The corners will have 140x140 glulam as it fits well with the sliding sections. Then have horizontal 140x225 as a load-bearing beam where the sliding sections are attached at the top. The roof beams will be 45x225 with cc about 1000mm and the span is 4m. The idea is to have 32-50mm polycarbonate roofing. Is glulam a better choice for tensile strength and to prevent warping? Let's say 42x180 glulam as a roof beam.
Ideally, I don't want a cross beam like this for aesthetic reasons. Do you see any problems with this? Is there a risk that the 45x225 roof beams will warp and I’ll need something crosswise for that reason?
Sure, with a white-painted cross beam it doesn't look too bad, but is it necessary if I want to avoid the risk of them moving too much?
Ideally, I don't want a cross beam like this for aesthetic reasons. Do you see any problems with this? Is there a risk that the 45x225 roof beams will warp and I’ll need something crosswise for that reason?
Sure, with a white-painted cross beam it doesn't look too bad, but is it necessary if I want to avoid the risk of them moving too much?
Last edited:
Glulam is more stable and does not warp to the same extent as regular studs, but the cost is much higher.
220*45 with quality C24 holds provided the studs are braced against buckling.
A tip is to paint the topside of the roof studs white for a nicer appearance; otherwise, they will cast shadows on the plastic roof.
220*45 with quality C24 holds provided the studs are braced against buckling.
A tip is to paint the topside of the roof studs white for a nicer appearance; otherwise, they will cast shadows on the plastic roof.
As I understand it, it's important that they are white on the top so you get the same temperature too. If the roof studs were black on top, there's a risk that the channel plastic will crack because it gets warm on just a certain part of the sheet.huggan said:
Thanks. I will do as in the picture above. Brace 2 places on these 4m and use 45x225 glulam.
I do not recommend channel plastic and regular battens for roof trusses. This is because the supporting surface of the channel plastic on the roof profile is no more than 10-12 mm. Regular wood twists and bends too much, and the channel plastic can slide out. Crossbars are used on roofs with channel plastic when the length of the roof exceeds 2.5m.
Use 56x225 roof rafters, you should be able to handle snow load without too much deflection. The transverse one (which should NOT be recessed as it weakens the rafter) should not be needed if the center-to-center distance is okay considering the length.
The same with the glass section, what is the span?
I made a glass roof, with 56x225 (but only 3m), and one of the supporting beams at the end became a 66x315 to handle deflection...
The same with the glass section, what is the span?
I made a glass roof, with 56x225 (but only 3m), and one of the supporting beams at the end became a 66x315 to handle deflection...
Old post from you, but I am currently looking for information on cross beams for channel plastic roofs.V verktygsgurun said:
I reacted to your response about using regular wood with channel plastic. It seems unlikely since the aluminum profile (60mm wide) along the truss is screwed with c/c 300mm. So you mean the wood can manage to twist this profile?