Attic: Knee wall / roof pitch / air space economic planning

Hello everyone,

we are currently facing the decision on how we want to design our attic. Since we actually have all the "needed" rooms on the ground floor, only 3 rooms will be planned there as expansion reserves: storage, possible guest room/children's room/office & hobby room.

The floor plan (14.5 * 10.5) is so large that we basically don't care about hard-to-reach slanted roof square meters in the attic. The roof must have at least 30 degrees and be a gable roof.

My question is which option is the financially best solution in relation to well usable space:

[*]Roof pitch: 30 degrees + 0.5m knee wall + 0m air space (i.e., insulated setback from roof edge)
[*]Roof pitch: 30 degrees + 1m knee wall + 0m air space
[*]Roof pitch: 38 degrees + 0m knee wall + 0m air space
[*]Roof pitch: 30 degrees + 0m knee wall + 1m high recessed, insulated "air space" (Dr?)

Values I googled were approximately: 0.5m more knee wall about 10,000€, 1 degree more roof pitch about 800€. I cannot estimate the cost for an insulated air space – would the screed also have to be extended to the roof edge there?

I lean towards option 3 – since the roof is already very large. Thank you very much if anyone has some input here.

Why then become so steep and choose 38°?

We are currently having the floor plan discussion from Chrisi1906, who also wants to build a bungalow with a roof.

One of my designs has this roof as a result:


It is 28°, 0 cm knee wall, but 1150 cm wide.

Yours is 1050 cm wide, but you have to choose at least 30°, you should sketch that out to see what surfaces result. They should be in the area of the roof shown above.

Thank you. And from the financial side... what would probably be the cheapest of the above-mentioned options. 30 degrees is just the minimal roof pitch.

38° .. but then the roof pitch is such that the roof is higher than the masonry of the bungalow underneath. You should just draw everything and really make it dependent on the requirement.

The floor plan (14.5 * 10.5) is so large that the actually hard-to-reach sloping roof square meters in the attic "don’t matter" to us. A minimum of 30 degrees and a gable roof are specified from the roof.

Which planning status regarding are we currently talking about? Forced roof pitch, no real desire for these rooms, no separability of the room reserve: that sounds to me completely unlike the idea of investing more than what is unavoidable. Consequently, I would also not exceed the minimum roof pitch. A vacuum cleaner knee wall could, if necessary, be created entirely as a dwarf wall here (which you probably mean by "air space").

Thank you very much. And from a financial point of view... which of the above options would probably be the cheapest. 30 degrees is just a minimal roof pitch.

Not to build a bungalow! We have 28 degrees and that with air space. The roof slope is mega high... that has nothing to do with a pleasing 22 degree roof.