravel for 22 euros net per m³ (cubic meter). You are estimating more than 40 euros per m³. Based on experience, you will probably be right!
Putting worries aside is incredibly difficult for me. Surely many people feel the same. Currently, we feel more than deceived by the site manager of the house manufacturer, with whom we already created a detailed calculation weeks ago. Surveyor, building permit / planning permission, geotechnical report... everything costs at least 1,500 euros more than calculated. For example, the building permit was estimated at 500 euros, and we repeatedly made it clear that we don’t have more money than budgeted in total. What happened last week? A look at the fee schedule of the city of Duisburg shows that the permit will actually cost 1,500 euros. The surveyor also follows the official fee schedule and wants 5,500 euros instead of the calculated 3,000 euros. Every day, we are completely shocked. And now here comes the big chunk for site preparation. If costs here also exceed the estimate by 50–100% (around 30,000 euros), we will be bankrupt before the topping-out ceremony. No one expects an exact calculation down to the last cent. But that also means sometimes things are charged a bit higher than they eventually come to. After all, you trust the architects, house salespeople, and site managers. What other choice does a construction layperson have, and why shouldn’t you? I don’t question every other service I’m not professionally involved in. For us, so far, everything is over budget, which is completely killing our excitement, pride, and literally our sleep.
Back to the topic: The structural engineering is also done by the house manufacturer. Basically, they build the house completely once the ground is prepared (by us). We have already signed the contract (to lock in the fixed price, but we are still in the cancellation period). The bank follows the day after tomorrow, and in April the notary for the land. So there’s no turning back on the contracts anymore.
Netuser, your response is very helpful to me, too. From my point of view, it’s good to have a concrete number, as concrete as can be estimated. Thanks! You are calculating on the high side, though I believe it will tend to be expensive for us as well. We are building near a water protection area, so only Z0 natural gravel can be used, no RCL or anything like that. But as mentioned, if we meet this budget, there will be champagne corks popping. Supposedly, our site manager has contact with an excavation contractor who supplies, installs, and compacts gravel for 22 euros net per m³ (cubic meter). You are estimating more than 40 euros per m³. Based on experience, you will probably be right!
S
Stefan00114 Mar 2022 13:19Hafenstraße schrieb:
Our manufacturer also handles part of the earthworks according to the scope of work, specifically the excavation, construction, and backfilling of the frost skirts up to a depth of 80cm (31 inches). I can’t quite picture how this will actually work because the "80 cm depth" at the moment, due to the fill that still needs to be added, is about 10-20cm (4-8 inches) ABOVE our current ground level. But I’m sure others will have different thoughts on this... (I hope...) Lesson 1: Nobody takes responsibility!
If you get the feeling that something is unplanned or hasn’t been coordinated, that’s usually the case.
Always ask questions and insist on clarification!
Even if your site manager builds 100 houses a year, there will always be things that were not planned or agreed upon. You are truly the only person you can rely on during the build.
And no one else will give it a second thought!
In our case, the earthworks were carried out by the general contractor as required by the site conditions (and based on reports and structural calculations). This has the big advantage that, in case of any warranty issues, there is a single responsible party.
(Unfortunately, this was a financial disaster for us, but that’s a different story.)
You should definitely clarify who is responsible for tasks outside the scope of work, whether they will provide a change order quote, or if you need/can/may prepare the site accordingly yourself.
Hafenstraße schrieb:
Our manufacturer also takes on part of the earthworks according to the construction service description, specifically the excavation, installation, and backfilling for the frost skirts down to 80 cm (31 inches) depth. I honestly can’t quite picture how this will work in detail. After all, because of the planned fill, the "80 cm (31 inches) depth" is currently about 10-20 cm (4-8 inches) above our ground level. But surely others will consider that... (I hope...) First, the area up to the slab level is filled, compacted, and fine-graded.
Then your builder or their excavators dig out the 80 cm (31 inches) again and temporarily place the soil to the side.
Hafenstraße schrieb:
Surveyors, building permits / planning permission, soil reports... everything ends up costing at least 1,500 Euro more than estimated. For example, for the building permit / planning permission: we budgeted 500 Euro, we made it very clear multiple times that we don’t have much more money than the total sum estimated, and what happened last week? A look at the fee schedule of the city of Duisburg reveals: the permit will cost 1,500 Euro. The surveyor also works according to the fee schedule and wants 5,500 Euro instead of the estimated 3,000 Euro. There’s not much you can do about the city’s fee schedule.
I don’t believe a soil report would cost that much more, and the surveyor shouldn’t be that expensive either...
1. Comparing quotes is definitely worthwhile.
2. Ask the surveyor if an official site plan (“amtlicher Lageplan”) was offered or required! This is often NOT necessary but can be offered and is much more expensive.
I’m practically in your neighborhood and can recommend a very competent and reasonably priced surveyor from the region.
Hafenstraße schrieb:
Supposedly, our site manager has contact with a civil engineer who supplies, installs, and compacts gravel for 22 Euros net per m3. You’re calculating over 40 Euros per m3. Based on experience, you’re probably right! A side note: When comparing offers from civil engineers, pay attention to the units used! Some quote in tons, others in cubic meters, or a mix... This can lead to misunderstandings or “pitfalls.”
Your mentioned 22 EUR sounds reasonable/affordable. So I basically accounted for a “worst case” but think that for the fill, the mixed calculation cost should be (significantly) lower.
By the way: How is the rainwater drainage handled? Into the sewer system or on-site (plus infiltration trench)?
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