Hello Forum,
We are currently planning a basement for our single-family home. In addition to the building services room and a laundry room (washing machine + dryer), there will also be a gym and a study.
The four rooms will cover an area of about 65sqm (700 sq ft). The ground is suitable for this (from approximately 2.5m (8 feet) of medium-density gravel layer according to soil report – load class 2 according to waterproof concrete guidelines). The basement will have perimeter insulation (exterior walls, floor slab, basement ceiling) – the design is currently based on KfW 40 standards, which require thicker insulation according to advice from the forum 😉 The study and gym will have underfloor heating. The study will also have a light well. The gym and laundry room will have light shafts. The building services room will have no windows. The floor will be continuously laid with anhydrite screed, followed by a floor covering. Electrical installations will be surface-mounted on the walls.
The additional construction costs (especially setting out the building grid and excavation of the foundation pit) are not included in the costs. I am currently budgeting about €1250 per sqm (approximately $130 per sq ft), which is about €81,000 for the basement. However, everyone looks at this price as if it were a car and says that €35,000 more than enough? What is your assessment?
Best regards,
Andy
We are currently planning a basement for our single-family home. In addition to the building services room and a laundry room (washing machine + dryer), there will also be a gym and a study.
The four rooms will cover an area of about 65sqm (700 sq ft). The ground is suitable for this (from approximately 2.5m (8 feet) of medium-density gravel layer according to soil report – load class 2 according to waterproof concrete guidelines). The basement will have perimeter insulation (exterior walls, floor slab, basement ceiling) – the design is currently based on KfW 40 standards, which require thicker insulation according to advice from the forum 😉 The study and gym will have underfloor heating. The study will also have a light well. The gym and laundry room will have light shafts. The building services room will have no windows. The floor will be continuously laid with anhydrite screed, followed by a floor covering. Electrical installations will be surface-mounted on the walls.
The additional construction costs (especially setting out the building grid and excavation of the foundation pit) are not included in the costs. I am currently budgeting about €1250 per sqm (approximately $130 per sq ft), which is about €81,000 for the basement. However, everyone looks at this price as if it were a car and says that €35,000 more than enough? What is your assessment?
Best regards,
Andy
Andi3579 schrieb:
That, of course, brings a whole set of different challenges. I’m curious how others have solved the second escape route? Is there a separate basement staircase here? Either that. Or since you’re planning a light well anyway: a sufficiently large window and climbing aids like handles, steps, etc.
Andi3579 schrieb:
I have a cross-trainer, a treadmill, a power rack, a cable tower, and free weights. That should last me for the next 30 years—even with lower ceiling height 😉 I have 220 cm (87 inches) ceiling height in the basement, and overhead presses standing up, or snatches and jerks with the barbell, just don’t work anymore. Those extra 20 cm (8 inches) make a huge difference.
Maybe I can help you with some current figures: the shell construction costs for our waterproof concrete basement, approximately 145 sqm (1,560 sq ft) in area, with a structural height between 2.69 and 2.82 m (8.8 and 9.25 ft) depending on the section. Walls are precast elements, ceiling is a combination of filigree slabs and cast-in-place concrete, including insulation of 14 cm (5.5 inches) — although not fully applied, as part of the area is an uninsulated garage and another part is an open basement section, meaning the insulation there will be added later. It includes 2 light shafts and 2 windows, plus factory preparation for electrical installation (flush-mounted boxes and empty conduits embedded in the concrete). The total is about 106,000 euros.
Our foundation is somewhat special in parts (strip footing plus frost protection skirts on the exposed sides) and we have a ceiling drop — both of which are quite expensive. Therefore, a simple slab foundation with all wall surfaces insulated would probably end up costing roughly the same in the end.
This means, for the shell construction alone, excluding groundwork or interior finishing, you can expect around €750 (about $820) per sqm (approximately $76 per sq ft), though prices may be somewhat higher depending on the region due to labor costs. But it shouldn’t be much more than that.
Our foundation is somewhat special in parts (strip footing plus frost protection skirts on the exposed sides) and we have a ceiling drop — both of which are quite expensive. Therefore, a simple slab foundation with all wall surfaces insulated would probably end up costing roughly the same in the end.
This means, for the shell construction alone, excluding groundwork or interior finishing, you can expect around €750 (about $820) per sqm (approximately $76 per sq ft), though prices may be somewhat higher depending on the region due to labor costs. But it shouldn’t be much more than that.
Thank you for your input. In the meantime, I also spoke with a basement contractor. He said that for a standard watertight basement with about 90 square meters (about 970 square feet) of floor area (he had just calculated it), the rough construction costs (with an interior height of 2.5 meters (8 feet 2 inches)) with four light wells and 10cm (4 inches) of insulation (on the slab and exterior walls) are around €70,000 to €80,000, assuming no special foundation is required. Additional costs for earthworks and interior finishing will also apply. If I calculate 90 square meters at your rate of €750 per square meter, I arrive at €67,500, which is at the lower end of that estimate—but does not sound unrealistic… Thanks!
B
BBaumeister21 Sep 2021 15:05Overall, we spent around €70,000 for a 55 sqm (590 sq ft) basement. The ceiling height is 2.30 meters (7 ft 7 in), and otherwise everything is kept quite basic. Two rooms have tiles (installed by ourselves), one with a concrete finish and the other with vinyl flooring (also self-installed).
In der Ruine22 Sep 2021 11:27Wouldn't it be more practical to consider using the attic? With the right roof, a lot of storage space can be created there. Heating systems and other utilities can also be installed in that area.
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