ᐅ Estimating Shell Construction Costs for an Extension – Who Has Experience?

Created on: 16 Oct 2018 09:10
S
Specki
Hello,

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

We have two children, but only one bedroom. When the kids get older, each should have their own room. So, the plan is to build a two-story extension in about 3 to 5 years. This would mean two rooms, one above the other, each with a floor area of approximately 4 x 4.5 meters (13 x 15 feet).

The house is made of brick. I would like to build the extension at the back as a timber frame structure. Is that possible, or could it cause any issues?

Why am I thinking about this so early? Because I am currently paying off my loan, and I’m worried that interest rates will be significantly higher in 5 years. Therefore, I would prefer to save some money now for the extension instead of putting extra payments toward my loan.

My question is: what would such an extension approximately cost?
I am only interested in the following cost items:
- Foundation + concrete slab
- Timber frame + insulation
- Roof

I will do the rest myself or can estimate it on my own.

I really just want a rough cost estimate.
Should I expect around 20,000, or more like 30,000, or rather closer to 40,000 euros?

Maybe someone here has experience with this.

Thanks in advance!

Best regards,
Specki
S
Specki
16 Oct 2018 13:35
Yes, I would have done all of that myself.
Since the question was about the roof shape, it’s a simple shed roof.

How does it look in terms of permits? Do I first need a complete drawing and then get it approved?
I basically have almost no documentation for the rest of the house, only a few very old documents, some of which are not entirely accurate.
Is that a problem?

My plan would be like this:
I go to a carpenter and explain what I intend to do and what he should build for me. He creates a drawing, which I take to the authorities for approval. Then the carpenter provides the structural calculations, and I have someone install the foundation slab first. Afterwards, the carpenter completes the shell structure with insulation and roof. The window installer fits the windows and door, and I will take care of the rest myself at a comfortable pace.
A
apokolok
17 Oct 2018 20:12
No, you’re still quite a bit away from reality.
With the mentioned self-performed work, I would estimate around 55,000-60,000 (currency not specified).
The plans must be submitted by an authorized professional, either an architect or a structural engineer.
Is the whole project even eligible for approval (building permit / planning permission)?
S
Specki
17 Oct 2018 20:18
I hope it is possible to get approval.
How can I find out? Should I approach the local authority with my plans?

Hmm, that’s definitely more than I expected. But well, I won’t know for sure until I get some quotes.
L
Lumpi_LE
17 Oct 2018 20:33
Go to an architect and have them tell you the cost. $50,000 and more for those few square meters with that much electrical work is very unlikely...
H
hanse987
17 Oct 2018 21:46
apokolok schrieb:

The plans must be submitted by an authorized building professional, such as an architect or civil engineer.

It does not have to be an architect or civil engineer. A master carpenter is also authorized to submit plans.
B
Bookstar
17 Oct 2018 21:58
The costs before finishing will be around 50,000 euros. You can manage the rest in electrical installations with about 10,000 euros. So in total, you are looking at at least 60,000 euros.