Fee for an extension/addition

Good day,

we are planning an extension to an existing building. A roof addition is to be made, as well as a garage to be built, which should also serve as a terrace. A wall on the existing structure also needs to be broken open. We have now received an offer from an architect, which is based on 332 cbm of built space and total gross costs amounting to 103,000 €. This includes the architect's fees of approximately 5,000 € (including planning, structural analysis, and applications, etc.) and about 7,000 € (construction supervision and awarding, etc.). The entire project is to be handled with the architect. Are these values realistic or how can I estimate the costs for this?

Thank you very much Max

These construction costs correspond approximately to the level of a non-basement new building on a greenfield site with a medium standard; for such a conversion or extension, they are rather conservatively estimated. In my opinion, this is only a rough estimate based on m3 prices, but I do not want to question the colleague's detailed estimate with this. The 12,000 fee corresponds to the HOAI minimum rate for residential buildings plus the lowest conversion surcharge. If services of a structural engineer are also included, then you are essentially getting those for free.

Hope I could help you.

The fee is already reasonable. Nevertheless, the local site visits for construction supervision must definitely be specified in quantity.

These construction costs correspond approximately to the level of a newly built house on a greenfield site without a basement with an average standard, which is rather on the low side for such a conversion or extension. In my opinion, this is just a quick estimate based on m3 prices, but I do not want to question the colleague's detailed estimate. The 12,000 fee corresponds to the HOAI minimum rate for residential buildings plus the lowest conversion surcharge. If services of a structural engineer are also included, then you are already getting these for free.

Hope I could help you.

...ehm

What exactly does it mean that construction costs are higher by a factor of 10?

The price of 103,000.-- EUR is gross, as is the fee of 12,000.-- Euro. The pure construction costs therefore amount to about 91,000.-- Euro gross – or did your remark about net construction costs only refer to this fee calculator?

But you are right, he calculated these costs based on m3 and m2 prices and then made an average value from that. I was assured that these costs for this project are realistic after all. Furthermore, the fee is a fixed price including structural analysis.

The building application is now finished and we simultaneously received the invoice for 5,000.-- Euro, which should be paid immediately. In retrospect, this seemed like a high amount to me. I am unsure whether this is correct in this amount, even though structural analysis is included.

I would be very grateful for an answer

Max

My reference to net only applied to this fee calculator. By "factor-10" I meant that the construction costs will be about an order of magnitude higher than the fee. Deviations in construction costs therefore have a far greater impact than small differences in a fee.

Regarding the m³ prices:

According to the work on normal construction costs NHK95 and NHK2000, a statistical work on new construction costs, the m³ price for non-basement single-family houses E + roof, medium standard, is around €276. This also corresponds with the estimate of your planner.

Regarding the €5,000 fee:

Up to the approval planning stage, the architect's fee – minimum rate + 20% renovation surcharge – amounts to approximately €2,900 net; for the structural planning (minimum rate) approximately €2,400 net. The advance payment claim roughly matches this. However, the fee for the approval planning is strictly due only when the building permit is granted – i.e., success-dependent! Usually, however, a payment schedule is agreed upon, as in your case.

That is then also acceptable.

Thank you very much for your information – you have really helped me a lot!