Collect floor plans of 150m2 for our house

A mansard roof is, I think, very expensive because it involves working with many dormers. I can hardly imagine that anyone can still afford that. Dormers are often limited in the development plan, sometimes even prohibited.

There are plenty of floor plans! Your Bien-Zenker house is a two-story building. For a living area under 150 sqm, preferably smaller, 4 bedrooms (one of them an office), and a generous utility room as well as storage space for 4 people, you should not plan a straight staircase, because it consumes unnecessary hallway space. It fits better on over 160 sqm.

I also find the desire to have a rectangular house somewhat naive. Although, in my opinion, you get a better room layout on a rectangular footprint, there are plenty of houses with an almost square footprint that don’t reveal their size because of a gable roof.

I think it’s great how committed you are to your niece, but researching knowledge, googling on the internet, and exploring costs should be left to the future homeowners. You are now presenting her with several houses, and she is supposed to "choose" something from the selection without knowing the background and considerations? She needs to know what else is out there besides your selection?!

And we all know: building a house often isn’t "I wish, I wish," but rather "what can I afford" and "what is even allowed."

Oh, of course. My niece collects a few things herself already. And yes, they are totally naive. There are three of them and together not even over 50 years old. So where should it come from? It’s even worse than described here. The floor plan isn’t that important to the two (+ the half). The most important thing to them is how the house looks from the outside. Totally funny. This will be fun! But don’t worry, they have 3 builder families as advisors. We will definitely still wash their heads. It’s a learning process. You can’t just cut too much from the start. Otherwise you take away the youth’s drive and joy in the building project. So we’ll keep the mansard roof option in for now. I agree about the stairs too. Takes up way too much space. But there are still 14m² left to 150m². Maybe you could still tweak the walls a bit. But half-turned would of course be better. So far I haven’t found anything perfect. It’s not that important anyway. I just thought I’d ask around. It’s called brainstorming here. In the end the architect will surely make something nice for the two. I could also sit down and try. Something simple and plain always works. Just for fun.

A mansard roof is, I think, very costly because it involves many dormers.

That depends on what type of mansard roof you build. A mansard roof is the two-slope variant depending on the preference for a gable roof, hip roof, or tent roof. In the first form, you have straight gable walls. Basically, dormers as well as roof windows are possible here – which predominate depends on the ratio of the two slopes.

Structurally, a mansard roof results in a purlin roof, which is more complex than a rafter roof.

Moreover, the desire to have a rectangular house seems somewhat naive to me. Although, in my opinion, you get a better room layout on a rectangular base area, there are plenty of houses with an almost square base area that you wouldn’t recognize as such due to a gable roof.

At least in the sense of my question whether it should be rectangular, I do not use the term rectangle only for the variant with unequal side lengths, but as a generic term including the square. In my opinion, square base areas have their advantages up to about 80* sqm, and from about 140* sqm, the rectangle with unequal side lengths is ahead again.

*) Referring to floor slab area, not total living area

And yes, they are totally naive. There are three of them and together not even over 50 years old. [...] The floor plan is not so important to the two (+ the half). The most important thing to them is how the house looks from the outside. [...] But don’t worry, they have 3 builder families as advisors. We will soon wash their heads.

Oh come on. So young, it doesn’t have to be their last house. Maybe they love having silly ideas in their heads and want to keep them even after the washing. Let them plan their colorful villa, including Mr. Nilsson. I had such a (very exciting) phase where I developed houses from the outside in. Where is it written that successful house planning absolutely has to start with laying out the floor plan?

... But don’t worry, they have 3 builder families as consultants. We will still wash their heads. It’s a learning process. You can’t just remove too much from the start. Otherwise, you take away the youth’s enthusiasm and joy for the building project. So, let’s keep the mansard roof option in for now. ....

And it’s the same everywhere: The others know exactly how the builders should build

I always have to amuse myself here when the young people know exactly what mom or dad need in the granny flat :P

Best regards in brief

Oh come on. So young, it doesn’t have to be the last house. ... Where is it written that a successful house planning necessarily has to start with the floor plan layout?

Well, it’s not quite that big that more houses would fit in. They have to make do with that one house for their whole life. And with such young families, it’s a bit tricky with the value retention. Villa Kunterbunt still costs 300 thousand euros but you won’t be able to sell it anymore. We all hope that the marriage lasts forever, but who really knows. So a little resale value wouldn’t be a bad thing.