Visible wooden rafters in the living room on understructure and drywall?

Hello,

we are planning to realize an exposed wooden rafter ceiling in the living room. The living room has the dimensions 7x5m and is 5m high.
The ridge board is 16cm wide and 30cm high. On the wooden structure, drywall will be installed, on which the wooden rafters will finally be screwed.

The wood for the rafters should match the ridge board (spruce - construction timber) and be 10x10 or 12x12 or 12x10 (we haven't decided yet).



Is there any reason against screwing the wood onto the drywall and the substructure (25mm)? Or should we rather attach it to the purlins?

Does anyone have experience with this topic?

It should look something like this:

We built similarly. We had the wall above the kitchen set back 2m to create a gallery as a children's play/retreat area with many books and games. We didn't like this wall to the open space, to stick your head through, in a show home, and the visible beams were too much for us. I would never screw the beams to drywall because of the weight.

The drywall ceiling is already hanging on the slats, I wouldn't also tack a 12×12 solid wood beam to it. That already has a considerable weight, such a 12x12x6000 solid wood beam.

The decision is quite late. It should have been executed as a skylight right from the start.

How does the carpenter intend to execute it?

Show the lower support from both sides. One side has the ring beam to which it can be attached. Unfortunately, the other side is not visible. Somehow there is also a skewed angle there??

Is there a section or a plan of the roof construction?

The easiest way is to screw above the rafters. The screws are recessed by a few centimeters and then wood caps put on. If done well, it won’t be visible.

Is the purlin BSH?

I would either make the fake rafters fake as well (hollow inside) or 10*16 BSH; otherwise, the rafters might twist if you’re unlucky.