Weight on roof

[PappasHammare]

What is usually the weight of an interior ceiling per sqm including joists and insulation?
Same question for a roof without insulation.

What does a wooden board actually weigh?

Found the below about roofs and they write 30-100kg/sqm. Sounds quite light.
https://www.traguiden.se/konstrukti...nsionerande-last-for-takbalkar-och-takstolar/

 

[larsbj]

What is the usual weight of a ceiling per square meter including joists and insulation? Same question for the roof without insulation. How much does a plank weigh? Found the following about roofs, and they say 30-100kg/sqm. Sounds quite light. [link]

To find out, you need to calculate each part separately. For example, an attic floor with a wood ceiling 20mm joists 45x195 and 300mm insulation. Spruce wood typically weighs 500kg/m3 Insulation 100 kg/m3

Wood panel 1mx1mx0.02mx500kg/m3= 10 kg/m2 Joists 1.7mx0.045mx0.195mx500kg/m3=7.5 kg/m2 Insulation 1mx1mx0.3mx50kg/m3= 15kg/m2

So a total of about 32.5 kg/m2, then you should add a safety margin for dimensioning.

 

[PappasHammare]

Thank you. Good information.
But where does 1.7 come from regarding the bjälklaget?

Then I have quite different 'bjälklag'/trusses.
I don't have any direct beams, instead everything is vertical 170x22 planks but 20cm CC.
But it's just a matter of summing up.

 

[larsbj]

Thank you. Good information.
But where does 1.7 come from regarding the floor structure?

Then I have quite different 'floor structures'/trusses.
I don't have any beams directly but everything is standing 170x22 planks but 20cm CC.
But it's just a matter of summing up

1.7 is the number of meter studs per m2.
1/0.6=1.6667~1.7