Span length for ceiling joists?

[bopakoster]

Jag ska sätta upp innertaksreglar 45x145x4000 mellan takstolarna som sitter cc 1200mm. Mellan stolarna har jag satt mellanstycken 45mm tjocka på hammarbandet som är 70mm brett. Räcker 70-45=25mm som upplagslängd för innertaksreglarna?

 

[bopakoster]

[image] I will set up ceiling joists 45x145x4000 between the rafters that are spaced at 1200mm. Between the rafters, I have installed spacers 45mm thick on the wall plate, which is 70mm wide. Is 70-45=25mm enough as a support length for the ceiling joists?

The wall plate is two layers 45x70mm...
As mentioned, is it enough to place the attic joists on a surface of 45x25mm and attach them to the spacers, or do I need to cut a 45mm wide slot in them?

 

[KnockOnWood]

It might sound a bit insufficient.
but screw metal brackets to the standing träna, both in the floor joists and rafters,
so maybe that will be enough.

The braces in the picture, are they temporary just during the construction period?
How do you plan to support the building later, so it doesn't buckle?

 

[bopakoster]

It might sound a bit insufficient.
but screw metal angles to the standing wood, both in the floor joists and roof trusses,
so maybe it's enough.

The diagonal braces in the picture, are they temporary during construction only?
How do you plan to support the building afterwards, so it doesn’t buckle?

Thanks! I remembered now that I will put a layer of 45x95 studs across the roof (more insulation), which will also provide a better base for the internal ceiling studs then!

The diagonal braces are temporary, will be replaced with 2 perforated steel straps perpendicular to each other/wall. Two because the strap only takes up tensile stress.

 

[KnockOnWood]

I will place a layer of 45x95 beams across the roof trusses, I just remembered (more insulation) this will also provide a better support for the ceiling beams then!

Now I am really confused and do not understand at all how this roof structure should be constructed.
Does anyone else perhaps understand?

 

[bopakoster]

Thanks! I will remember to put a layer of 45x95 studs across the roof trusses now (more insulation) and that will also provide a better foundation for the ceiling joists!

The braces are temporary, will be replaced with 2 tension straps perpendicular to each other/wall. Two because the band only absorbs tensile stresses.

@KnockOnWood Since there are window and door openings in the walls, it's not possible to place diagonal tension straps between the wall corners. The wall in the picture above has two sections that are 1x2.4m. A tension strap cross there should work, right? It's the same situation on the gable wall, a tension strap cross over two sections that are 1.2x2.4m should be sufficient, right?

Or:
If the walls are clad with sheet material, they get a stabilizing function. I'm building with vertical siding on the outside and horizontal tongue and groove on the inside covered with 13mm gypsum. Could the gypsum be sufficient for lateral stabilization?

 

[bopakoster]

Now I'm really confused and don't understand at all how this ceiling structure should be built up.
Anyone else who might understand?

Sorry for my lack of clarity! I'll try to explain:
The ceiling structure consists of the trusses' bottom chord 45x145mm CC1200mm and in between, battens 45x145, so the structure consists of 45x145mm battens CC600mm.
Normally, furring strips for the ceiling are used, but I am instead adding two layers of battens to make room for more insulation and an electrical installation layer, first a layer of 45x95mm across the structure, then an additional electrical installation layer of 45x45mm across again.

PS: putting the insulation upwards instead (normal practice) is limited by the low roof pitch of 17°. DS
PPS: I did this in stage 1 of the house renovation last year, https://www.byggahus.se/forum/threads/renovering-av-gardshus-riva-helt-eller-delvis.337652/#post-3233757 one reason for two crossed layers was that I wanted the ceiling panels to run parallel with the long wall...and now I am continuing stage 2 with that construction. DS

Picture from stage one, shows the ceiling with the bottom installation layer's 45x45 battens under the 95mm insulation layer

 

[KnockOnWood]

OK, it sounds like you are handling it in a sensible way. Good luck with the construction!

 

[bopakoster]

OK, it sounds like you're solving it in a sensible way.
Good luck with the construction!

Thanks!