I am sitting and planning to build a floor where our current attic is today. I have done a sizing of the joists for the second floor but now I am wondering about the current plank walls. Will they be able to handle an additional floor and above all, how can I obtain material data on a wall from '56?
If by plank walls you mean the type of wall that is solid planks, then there are probably no issues, compared to a load-bearing wall of studs that only has a stud every 600 mm, your plank walls are likely significantly stronger, how thick are the planks?
Check once more how the construction is. In our house, we had a double-plank wall that we thought was load-bearing; it was so thick! But it wasn't supported by anything and was only nailed to the floor (no floor under the wall). The load-bearing construction was a framework of round timber (presumably built in the '20s).
//Johan
//Johan