ᐅ Costs With and Without a Basement

Hello,
I would like to try to get an overview of the costs involved with and without a basement for our planned semi-detached house.

• The plot (about 10.5m (35 feet) wide) is already about 1m (3 feet) below the street level.
• After about 14m (46 feet) on the left side, there is an adjacent barn built on the boundary (foundation about 80cm (31 inches) deep).
• The semi-detached house must be built on the left boundary. On the right side, there is already a retaining wall about 80cm (31 inches) high.
• The entire plot (368m² (3960 square feet)) therefore needs to be "filled" by about 1m (3 feet).
• About 50-80cm (20-31 inches) of topsoil must be removed, then load-bearing sand follows.
• According to the development plan, a 4m (13 feet) setback from the street must be maintained.
• With a basement, we would need about 7.5m (25 feet) by 10m (33 feet) for the semi-detached house.
• Without a basement, we need a utility room for the technical equipment (buffer tank for air heat pump, electrical connection box, washing machine, ventilation unit, etc.) and a garage to replace the basement. I would estimate about 7.5m (25 feet) by 11.5m (38 feet), i.e., 11.25m² (121 square feet) more area.
• The house will face the street with the gable side.
• Water supply for the basement is not an issue on this plot.

My current findings (+ = additional costs, – = cost savings):

Basement (concrete):
+ more excavation, area roughly the same as the slab foundation
– soil can be used to fill the garden
– slab foundation is cheaper
+ basement walls, basement ceiling, insulation, drainage(?) (approx. 30,000 EUR)
+ finishing: heating, screed, possibly windows, floor coverings, partition walls, painting, ventilation concept
+ possibly underpinning the barn (approx. 1,500 EUR)
– more living space in the basement (priceless)
+ less living space on the upper floors due to lower knee wall if basement windows are required
+ carport addition for tires, roof box, etc. (would otherwise go in the garage)
– fewer rooms on the ground floor
– resale value
+ interest on all additional costs

Slab foundation:
+ fill material for the embankment, compaction for slab foundation (7x11.5)
+ load-bearing slab foundation (approx. 15,000 EUR)
+ utility room on the ground floor = more enclosed space because house is 1.5m (5 feet) longer
+ finishing upper floors and attic
+ larger roof
+ more (inefficient) hallway space inside the house due to utility room
+ garage as basement substitute

Did I forget anything? Does anyone have experience with the cost estimates for the points mentioned?
Maybe this helps other home builders to weigh the costs a basement incurs.

To quote [USER=2942]@Bauexperte, "Nothing is as expensive as living space underground."

We would have paid about 40,000 to 50,000 more for a basement (finished living space in the basement), including excavation work. Our neighbors, who admittedly built VERY large, paid 18,000 just for the excavation.

Our home builder made a rough estimate that adding 60cm (2 feet) in width or length would have cost us around 16,000, so for 50,000 we could have had a house 1.80m (6 feet) larger.

Since we didn’t have the money, the question of whether to include a basement never really came up for us.

A basement is not the same as living space! It is utility space and only becomes living space with expensive finishing: the window sizes need to be adequate, insulation and heating must be installed... This costs money!
Many people eventually want to avoid using those unnecessary stairs. Basement space tends to be filled up, with only one or two rooms used for laundry and storage. This might not be an issue immediately after moving in, but when the children grow up, people long for fewer stairs inside the house. I am one of those people and that is why I built a new home.

Again. It’s always about the costs. Whether you prefer it personally or have to do it, for example, to keep the built-up area small, should be everyone's own decision. You can quickly find the other basement discussions using the search if you want to know more.

We paid about 55,000 for roughly 85 m² (915 sq ft), including earthworks, insulation, screed, plaster, stairs, etc., which I thought was reasonable.

ypg schrieb:
A basement is not the same as living space! It is utility space and only becomes living space with expensive finishing: window sizes must be appropriate, insulation, heating must be installed… that costs money!

In that respect, @ypg is not wrong.

We still decided to build with a basement because, on one hand, we have a gently sloping plot (see avatar) and on the other hand, we had a fixed plan to use the basement as a guest room & office as well as a hobby room (party basement).

Compared to our previous apartment on the third floor without an elevator, one extra staircase doesn’t really bother us—but that is our personal feeling.

We solved the lighting issue in the guest room/office with a light well, which at the same time also serves as a second emergency exit (required by the building authority).

Of course, a finished basement costs more than a slab-on-grade foundation, but with a (slight) slope and the common land prices here (450 EUR - 600 EUR per m² (450 EUR - 600 EUR per 10.76 sq ft)), it doesn’t differ that much.

Best regards,

Dirk

Tichu78 schrieb:
Well, you’ve paid for the plot anyway, whether you have a basement or not.

If you actually use the rooms regularly, that’s fine. Our basement is just full of junk. We only need about 10m² (108 sq ft) of storage space plus technical rooms.

Exactly, I just meant that sometimes the building plot (especially smaller, more expensive ones) leaves the builder no choice but to include a basement if a certain amount of living space is desired.

@DNL: Yes, that’s roughly how it is for us too...