ᐅ Basement Insulation / Ceiling Height

Hello,

Unfortunately, we have discovered our first building mistake in our new house (which is still in the shell stage). The height of our basement is only 2.25 m (raw floor level) (7 ft 5 in). On top of this, screed + insulation + tiles will still be added (a total of 12 cm (5 inches)), which would reduce the room height to only 2.13 m (7 ft). Unfortunately, we were not aware of this low ceiling height during the planning phase. What alternative insulations or floor constructions would you recommend to correct this planning error as much as possible? I would be very grateful for any answers or further references.

Planned so far:
- Cement screed in the basement approx. 5 cm (2 inches)
- Standard insulation in the basement approx. 5 cm (2 inches) (no rigid polyurethane foam)
- 2 cm (0.8 inch) tiles (wood or laminate flooring would also be possible)

Facts about our house:
- Reinforced concrete basement
- Basement is used about twice a week for playing billiards
- Basement walls are exposed about one-third above ground level
- There is an option to connect a wood stove in the billiard room
- On the ground floor, underfloor heating + insulation + screed (a total of 15 cm (6 inches)) are planned
- The external walls (36 cm (14 inches)) and interior walls are made of aerated concrete

Could I, for example, cover the raw basement floor with wood fiber insulation boards including a substructure (thus avoiding screed)? Or would it make more sense to insulate the basement ceiling instead? Any changes in the basement should not cause us to have cold feet on the ground floor.

We would be very happy about any extra centimeters of room height ))

Have a nice day
mrwumm

Hello,

mrwumm schrieb:

The height of our basement is only 2.25 m (raw floor level). On top of that, there will be screed + insulation + tiles (a total of 12 cm), so the room height would only be 2.13 m (7 feet).

15 cm (6 inches) on the ground floor is already low; 12 cm (5 inches) in a basement used as living space is not acceptable either.

mrwumm schrieb:

What alternative insulation methods or floor constructions would you recommend to minimize this planning error as much as possible?

This is not a planning error; you simply bought very cheaply; now you have to live with the consequences.

Best regards

Bauexperte schrieb:
.... in a basement used as living space, are also not possible.

Using the basement as living space is likely not feasible. This is due to the insufficient clear ceiling height and the insulation. It is certainly located outside the thermal envelope (=> verification). Hopefully, the underfloor heating on the ground floor is designed to handle this additional load. About one-third of the basement wall height appears to be exposed directly to the outside air without protection! I consider a basement without living space functionality to be a poor investment.

@ mrwumm: Completely omit insulation under the basement floor or reduce it in thickness (=> PUR/PIR). According to the energy saving regulation, there are no requirements for floor construction in unheated ancillary rooms.

Best regards

Hello €uro,

€uro schrieb:

I consider a basement without residential use to be a poor investment.

Then it is a very expensive storage room.

Kind regards

Hello €uro,

I have also considered not insulating the basement. What I don’t fully understand is:
- Is the purpose of insulating the basement to prevent the surrounding air (inside the basement) from cooling down too quickly, or to keep the ground floor’s floor from becoming too cold, or both?
- What if I don’t heat the basement for, say, three weeks—does the type of insulation in the basement still make a difference then?

My parents (they have a round log timber house with a basement) have, for example, about 2.5cm (1 inch) of wood insulation laid on their raw ground floor in the ground floor, with a normal wooden floor installed on top. The basement in my parents’ house has a double garage, so it’s always mechanically ventilated and therefore always cold. However, the ground floor’s floor in their house always feels very comfortable temperature-wise (which would be perfectly sufficient for me and my family). Wood is known to insulate much better than masonry. Would it be possible to use something like this in the basement as well, and what should be considered?

Thank you very much for your answers
mrwumm

A small correction to the above post about insulation with wood:
At my parents' house, the structure consists of joists + insulation + covering and is therefore 8 cm (3 inches) thick. Does anyone here have experience with this type of construction?