ᐅ Building a Concrete Garage! Three Walls or an Extension to the House? What Do You Think?

Hello everyone,

We are building a prefabricated house in NRW with the company Scanhaus Marlow Marlow. The building permit / planning permission process is currently underway. What was already clear to us beforehand is that Scanhaus Marlow Marlow is not involved in the garage construction. Therefore, we are currently focusing quite intensively on this topic.

After thorough research, we would like to have a concrete garage. For various reasons, we decided against steel. Unfortunately, it is very difficult for us to install a prefabricated concrete garage. The garage is planned to be placed on the left side of the house, under the roof overhang. The roof overhang has a height of 3m (10 feet) and is 1.20m (4 feet) wide. For this reason, hardly any prefabricated concrete garage manufacturers can install the garage at our location. Of course, there are also concrete garage manufacturers who produce "concrete individual parts" and assemble them on site.

We have now met with an architect who is going to design and estimate a masonry garage for us. He proposed building a garage with three walls plus a roof. The fourth wall would then be the house wall. From our house planning discussions, we know that no trades or fixtures may be attached to our house. The architect explained that the house does not have to bear any load or similar, as this is supported by the three garage walls. Of course, we understand that nothing can be attached to the fourth wall (house wall). This would be acceptable to us. An advantage of this idea is that we would save the cost of an additional wall and have roughly 20cm (8 inches) more space in the garage (due to the missing extra wall).

I have never heard of such a solution before. Does anyone have experience with this?
We have concerns regarding structural engineering, insulation, etc.

We would appreciate any feedback.

Best regards

Hello Kingstiefel

Regarding the structural engineering, I don’t see any issues there. The insulation is also straightforward. Overall, it’s actually a win/win proposal.
Most likely, a beam will be installed parallel to the house wall on the two walls. This beam will then carry the load.

Steven

Hello Klangstiefel,
I am familiar with both options.

My brother-in-law and I built two garages together (6.7m x 6m (22 ft x 20 ft) and 6m x 6m (20 ft x 20 ft)).
The structural engineer was the same for both projects.

My garage had four walls, the other one (6.7m x 6m (22 ft x 20 ft)) had only three walls. If it is properly designed from a structural perspective, there is no problem with that. It just requires more reinforcement steel in certain places.

Both garages have concrete flat roofs.

I hope this helps you.

Regards,
Sushi

Great, and thanks for the quick responses.

Two things just came to mind:
- Since we are building a prefab house... What could happen if, for example, a car crashes into the exterior wall?
- We plan to build the house with a timber frame construction and the garage out of concrete. That means different materials with, for example, different expansion properties. Do you see any issues with that?

I find this all quite complicated. Why not put the prefabricated garage in place first? That way, there is space for the truck. Then Scanhaus Marlow would build the walls and roof. This is exactly how it was done for us. Now the house and Rekers prefabricated garage stand side by side, and the joints between them are sealed with MS polymer, with an angle bracket added on top. Karsten

Hello kingstiefel

A prefabricated house is not a concrete bunker.
If you drive a car into it, you will probably end up in the living room. You can break through the walls with a decent hammer.

Steven