Architect - Flat-rate offer instead of HOAI for single-family house

Dear community,

After much consideration, we have now decided on an architect with whom we have the best all-around feeling. The last meeting with him took place yesterday.
Regarding the status of our project: We are currently preparing the land purchase with the notary. After that, a single-family house with a granny flat will be built.

Now the architect has revealed the following to us:
1) His office focuses on planning services. Therefore, he would consider up to service phase 5. For the phases thereafter, he would suggest several site managers with whom he has had good experiences.

2) He does not bill according to HOAI. Instead, he offers a flat rate for the services from the beginning. He justified this by saying that he prefers planning certainty for both parties and does not approve of being motivated by a higher project volume.

Now I would like to make a calculation for the individual service phases, to determine the range in which an HOAI offer would be as a reference. Could you assist me with this calculation?
As an assumption, I would like to use €1.5 million as project costs with a normal single-family house difficulty level (III or IV?).

Would you initially commission service phases 1 & 2 and then continue commissioning afterwards? Is there anything else to consider?

Thank you very much!

A HOAI calculator should help you get a better overview.

Take a look at my thread exactly right below here, because I have the same question at the moment. has described it very well there and on his website. Our flat-rate offer (currently still for service phases 1-3) represents exactly the value that can be achieved through the chargeable costs for Zone III (which usually fits for a single-family house, as long as you’re not trying to build a Versailles copy) in the middle range. Accordingly, with service phases 1-2 and your chargeable (net) costs, you should end up somewhere around 15,000 euros. In which fee zone and especially in which range of fee rates your architect sees themselves can only be told by them.

Take a look in my thread just below here, because I have the exact same question right now. described it very well there and on his website. Our flat rate offer (currently still for service phases 1-3) exactly represents the value you would achieve via the chargeable costs for Zone III (which usually fits for a single-family house, as long as you don’t want to build a Versailles copy) in the middle rate. Accordingly, you should end up somewhere around 15,000 euros for service phases 1-2 and your chargeable (net) costs. Which fee zone and especially in which range of fee rates your architect sees himself can only be told by him.

Thanks! I have read through the entire thread, very interesting. I think I am really in an almost identical situation. The step-by-step approach with service phases 1+2 first also makes quite a lot of sense to me.

I also found your thoughts about construction costs fascinating. We are not under any time pressure and it is a good option for us to wait a bit to see if construction costs develop more favorably for builders again.

1) His office focuses on planning services. Therefore, he would be considered up to service phase 5. For the phases after that, he would propose several site managers with whom he has had good experiences.

On the one hand, saying up to service phase 5 indicates that he is at least serious enough not to offer only up to service phase 4. But putting on the architect protection glasses of , on the other hand, from "only up to service phase 5" one can also derive the reading that the planner might belong to those who do not make very precise cost estimates, which is somewhat corroborated by

2) He does not bill according to HOAI. Instead, he offers a flat rate for the services from the beginning. He justifies this by saying that he prefers planning security for both sides and does not approve of being motivated by a higher project volume.

because the hour of truth (or fiction) only strikes in service phases 6 and 7 when the bids "evaluate" the cost estimates. Aside from that, the attitude of not wanting to earn from cost escalation would be commendable in itself. A site manager (i.e. only for service phase 8)—whether an architect or an expert—would not help you much; I would leave no gap between service phases 5 and 8!!!

Take a look at my thread just right below here; I have exactly the same question. @11ant has described it very well there and on his website.

This probably means —but I have also written about this topic complex in your thread at as well as here: (and you have surely already come across enough hints leading to me as well as such to the house construction roadmap of the building pilot). Thus,

Would you initially commission service phases 1 & 2 and then continue to commission further phases? Is there anything else to consider?

should be questions long answered :-)

Up to service phase 5, on the one hand, indicates that he is probably at least serious enough to offer more than just up to service phase 4. But if we put on the architect protection glasses of , on the other hand, the interpretation can also be derived from "only up to service phase 5" that the planner might belong to the less precise cost estimators, which is

yes, somewhat corroborated, because only in service phases 6 and 7 does the moment of truth (or fiction) strike when the bids "evaluate" the cost estimates. Aside from that, the attitude of not wanting to earn from driving up costs would be commendable in itself. A construction manager (that is, only for service phase 8) - regardless whether architect or expert - would not help you much; I would not leave a gap between service phases 5 and 8!!!

Probably meant is - but also in your thread I wrote on this topic complex in , as well as here: (and you should certainly have already come across enough hints on the way to me, as well as such on the house-building schedule of the building pilot). Thus, these should

be questions long since answered for you :)

Were you referring to a time gap when mentioning the gap? Of course, I will then involve a construction manager at a certain time. The architect said he would suggest several site managers after his work, who have so far worked well with his clients.

He also informed me that he will continue to follow the project even after being commissioned. Probably rather passively...

11ant - I tried to read your HOAI guide. The link to episode 3 did not work.