Help with enlarging / framing existing stairwell opening

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New Member
Jul 22, 2023
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Hey all,

Location: Sweden

House: Log cabin / timber frame, approx 150 years old. 1.5 storey

Joist dimensions: 6" x 2"

Joist centres: 24"

Joist span: 16'

Renovating our log cabin here in sunny Sweden. 1st thing, I have tried to get a structural engineer to do calcs for a few things but no one seems interested here unless I employ an architect and the engineer works as part of the package, so unfortunately structural calcs are not possible.

I work in metric but I'm gonna write in imperial so please bear with me.

I want to enlarge the stairwell opening as part of a larger renovation project. I want to take it across into the next joist bay. This would make the overall opening approx 6' x 6' (across 3 joist bays). I understand I should sister the joists on both sides, and I should double the headers. There are no load bearing walls on the ground floor, its completely open plan below.

  1. Given I can't get calculations, would the image / plan below pass 'code'? or at least be safe? (to be honest half the house isn't up to regs but I just want to make this as structurally sound as possible)
  2. Do the sistered joists need to go in double hangers? Or can I just glue and screw the new joists onto the old?
  3. I'm not taking up the ceiling (v. old t&g boards), I want to join as many of the joists together as possible with hangers, but are there alternatives? E.G angle brackets?
  4. on the left hand side of the image below is the log gable wall. Rather than a 6 x 2 joists there are 2no 2 x 2s nailed into the logs. Can I sister a 6 x 2 onto this setup? Or should I just replace it entirely?
  5. Anything else I should be aware of?