Estimating shell construction costs for an extension - Who has experience with that?

Hello,

I am planning an extension to our house in about 3 - 5 years.

We have two children, but only one children's room. When the kids get older, each should have their own room. Therefore, it is planned that in about 3-5 years we will build an extension to our house. It should be two stories high. So two rooms stacked on top of each other. Each with approximately 4 x 4.5 m floor area.

The house is a brick house. I would like to build the extension at the back as a timber frame structure. Is that possible or could that cause problems?

Why am I already concerned about this? Because I am currently paying off my loan and I fear that interest rates will be significantly higher in 5 years, so I would like to set aside some money now for the extension instead of putting it into special repayments.

The question is, how much would such an extension approximately cost.
I am only interested in the following cost points:
- Foundation + floor slab
- Timber frame + insulation
- Roof

I will do the rest myself or can estimate it myself.

I really only want a rough cost estimate.
Should I expect around €20,000, or rather €30,000, or already towards €40,000?

Maybe someone here has some experience regarding this.

Thanks in advance!

Best regards
Specki

Just have it specifically offered to you. How is an unknown roof supposed to be estimated from a distance, for example?

You will also have to pay engineers one way or another, not just individual trades. Architect, structural engineer, surveyor.

I think you will have to invest a total of around 50k, even with [EL].

I think 50k will soon not be enough.

50k for everything or just for the shell construction including the roof?

I actually expected 40k for everything.
Windows + 1 door 4000,-
Two radiators + rerouting pipes 1000,- (own work)
Electrical: 1000,- (own work)
Floors: 1000,- (own work)
Whitewashing, possibly drywall inside etc.: 1000,- (own work)

Then basically only the "shell construction" (floor slab, walls, screed as well as roof) is missing.
I assume that should be doable for 30,000,- with two rooms of 18 sqm each, which are also stacked on top of each other.

Or am I so wrong there?

Regards
Specki

Oh yes, I meant everything. If you do the entire interior finishing and building services in EL, I think you can manage with 40k, maybe even less.

Groundwork? Intermediate ceiling? Exterior plaster + paint possibly insulation? What about the rainwater drainage and the window sills?

In addition, scaffolding work and site setup. What about the building permit + structural analysis?

I am usually optimistic about the costs here in the forum. But in Bavaria? Never ever...