Move out support legs

[rostra]

How do you calculate how far you can move out support beams? In our 1.5-story house (built in 1966) with a framework roof, the support beams are placed at different distances into the room. Now, we would like to move some of them further out towards the outer roof to gain a bit more floor space. Can they be moved 40 cm without problems? Some of them are already positioned closer to the outer wall, i.e., at the "correct measurement". Does it help to oversize the new support beams?

 

[imported_Byggaren]

If it's a framework truss, improving the dimension of the support legs doesn't help. The issue isn't there, but in the rafters and the floor joists.

If you move the supports out (so they are closer to the outer wall), the free length from the middle wall to the support becomes longer, which positively affects the moment in the subframe/beams. But for the rafters, it's the opposite since the length between support and collar tie increases. It also affects the static stability of the frame.

Without knowing the span, timber dimensions and quality, as well as the roof pitch and snow zone, it is therefore impossible to answer your question.
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Byggaren