I have an old barn that needs to be fixed up this summer. A new sheet metal roof instead of the partially collapsed tile roof. Unfortunately, a couple of the roof beams need to be replaced due to moisture damage. The beams are probably about 12-15x15cm thick. It will likely be necessary to replace them with some kind of joists. The question is, what dimensions do I need to replace these beams? How do you calculate, do 3 laminated 45x145 beams have the same load-bearing capacity as such a beam? Would it work to use, for example, one or two 195 or 220x45 instead?
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· stockholm
· 483 posts
it depends on how long the span you need, the truss construction, where in the country you live, and where in the construction the beams need to be replaced. Generally, one can say that roundwood is stronger than sawn timber, and glued laminated timber is stronger than both.
if you specify a little better, surely someone on the forum can calculate for you
if you specify a little better, surely someone on the forum can calculate for you
The beams are approximately 4.5-5m from wall to ridge. The barn is located outside of Hjo, so I guess it's in snow zone 2. The roof structure is old—I would guess the barn is from the late 1800s. There are beams up to a ridge supported by the gables and vertical beams at two places inside the barn. At these locations, there is also a horizontal beam for stabilization. It's a bit difficult to explain, but it's definitely not a modern truss construction. My idea was to try to replace the damaged beams with something equally strong, and that should work.
If you stand them on edge, they have the same strength even without glue-screwing. You just need to "nest" them together.grutt said:
If, however, you lay them flat, I don't think they'll be as strong, even if you glue-screw them!
In other words: Stand them on edge; nail or screw them together in a few places.
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