Hello dear forum,
After much consideration, we have finally decided on a house.
It will be 175 sqm (1,884 sq ft) for a family of five.
We are still debating: basement or slab-on-grade?
We have a slightly sloped plot and are weighing which option would be the best in the end. The basement would be a utility basement, incorporating a double garage, a workshop, and a storage room.
The alternative would be to build on a slab-on-grade with a double garage plus storage/shed space.
Since we are building on a slight slope, we are thinking about what costs to expect for each option. Of course, excavation costs are hard to predict, but maybe someone can estimate. Two excavation contractors have already examined the site and said that both basement and slab-on-grade are possible without problems. However, no one wants to give us a rough cost estimate, which complicates things.
Our idea was that with the basement including two garages, we might save some costs for slope retaining. Building on a slab, plus a double garage, plus higher costs for slope retaining might end up in a similar price range. We wouldn’t have much storage space inside the house.
The quotes we have are as follows:
Slab-on-grade 17,000 + 25,000 for double garage including foundation + total X for excavation work.
Basement 45,000 + 20,000 for finishing + total X for excavation work.
Could anyone give an assessment of which option seems more sensible?
After much consideration, we have finally decided on a house.
It will be 175 sqm (1,884 sq ft) for a family of five.
We are still debating: basement or slab-on-grade?
We have a slightly sloped plot and are weighing which option would be the best in the end. The basement would be a utility basement, incorporating a double garage, a workshop, and a storage room.
The alternative would be to build on a slab-on-grade with a double garage plus storage/shed space.
Since we are building on a slight slope, we are thinking about what costs to expect for each option. Of course, excavation costs are hard to predict, but maybe someone can estimate. Two excavation contractors have already examined the site and said that both basement and slab-on-grade are possible without problems. However, no one wants to give us a rough cost estimate, which complicates things.
Our idea was that with the basement including two garages, we might save some costs for slope retaining. Building on a slab, plus a double garage, plus higher costs for slope retaining might end up in a similar price range. We wouldn’t have much storage space inside the house.
The quotes we have are as follows:
Slab-on-grade 17,000 + 25,000 for double garage including foundation + total X for excavation work.
Basement 45,000 + 20,000 for finishing + total X for excavation work.
Could anyone give an assessment of which option seems more sensible?
icandoit schrieb:
Please allow me to disagree with you, even though I share your opinion. The excavation for the basement requires more sloping than the foundation slab, right? I would allow that, but you are by no means sharing my opinion and are talking about something completely different: the basement itself does not require sloping, the construction of the basement requires working space (which is temporary and therefore does not need to permanently occupy space on the site).
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
11ant schrieb:
I would allow that, but you are by no means sharing my opinion and are talking about something completely different: the basement does not require sloping; the basement construction requires working space (but that space is temporary and therefore does not need to be permanently available on the property).I am an advocate of building with a basement. So, I share your opinion.icandoit schrieb:
I am an advocate for building with a basement. Therefore, I agree with you. However, that is not the same, as I am not an advocate for basements. I simply reject the idea of spending the same amount of money to "forgo" a basement as it would cost to build one. So if the property won’t prevent you from including a basement in the budget, then it should at least be provided so that it can be put to use.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
I’m revisiting this topic since we plan to start building soon and have received several quotes over the past three weeks. This might be helpful if you are currently considering a basement.
Of course, costs depend heavily on the ground conditions, the extent of waterproofing and insulation, and the desired wall thickness. Additional extras like pre-installed electrical wiring and other features naturally come at an extra cost.
We requested quotes from major providers: Dennert, Südwest, Glatthaar, Knecht, Bürkle, MB-Keller. For a 10 x 10 meter (33 x 33 feet) footprint and waterproofing against occasional groundwater pressure, the range was from €46,000 to €80,000. This excludes heating, floor finishes, and earthworks.
At €46,000, the waterproofing was insufficient, and there was no staircase, light wells, floor slab insulation, or drainage membrane included.
At €80,000, the offer included waterproofing against groundwater pressure, factory-installed 16 cm (6 inch) core insulation of the basement walls to KfW 55 standard (wall U-value of 0.19 W/m²K), as well as 200 mm (8 inch) load-bearing perimeter insulation in double layers beneath the floor slab, plus staircase, light wells, drainage membrane, and more. For a finished living basement, ventilation, heating, and wall and floor finishes are still needed.
On Südwest Keller’s website, there are three sample offers which align with these numbers to some extent. As mentioned, waterproofing based on ground conditions and thermal insulation are the main cost drivers.
Of course, costs depend heavily on the ground conditions, the extent of waterproofing and insulation, and the desired wall thickness. Additional extras like pre-installed electrical wiring and other features naturally come at an extra cost.
We requested quotes from major providers: Dennert, Südwest, Glatthaar, Knecht, Bürkle, MB-Keller. For a 10 x 10 meter (33 x 33 feet) footprint and waterproofing against occasional groundwater pressure, the range was from €46,000 to €80,000. This excludes heating, floor finishes, and earthworks.
At €46,000, the waterproofing was insufficient, and there was no staircase, light wells, floor slab insulation, or drainage membrane included.
At €80,000, the offer included waterproofing against groundwater pressure, factory-installed 16 cm (6 inch) core insulation of the basement walls to KfW 55 standard (wall U-value of 0.19 W/m²K), as well as 200 mm (8 inch) load-bearing perimeter insulation in double layers beneath the floor slab, plus staircase, light wells, drainage membrane, and more. For a finished living basement, ventilation, heating, and wall and floor finishes are still needed.
On Südwest Keller’s website, there are three sample offers which align with these numbers to some extent. As mentioned, waterproofing based on ground conditions and thermal insulation are the main cost drivers.
J
JoachimG.10 Jan 2021 15:12I'm quite curious now. Due to the 11ants basement rule, we have also completely revised our plans and now want to design with a basement (just over 2 meters (6.5 feet) slope over an 11 meter (36 feet) depth). The designer we consulted basically confirmed the rule for us. @Amel_NRW, was Dennert (they are located quite close to us) reasonable in terms of pricing? Because we are still at the stage of getting quotes.
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