ᐅ Enlarging the Living Room / Extending the Concrete Ceiling?

Hello everyone,

I recently moved into a relatively new house, built in 2016. The house is built with solid construction. The wall blocks are Gisoton blocks, 42cm (16.5 inches) thick. The house also has a full basement.

As usual, you only notice some of the less optimal aspects once you’re living in it. In my case, the living room is too small, so I would like to enlarge it. To do this, the basement below would probably also need to be expanded (at least in one direction), otherwise I would have to block up the basement windows. I did a quick sketch to show what that might look like:

As you can see, part of the garage would have to go. For the roof, I was thinking of a simple pitched roof that would connect to the main wall of the upper floor.

The question is whether it is even possible structurally to extend a concrete ceiling like this, or if that is generally not feasible? Maybe in our case it would also be possible to support the ceiling from below with a steel beam?

It would probably also be easier to enlarge the living room only toward the garage side rather than in two directions?

Overall, is it a bad idea to take something like this on, or is it doable?

I haven’t gone very far with my considerations yet, but before I approach an architect or structural engineer, I wanted to ask here first. Maybe there are some good suggestions as well. Of course, aside from the structural aspects, many other questions would have to be clarified (building permits / planning permissions, utilities, etc.).

Thanks, spyfromtheeast

Would it possibly work in our case to support the ceiling from below with a steel beam?
Yes, you would need to replace the walls with steel beams; anything else would be far too complicated.

Would it probably be easier to enlarge the living room only towards the garage side instead of in two directions?
Yes, that would be much simpler.

Generally, is it a bad idea to take on something like this, or is it feasible?
If you have the budget... it will be a very expensive project. Maybe just add another room instead?

Regardless of the technical solution, I see several issues here. In your sketch, it appears that the property boundary is directly next to the garage on the left side (garage as a boundary wall). This means your house must comply with setback regulations there, and enlarging it is most likely not possible. Upstairs, the issue with the basement windows has already been identified – I also think expanding the basement is economically unfeasible.

As an alternative approach, how about considering the terrace area? Perhaps the current terrace could be converted into a (heated) conservatory or sunroom to serve as an additional living/dining area, and the terrace relocated?

Please upload pictures directly here in the forum. Not everyone wants to be redirected to other websites.

Is the garage built on the property line? And is it only 3 m (10 feet) wide? In that case, you likely will not be allowed to widen the living room towards the garage side at all.

@RomeoZwo *pat*

Lumpi_LE schrieb:

Generally, is it a bad idea to tackle something like this or even feasible?
If you have the budget... it will be quite an expensive undertaking. Maybe just add another room instead?

I don’t know your qualifications, but what’s your rough estimate for the cost? €10,000 (about $11,000)? €50,000 (about $55,000)? €100,000 (about $110,000)?
You know how it is, sometimes it just isn’t worth it that quickly ops:
Adding a room is unfortunately not possible due to lack of (building) space.

RomeoZwo schrieb:

From your sketch, it looks like the property line is right next to the garage on the left side (garage built on the boundary). That means your house must observe setback distances there, and expansion is probably not possible. You’ve already identified the problem with the basement windows above — I don’t think expanding the basement will be economically viable either.
As an alternative idea, how about the terrace area? Maybe you could convert the current terrace into a (heated) conservatory to use as an additional living/dining room and relocate the terrace?

There is also a basement window on the left side toward the garage; it’s just missing from the building plan (there’s nothing like a good architect ).
Yes, the garage stands right on the boundary. According to a brief inquiry at the local authority, a setback of 2.50m (8 feet) must be maintained. Since the garage is about 3.4m (11 feet) wide, I have less than one meter (about 3 feet) of space left in that direction. Although I wonder whether I might be allowed to reduce the setback with the neighbor’s permission. On the other side, the house stands directly on the boundary line next to the other neighbor and is practically attached to their garage.
A conservatory is not an option, but thanks for the suggestion.

Thanks for your responses.
Best regards, spyfromtheeast