Hello!
I want to build a pergola and need to have a 4.2m span. The largest beam that fits under the eaves is 45x145. Does anyone know how much weight it can support with such a large span without bending? They will be loaded with their own weight and overhead material of about 120-150kg. I could place two next to each other with a 45mm gap, how much would that affect the load-bearing capacity?
I want to build a pergola and need to have a 4.2m span. The largest beam that fits under the eaves is 45x145. Does anyone know how much weight it can support with such a large span without bending? They will be loaded with their own weight and overhead material of about 120-150kg. I could place two next to each other with a 45mm gap, how much would that affect the load-bearing capacity?
Dang. I was planning to lay slats on top, which would be about 150kg total distributed on each beam. I also wanted to attach a hanging chair or something similar to one of the beams.Lulaua said:
Yes, but then you don't have 150kg just bearing on one beam - as long as you skip the hanging chair (you can probably hang the chair on a beam near a pillar).
Make a simple sketch with measurements, and one can assess the feasibility a bit better!
Make a simple sketch with measurements, and one can assess the feasibility a bit better!
The red beams in the sketch are the 45x145 joists we are discussing. The idea was to place 45x145 joists on top as well all the way through.
The weight from the joists that lie on top is about 130kg per joist, and self-weight about 20kg. About 18 45x145 joists lie on top and there is 1.5m between the beams, they weigh 4.9kg per meter. But what I could do is attach more beams to the blue beam so that the weight per red beam is less. But the question then is how large the blue beam needs to be, is 45x145 enough?
The blue is not affected much by more red beams as it has a span of 1.4 m between the supports. It is the long span of the red beams, 4.05 m, that is difficult to manage. Is it not possible to use a larger dimension for the red beams?
The simplest way is probably to take 190 studs and notch out the top so they fit under the eaves. It is in the middle between the eaves and the support that the load on the stud is greatest, and the height of the stud is needed to handle the bending stress.
No, it's not possible, with 145mm I would have to cut a large hole in the roof eave, plus there's a gutter 1 cm above this. The ceiling is so low and most of the wall is covered with windows that the distance between the window sill at the top of the windows and the roof eave is the big problem, it's about 10cm...
The only option I seem to have is to break up the deck and place posts further in; I could set a row of posts with a 2.82m span. Then maybe I can even reduce the dimension to 45x120 and let the posts stand with 2.80x2.82 distance?
That might work. As it is now, I plan to cut about 5cm of the eave. But to fit 195mm, I would then need to cut 5cm off the beam as well, both for the eave and for the gutter. Will the beam still have better load-bearing ability even when it's cut out?GoC said: