Renovate the old garage or build a new garage?

Hello everyone,

a friend and I are planning a new duplex instead of an old single-family house. We have already completed the planning and received the building permit.

I originally intended to demolish the old garage and build a new one. Then I realized that my new garage is almost in the same place as the old one, but it would be a bit smaller.

Would it make sense to keep the old garage and only adjust its size to the new plan? It would definitely need to be renovated, and I would need a new gate. But how can I know if it is structurally stable? Who should I hire for this task?

I am attaching the site plan here. The old house and garage are marked with yellow lines and the new ones in red.

Thank you very much
Best regards

My friend and I are planning a new duplex instead of an old single-family house. We have already completed the planning and obtained the building permit. [...] Then I noticed that my new garage is almost in the same place as the old one, but it would be somewhat smaller. Would it make sense to keep the old garage and just adjust its size to fit the new plan? It would definitely need renovation, and I would need a new door.

You are planning a duplex not partially, but entirely; and you recognize that an existing garage is suspiciously still useful. Those are two reasons to congratulate you: you seem, in the sense of Frau Birkenbihl, not only to possess a brain but also to use it. May this trait benefit you for a long time and greatly! I therefore only disagree slightly at one point, namely that I also consider the door to be good. My recommendation is therefore: have the second single garage as well as a joint extension filling the corner built by the company Bimsfertigbauten Hoffmann. Although they are in northern Rhineland-Palatinate, to my knowledge they operate nationwide and are, from my deepest conviction, the first choice for garages. I know plenty of theirs that are still in top condition even after about fifty years. They are built on-site, from the foundation slab to the (flat) roof, from pumice slabs. With this system, garages can be built to centimeter accuracy following even slanted boundaries. It is best to discuss the timing with them immediately (i.e., whether they share my assumption that it is best if they come after the shell of the new house is already standing).

Thank you very much for your feedback

I therefore only have a slight difference of opinion at one point, namely that I also consider the gate to be fine.

I assumed that after adjusting the old garage size, it would no longer fit. I can check that.

Do you think it would be possible to demolish the old house and part of the old garage (to adapt them to the size of the new plan) without compromising the stability of the garage?
I think I need to have this concept (and the garage itself) checked by an expert, but I don't know which expert should do this.

My recommendation is therefore: have the company Bimsfertigbauten Hoffmann build the second single garage as well as a shared extension filling the corner. They are located in northern Rhineland-Palatinate, but as far as I know operate nationwide and are, in my deepest conviction, the first choice for garages. I know plenty of theirs that are still in top condition after around fifty years. They build on site, from the foundation slab to the (flat) roof, from pumice panels. With this system, garages can be built with centimeter precision, following even slanted boundaries. It’s best to arrange the timing with them right away (i.e. whether they share my assumption that they should come best when the shell of the new house is already standing).

Thank you for the recommendation. I will pass this on to my friend, who owns the other single garage.

I assumed that after adjusting the old garage size, it would no longer fit. I can check that. Do you think it would be possible to demolish the old house and part of the old garage (to adapt them to the size of the new plan) without compromising the stability of the garage? I think I need to have this concept (and the garage itself) checked by an expert, but I don't know which expert should do this.

Did I praise you too early? - The expert is called "common sense" (Härddie is the name of the judge), that reusing only two walls of the existing garage with two new walls and a new ceiling would be a hoax or a ten days late April Fool’s joke. Of course, you leave the garage standing as is and only make a passage in its back wall into the shared annex for tools, tire hotel, and so on. You build this annex together (you don’t want to be that crazy as to open a case from several separate ownership areas just for the little three-part garage stuff) with the second single garage. Using the existing garage only halfway as "building material" for a newly permitted garage would be the most disproportionate nonsense of "really Schilda quality." Either do a revision of the plans or forego realizing the building permit regarding the garage part; garages, which to my knowledge are procedure-free, will simply be built later separately if you don’t want to include them now in the permit of the overall project. But adapting a garage to a permit would be absolutely like a tail wagging the dog. That would top every "only" backward harnessed horse.

P.S.: I just noticed, the existing garage already seems to have an extension, and extends all the way to the border corner? Then I don’t understand your talk about its expansion for five cents. Show me details of the existing plans and the new building plans. You are also welcome to talk to me personally about it; the way should be known by now. We are talking about around 20,000 EUR, which can easily be saved solely through consistent reason.

that a reuse of only two walls of the existing garage with two new walls and a new ceiling would be a prank or an April Fool's joke ten days late.

No, not like that. I was wondering if it is possible to partially demolish the additional 3 meters of the existing garage. Then I would have the old garage with its ceiling as usual.
The old garage is about 9 m long, while the new garage would be only 6 m long.

just make a passage in its back wall into the shared annex for tools, tire hotel, tralala. You leave this annex together

P.S.: I just noticed the existing garage already seems to have an annex, going all the way to the corner of the property?
Then I don’t understand your talk about enlarging it for a penny.
Show some details of the existing plans and the new construction plans.
You can also contact me personally about this, the way should be known by now.
We are talking about around 20,000 EUR, which can be saved mercilessly just by consistent common sense.

I do not intend to have such an annex, and I wanted to remove that partition wall anyway.

I wanted to reduce the existing garage by partially demolishing the additional part, not enlarge it.

Did I praise you too soon? – The expert is called "common sense" (Härddie is his name), that a reuse of only two walls of the existing garage with two new walls and a new ceiling would be a prank or an April Fool's joke ten days late. Of course, you leave the garage as original and just make a passage in its back wall into the shared annex for tools, tire hotel, tralala. You leave this annex together (you surely do not want to be crazy enough to open a barrel from several separate ownership areas for that little three-part garage stuff) with the second single garage.

Using the existing garage only half as "building material" for one of the approved new garages would be most unreasonable nonsense of "truly Schilda quality". Either make a retouch to the plans or refrain from implementing the building permit regarding the garage part; the garages which are, to my knowledge, exempt from procedures by themselves are simply "later" built separately if you do not want to include them now in the overall project permit. But adapting a garage to a permit would absolutely be the tail wagging the dog. That topped every "just" harnessed horse from behind.

I would either do this partial demolition if it makes sense (and if the old garage is structurally stable) or simply do a complete demolition and build a new garage.