Duplex construction: Joint or separate developer?

We would like to have a duplex built with 2 families. The plots have been purchased, how should we proceed? It would probably be easiest with the same developer who builds everything simultaneously. Do developers agree to 2 contracting parties? How are the costs divided? Or should each family find and commission a developer for one half of the duplex and build independently? Perhaps there are experiences or recommendations. Thank you

You can, for example, "choose" a general contractor. He would then make proposals according to your wishes and submit separate offers for you and the other family. Of course, he can (and will) issue separate invoices. Overall, simultaneous execution of the work is obviously a great advantage for him, which you should notice in the price.

Of course, this also works with an architect who can take over planning and execution.

I would not choose different methods/contractors for the semi-detached houses. Some efforts would then be duplicated, and the aforementioned price advantages would probably no longer be present.

Good evening,

a well-meant piece of advice beforehand: before you sign anything at all, you should first familiarize yourself with the processes involved in house construction. Either through lectures, consultations, or here in the forum; that is better

Simply put, it would probably be the same developer who builds everything simultaneously.

Less prone to errors in any case.

Do developers agree to 2 contracting parties?

Sure, there are 2 contracts for work with 2 contracting parties each.

How are the costs divided?

Not at all; it results from the respective contracts.

Or should each family find and hire a developer for one half of a semi-detached house and build independently of each other?

I would not recommend that, and if so, bring both builders to the table before construction begins

Rhenish greetings

Overall, the simultaneous execution of the work is of course a big advantage for him,

Mutual

which you should notice in the price.

Nope. The savings are limited to the site setup and the omission of the exterior plaster on the party wall. The houses still have to be built solidly; noticeable savings can only be made on the small "nice to have" items even with a semi-detached house.

Rhenish greetings

Reduced setup times; advantages in the delivery of materials because (quite simply) only one trip is required each time (if everything fits on one truck). Basically, two construction sites (due to two contractors) are more expensive. Additionally, there are likely to be advantages in the margin. Possibly there is a kind of "small quantity discount".

There may be a kind of "small quantity discount".

You can call it that

Rhenish greetings