Loft, framework, dimensioning

[jaxp]

Hi
I'm planning to build a loft, approximately 3.2*4 m. Since I don't want "posts" on the floor, the joist will span the width of the room: 3.2 m.  
Can anyone suggest sizing/tell me where I can find sizing rules?
To make the floor as thin as possible, how closely should the joists be placed and what material should I use for the floor?
Surely it's good to soundproof in some way...
And there are surely more good questions that I haven't thought of yet.

/Jonas

 

[Mats]

Generally speaking, the closer the spacing between the studs, the smaller the studs, but I don't have the right knowledge to calculate it straightforwardly.

 

[jon_h]

With a span of 3.20, I wouldn't build with anything thinner than 45x170 at 300 c/c or maybe 45x195 at 60 c/c. You can choose the flooring material based on your preference, but either floor planks or chipboard+surface flooring. Between the beams, you should place some form of insulation for soundproofing purposes, like mineral wool.

 

[swecul]

with a span of 4.20 then, with a ½ floor, what should one have there?
the wall height will be 70cm... if that makes a difference...

 

[jon_h]

with a span of 4.20 then, with a ½ floor, what should one have there? the wall surface will be 70cm... if that matters...

45x220 is what you need in that case if you want 60 c/c. You can also go with 45x195 at 30 c/c.

These dimensions are for you to get a stiff and comfortable floor. You could use significantly thinner materials without them breaking, but then it would be bouncy.

 

[swecul]

do the wall studs also need to be extra strong to support everything?

 

[jon_h]

do the wall studs also have to be extra strong to be able to support everything?

Now I don't quite follow, which wall studs do you mean? Do you mean in the exterior walls on the ground floor?

 

[swecul]

yes, the exterior walls, they will presumably be the same on the ground floor as on the upper floor?

 

[jon_h]

I don't understand at all anymore. Are you going to build an entire house? Not just hang out in a loft in an existing building? And you say the wall studs should go up to the upper floor, are you going to have two complete floors? And then you're asking if the wall studs should be "extra" strong to support what exactly? The floor joists for the loft? No, not extra, but they should be dimensioned to meet all the requirements the construction demands of them. What is it that you're planning to do..?

 

[swecul]

I don't follow at all anymore. Are you going to build a whole house? Not just hang out in a loft in an existing building? And you're saying the wall studs should go up to the second floor, are you going to have two full floors? And then you're wondering if the wall studs should be "extra" strong to support what exactly? The floor joists for the loft? No, not extra, but they should be sized to meet all the demands that the construction imposes on them. What exactly are you planning to do..?

Ha ha ha ha! ;D

you answered my question anyway!
yes I'm going to extend my house and on the extension I want 1½ floors...
but raised wall life of 70 cm, that´s it.

 

[jon_h]

Okay.. In that case. Good luck

 

[Lilljonte]

For wall studs, I would use 45x195 and for floor joists 45x220. If you don't want "regular" trusses, to create a good space in the loft, I would place a laminated beam as a ridge and use 45x195 as rafters. If you go to http://www.svensktlimtra.se/, you can see which dimension to choose for the laminated beam. The floor should be soundproofed with some form of insulation as previously mentioned in this thread. To prevent cold drafts, you should insulate the roof on both sides if you understand what I mean. 195 mm of insulation between the rafters and then you add a cross beam and insulate with the thickness you desire (depending on where you live). Good luck!