Attic expansion, building law

Hello dear forum community,

Currently, we are trying to catch up on the backlog of renovations from recent years. The house has 3 floors, one of which is an attic apartment. Above that is the attic. The roof should be a gable roof; however, the technical terms are not familiar to me in this regard. The roof is now to be newly covered and insulated.

In this context, of course, we are thinking about an expansion but have no idea whether it is worth converting or rebuilding the very low attic space, as there is only space in width, not in height.

My question to you: Does it make sense to deal with this? How does the building law tend to look, and have similar conditions had chances in the past?

Attached is an approximate description of how this has been solved in the immediate neighborhood. Our current attic has no staircase access; this would have to be via the attic apartment.

Many thanks for your answers to a completely inexperienced homeowner.

Best regards

That absolutely depends.
What are the dimensions of the attic anyway?

Ultimately, a lot is solved with dormer windows to give the attic apartment more height and gain more space.
Of course, this somewhat reduces the attic, but most people gladly accept that.
An attic is usually just an empty space that is at most used for storage where things stand that you never move again :)

Do you want to convert the attic or the attic apartment?
The attic, with its presumably 1-1.5m height, is hardly usable without extra construction like in the drawing.

If you get the appropriate permits, no matter which direction you go, the question naturally arises whether it even makes sense.
You can assume that such a conversion as in the drawing will certainly not cost less than €50,000. Probably rather €70-90k.

If it has already been done in the neighborhood, you will probably also get the corresponding permit.

I don’t quite understand the drawing. Is that an additional structure on the attic apartment, meaning another floor on top, or is that the converted attic apartment?

I had my attic apartment extended with dormer windows. Two of them, each 7m long. The gain in space is really enormous, and there isn’t much left of my attic. I also wanted a roof terrace, but I didn’t get permission for that. Adding another floor wasn’t possible for me either.

I would only undertake a project that involves new insulation and a newly covered roof if there is really a need. For example, because of children, parents, family in general. Just because you can do it, in my opinion, it’s not worth it. You simply have to spend too much money, and if it just stands empty afterward...

Why do you want to convert the attic apartment?

Thanks first of all for the detailed answer.

So the attic apartment is autonomous.... The connection to the attic consists of a folding ladder. The size of the attic apartment is about 78sqm, the attic above is accordingly somewhat smaller.

The roof would need to be replaced in the next 10 years and then I also think insulated. The rest of the house is insulated. Basically, the focus is on the expansion, since we have one room too few in our attic apartment regarding family planning.

The potential of the attic apartment is basically exhausted, hence the idea to basically raise the roof. In principle, a new floor would then be created.

My penthouse apartment also had about 78m² and now, thanks to the dormers, just under 95m².
But of course, that doesn't help if the floor plan does not allow for another room.

If the roof needs to be redone in 10 years, then it absolutely makes sense to renew the insulation at the same time. Doing both separately is more or less nonsense. Although interior insulation should probably remain unaffected by the newly redone or to be redone roof.
However, I don't know how you could cover the total sum with a favorable KFW loan. You would have to look into that.

If you can add a storey and if this has already been done in the neighborhood anyway, then that obviously offers enormous potential for a nice penthouse apartment.
This way, you could make the bedrooms in the "lower floor" of the penthouse and have a spacious living and dining area with a nice roof terrace upstairs in the added storey (which I would, by the way, orient to the south/west).

And now to your questions:

In diesem Zuge denken wir natürlich über einen Ausbau nach, wissen allerdings überhaupt nicht, ob es sich lohnt, den sehr niedrigen Dachraum auf- / umzubauen, da nur Fläche in der Breite, nicht in der Höhe vorhanden ist.

You will hardly be able to make the attic space above the penthouse usable. An acquaintance of mine has converted the attic space in the two children's rooms so that the children have their sleeping area upstairs accessible via a staircase/ladder. They think it's great because it’s a kind of hideout and adventure.
But unfortunately, that doesn't help you with a missing room.

Das Dach müsste in den nächsten 10 Jahren gedeckt und dann denke ich auch gedämmt werden. Der Rest des Hauses ist gedämmt. Prinzipiell kommt der Ausbau in der Fokus, da wir in unserer DG Wohnung einen Raum zu wenig haben hinsichtlich Familienplanung.

Expanding space can also work without adding a storey. It entirely depends on the floor plan and how you have to adhere to the existing conditions.
A bathroom/WC and a kitchen will probably always have to stay where they are now. The reason is the drains/downpipes/water pipes.
Now you’d have to consider. Adding a storey will of course have the greatest and best space potential, no question. That would certainly solve all space problems. But probably also be the most expensive.
Another alternative is dormers. The gain in space here should not be underestimated. But you don’t necessarily gain another room through dormers. Here, the floor plan of the apartment would be interesting and, of course, the size dormers can be allowed to have in your case. If, for example, you can install a dormer along the entire length of the roof, then the new space in length could reduce the width of rooms and thus in the end even result in an additional room. At that point, the sleeping possibility directly under the roof, as my acquaintance has done, might also be interesting.
However, you have to like such a complex apartment and consider that children are not children forever and will eventually get older and, above all, bigger. Whether the space will still be enough then...
Cheaper than adding a storey but then possibly not worth it.

Meine Frage an euch: Macht es Sinn sich damit auseinanderzusetzen? Wie sieht das Baurecht tendenziell aus, hatten ähnliche Vorgaben Chancen in der Vergangenheit?

Of course it makes sense. Just go to the local construction companies/carpenters/architects and present your project. You can definitely look at various possibilities there.
Building regulations, you probably mean permits. Always depends on the municipality (as far as I know). If it has already been done in the neighborhood, it will surely be possible for you too.