Basement insulation / Room height

Hello,

Unfortunately, we have discovered our first construction mistake in our new building (still in shell construction). The height of our basement is only 2.25 m (raw floor). On top of this, screed + insulation + tiles (a total of 12 cm) would still be added, so the room height would only be 2.13 m. Unfortunately, we were not aware of this low room height during planning. What alternative insulations or floor structures could you recommend to me in order 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
- Standard insulation in the basement approx. 5 cm (no PUR)
- 2 cm tiles (wood or laminate would also be possible)

Facts about our house:
- Reinforced concrete basement
- Basement is used about twice a week for playing billiards
- Basement protrudes about 1/3 out of the ground
- It is also possible to connect a Swedish stove in the billiard room
- On the ground floor, underfloor heating + insulation + screed (total 15 cm) is planned
- The exterior wall (36 cm) as well as the interior walls are made of aerated concrete

Could I, for example, equip the raw basement floor with wood fiber insulation boards including substructure (thus no screed)? Or would it perhaps make more sense to insulate the basement ceiling instead? Possible changes in the basement should not result in us having cold feet on the ground floor.

We would be very happy about every extra cm of room height ))

Have a nice day
mrwumm

Hello,

The height of our basement is only 2.25 m (raw floor). In addition, screed + insulation + tiles would be added (a total of 12 cm), so the room height would then be only 2.13 m.

15 cm on the ground floor is already little; 12 cm in a basement used as living space is also not acceptable.

What alternative insulations or floor constructions could you recommend to me in order to eliminate this planning error as much as possible?

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

Kind regards

.... in a basement room used as living space, are also not possible.

Use of the basement as living space is probably excluded. Both because of the insufficient clear room height and the insulation. It is certainly located outside the thermal envelope (=> proof). Hopefully, the underfloor heating on the ground floor is designed accordingly to bear this additional load. One-third of the basement wall height is apparently exposed unprotected to the outside air! I consider a basement without living space characteristics a bad investment.

@ mrwumm: Completely omit insulation of the basement floor or reduce it in construction height (=> PUR/PIR). According to the Energy Saving Ordinance, there are no requirements for the floor structure of unheated ancillary rooms.

Best regards

Hello €uro,

I consider a cellar without residential use to be a bad investment.

Then it is a very expensive storage room

Kind regards

Hello €uro,

I have also already thought about not insulating the basement. What I don’t quite understand
- So do you insulate the basement to prevent the ambient air (i.e. in the basement) from cooling down too quickly, or so that the floor on the ground floor doesn’t get too cold, or both?
- What would happen if, for example, I don’t turn on the heating in the basement for over 3 weeks, would it still make a difference what kind of insulation I have in the basement?

My parents (round log cabin with basement), for example, have laid about 2.5 cm of wood as insulation on their raw floor on the ground floor and built a normal wooden floor on top of it. In my parents’ basement there is a double garage, which is always forcibly ventilated and therefore always cold. However, the floor on my parents’ ground floor always feels very pleasantly warm (so it would be completely sufficient for me and my family). Wood is known to insulate much better than a wall. Could something like that also be installed in the basement, or what would have to be considered there.

Thank you very much for your answers
mrwumm

small correction to the above post about insulation with wood: at my parents' place, the structure consists of storage wood + insulation + covering and is therefore 8 cm thick. Does anyone have experience with this structure?