What dimensions for the ceiling?

[Da9911]

I am building a ceiling in an existing building, it will be insulated and have a gypsum ceiling, if you have, say, 4m between the walls, what dimensions do I need for the c24 wood?

Thank you in advance!

 

[Testarn]

If you don't plan on having any storage or living space in the attic, then a rather small dimension for the joists should suffice, such as 45x145, or even 45x120. We have about a 4m span on our upper floor from wall to load-bearing beam, and there we have 45x195, which is living space. Then you install counter battens 28x70 across the joists to screw the plasterboard into.

 

[Da9911]

If you don't need any storage or living space in the attic, a fairly small dimension for the joists should suffice, like 45x145, or even 45x120. We have about a 4m span on our upper floor from the wall to the load-bearing beam and we have 45x195 and it is living space.
Then you place a 28x70 batten across the joists to screw the plasterboard into.

Something like that I was thinking too, big thanks for the reply! 🥰👍