Hello,
we are planning to build a single-family house in Bavaria, and due to groundwater pressure in the soil, the fully waterproofed concrete basement will be quite expensive. The general contractor said, "the basement costs more than the above-ground living space." Is it really possible that increasing the size of the above-ground house by nearly the same usable area that is lost by omitting the basement results in cost savings? In other words, is a 150 m² (1,615 sq ft) house with an expensive waterproof concrete basement more costly than a house without a basement but with 150 m² (1,615 sq ft) of living space plus 50-70 m² (540-750 sq ft) of utility rooms (the latter with cheaper flooring, etc.)? The general contractor only had a few rough rules of thumb, which obviously didn’t apply well in this case, and did not provide any actual cost calculations. Strangely, he also refused to calculate both options side by side, saying it would be too time-consuming.
Does anyone here have real experience with this? It would be very helpful, thanks in advance!
Best regards
we are planning to build a single-family house in Bavaria, and due to groundwater pressure in the soil, the fully waterproofed concrete basement will be quite expensive. The general contractor said, "the basement costs more than the above-ground living space." Is it really possible that increasing the size of the above-ground house by nearly the same usable area that is lost by omitting the basement results in cost savings? In other words, is a 150 m² (1,615 sq ft) house with an expensive waterproof concrete basement more costly than a house without a basement but with 150 m² (1,615 sq ft) of living space plus 50-70 m² (540-750 sq ft) of utility rooms (the latter with cheaper flooring, etc.)? The general contractor only had a few rough rules of thumb, which obviously didn’t apply well in this case, and did not provide any actual cost calculations. Strangely, he also refused to calculate both options side by side, saying it would be too time-consuming.
Does anyone here have real experience with this? It would be very helpful, thanks in advance!
Best regards
Basically, the following applies to construction:
Civil engineering (substructure) is always more expensive than building up (superstructure)—assuming identical floor levels, so don’t compare a first basement level with the 21st floor. This makes sense because equipment like excavators, earth supports, higher requirements for waterproofing, distributing and possibly disposing of excavated material, and potentially groundwater pumps during construction add extra costs.
A basement is only cheaper than an identical above-ground floor if its finish differs from that of the ground floor or attic. For example, no plaster, small or no windows, lower clear height, no underfloor heating, and a comparatively basic electrical installation. And, of course, omitting the two most expensive rooms in a single-family home: the kitchen and bathroom. The relatively costly heating system is also typically calculated as part of the overall “house project,” so an additional basement usually only requires slightly larger dimensioning. This means almost no extra cost.
Therefore, the final cost per square meter for a basement can still be cheaper than the same area in the attic. But beware when talking about a real “living space basement,” such as a granny flat, with proper plaster, underfloor heating, electrical distribution board, kitchen and bathroom, “normal” ceiling height, lifting station, hardwood flooring, light wells, and a second emergency exit. This is more expensive than adding the same living space above ground! This only makes sense if you have enough room and land availability or can ignore the land price.
However, during the shell construction phase, a basement is always more expensive per square meter than the same area on the ground floor.
Whether you need one depends more on the plot. If it’s large and flat enough, choosing a basement can often be explained only by tradition (“Only a house with a basement is a real house”). Otherwise, you should start calculating and be aware of the disadvantages of underground spaces compared to above-ground ones.
PS: We have a basement. For a mid-terrace house, it’s incredibly practical.
Civil engineering (substructure) is always more expensive than building up (superstructure)—assuming identical floor levels, so don’t compare a first basement level with the 21st floor. This makes sense because equipment like excavators, earth supports, higher requirements for waterproofing, distributing and possibly disposing of excavated material, and potentially groundwater pumps during construction add extra costs.
A basement is only cheaper than an identical above-ground floor if its finish differs from that of the ground floor or attic. For example, no plaster, small or no windows, lower clear height, no underfloor heating, and a comparatively basic electrical installation. And, of course, omitting the two most expensive rooms in a single-family home: the kitchen and bathroom. The relatively costly heating system is also typically calculated as part of the overall “house project,” so an additional basement usually only requires slightly larger dimensioning. This means almost no extra cost.
Therefore, the final cost per square meter for a basement can still be cheaper than the same area in the attic. But beware when talking about a real “living space basement,” such as a granny flat, with proper plaster, underfloor heating, electrical distribution board, kitchen and bathroom, “normal” ceiling height, lifting station, hardwood flooring, light wells, and a second emergency exit. This is more expensive than adding the same living space above ground! This only makes sense if you have enough room and land availability or can ignore the land price.
However, during the shell construction phase, a basement is always more expensive per square meter than the same area on the ground floor.
Whether you need one depends more on the plot. If it’s large and flat enough, choosing a basement can often be explained only by tradition (“Only a house with a basement is a real house”). Otherwise, you should start calculating and be aware of the disadvantages of underground spaces compared to above-ground ones.
PS: We have a basement. For a mid-terrace house, it’s incredibly practical.
The basement isn’t very well finished, everything is minimal, and features like an expensive lift-and-slide door are missing.
My attic was really inexpensive.
So it will be a basement without natural light, truly just storage space and technical rooms.
Every cubic meter has to be excavated and disposed of.
What are the ceiling heights and roof pitch like in your case?
My attic was really inexpensive.
So it will be a basement without natural light, truly just storage space and technical rooms.
Every cubic meter has to be excavated and disposed of.
What are the ceiling heights and roof pitch like in your case?
We don’t know your plot.
How about increasing the footprint by 10 m² (108 sq ft) and giving the roof a steeper pitch?
Ground floor: HVAC, plaster materials, freezer, drinks, tools
First floor: Laundry, storage room
Attic: Hobby room, decorations, etc. (currently planned to be 45 m² (484 sq ft) with standing height)
Behind the garage: Grill, lawn mower, sunshade
How about increasing the footprint by 10 m² (108 sq ft) and giving the roof a steeper pitch?
Ground floor: HVAC, plaster materials, freezer, drinks, tools
First floor: Laundry, storage room
Attic: Hobby room, decorations, etc. (currently planned to be 45 m² (484 sq ft) with standing height)
Behind the garage: Grill, lawn mower, sunshade
We also built on a site with a high water table and therefore decided against having a basement. Even a waterproof concrete shell (also called a “white tank”) does not last forever, and eventually the basement will get damp. In our development area (which has existed for about 10 years), I have learned in the past 1.5 years of three houses where the ground around the house was excavated and a basement waterproofing company worked on them. That makes me glad we don’t have a basement. We use our attic (2.50 m (8 feet 2 inches) high in the center) for storage, and we also have an attached garage. That is more than enough space in addition to our utility room.
Best regards,
Sabine
Best regards,
Sabine
Hausbauer schrieb:
The plot is completely flat with mostly sandy soil, but offers very little space for outbuildings, so the extra-large garage with shed will not be possible. Well, some compromise will have to be made,We don’t know your plot, its size, or the zoning regulations (building permit / planning permission). Also, the definition of “extra-large” can vary widely.
So any advice can only be very general.
I would say: for example, with a 600 m² (6460 sq ft) plot and a floor area ratio of 0.3, 180 m² (1937 sq ft) can be built. Who really needs more space just for parking?
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