Choice of studs for exterior wall

[maah]

I am planning an expansion which can be read about here: https://www.byggahus.se/forum/threads/tillbyggnad-35m-hur-svart-kan-det-va.395747/

Now, as I sit and try to make a calculation and have come to the exterior walls, I am a little stuck on the choice of studs. The walls in the existing house are about 220mm thick and my idea was to have approximately the same thickness on the extension.

My idea was to build the walls 170+45, but when I look at studs on Beijer, it seems that 170mm studs are not available in short length (2500mm). Is it an unusual dimension to build with?

 

[ArneTW]

I am planning an extension that you can read about here:
[link]

Now that I'm trying to make a calculation and have come to the outer walls, I'm a bit stuck on the choice of studs.
The walls of the existing house are about 220mm thick, and my idea was to have roughly the same thickness on the extension.

My idea was to build the walls 170+45, but when I look at studs at Beijer, 170mm studs don't seem to be available in short length (2500mm). Is that an unusual dimension to build with?

Buy long ones and cut in the middle?

/ATW

 

[maah]

If I base it on what is available in stock at Beijer, it seems that 145mm is the most common for wall studs.

When I measure existing walls a bit more carefully, they measure 275mm from the outer panel to the drywall and I'm trying to figure out how they are constructed.
Drywall 13mm
OSB 13mm
Installation kit 45mm
Wall stud 145mm
Furring strip 25mm
Panel 20-30mm

That becomes about 260mm

Could it be accurate if you assume a 145mm wall stud?

 

[tergo]

you probably have a sheet of outer plasterboard or asphalt board externally as well, it could be those approximately 15 mm that are missing, or there is a membrane

 

[maah]

you probably have a sheet of outdoor plasterboard or asphalt board on the outside also, could be those about 15 mm that's missing, or there's a membrane there

I haven't checked what's there yet, but as you say, it's probably something like that.
The construction of the new walls doesn't need to be exactly like the existing ones, but it helps if you want the new facade to align with the old one.

 

[epw]

170 or 195 is commonly used Resvirke for extensions today. For new construction, you can step up to 220 if you have higher insulation requirements.

 

[Biffen87]

Recently did an extension of about 60 square meters in central Skåne, meeting energy requirements with 240mm mineral wool.
21 Panel-gles 28-exterior gypsum 10-195-plastic-45-OSB+gypsum 24, so about 320 mm thick walls.
So if a building permit is required, keep in mind that you need to meet the energy requirements.