I am going to build a roof over our patio and plan to do everything myself, but I am a bit unsure about which dimensions to choose for the beams. We will be using glulam and the roof will be 10 or 16mm twin-wall polycarbonate. Can anyone advise?
The roof will extend about 4.5m out from the house with a width of about 7m. On the outer edge, I have the option to use posts with about 6m center-to-center, and I plan to attach the outer support beam to these two posts. The posts are 95x95. For the outer support beam, is 56x225mm or 56x270mm sufficient, or do I need to move up to the next size, which I believe is 66x315mm?
What thickness of twin-wall polycarbonate roof is best to choose? We will not have any walls/glass.
The roof will extend about 4.5m out from the house with a width of about 7m. On the outer edge, I have the option to use posts with about 6m center-to-center, and I plan to attach the outer support beam to these two posts. The posts are 95x95. For the outer support beam, is 56x225mm or 56x270mm sufficient, or do I need to move up to the next size, which I believe is 66x315mm?
What thickness of twin-wall polycarbonate roof is best to choose? We will not have any walls/glass.
Västra Götaland can be anything from Tiveden to the Bohus coast, quite a big difference when it comes to snow load. Specify the location. The dimensions of the front beam you specified seem way too small. It's more likely about 90x405. Much depends on the snow zone and the house's roof, if there's a risk of snow pockets, for example. If you're not having any walls, there's no reason to choose 16 mm, is there?
Exactly, I forgot to mention that we live in Gothenburg. Thanks for the response! Ok, but if we add a third post roughly in the middle, how should we consider the dimension for the front beam then? Regarding the roof thickness; that's kind of what we're thinking too (that 10mm should be sufficient) but wondering if there's any reason we haven't thought of...?J justusandersson said:
Channel plastic roofs do not become more attractive as they get thicker. The only reason I can think of is better thermal insulation, and that is not relevant. If you place a post in the middle, 56x225 will work fine.
Ok thanks again for the response! And the cross beams from the house out to the carrying beam, what dimension do you think is appropriate there? Can you attach them to the carrying beam with a French screw or should you use a universal screw (like in the picture)? We'd prefer to avoid using a joist hanger there due to aesthetics.J justusandersson said:
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The span is too long for regular construction timber, even if the c/c distance is set to 600 mm. c/c 1200 mm 90x225, 600 mm 56x225. Universal screws will likely work fine, keep in mind that the load at the anchoring point can be several hundred kilos.