ᐅ Attach the purlin of the patio roof to the rafters of the main roof

Hello everyone,

We want to build a patio roof, but the “wall” beam should not be attached directly to the house wall. Instead, it will be placed below the gutter of the house roof drainage system. I have already seen several ways to fix the beam there.

One option is special connectors that are screwed onto the rafters, and the beam can then be screwed onto the flange plate (see photo). In my case, this would mostly be hidden by the soffit (no visible rafters).

Another common method I have often seen is screwing the beam from underneath into the rafters (also see photo). Here, I wonder which bolts are used, since the rafter is only 6 cm (2.4 inches) thick.

How have you solved this if you have used this mounting method? The beam itself will also be supported on the left and right by posts so that not all the load is transferred to the house roof structure, although that should not be a problem.

Best regards

Search for flange head screws; they are also available in the length you need.

Why make it so complicated? Because of external thermal insulation composite systems (ETICS)?
In that case, I would also install uprights on the house wall. To me, it seems too risky to attach it directly to the roof structure. There are already significant additional wind and snow loads on such a canopy. I wouldn't be confident that the roof has enough tolerance for that.

Hello, well, first of all, I have an 80cm (31.5 inches) roof overhang on my single-family house, and for both aesthetic and practical reasons, I don’t want to enclose it with a patio roof (I also wouldn’t know how to mount or attach it in the limited space between the patio roof and the soffit). Visually, I always find it looks very unprofessional, and there are spotlights installed there that I would be obstructing. Additionally, if something ever needed maintenance, you wouldn’t be able to access it because of the patio roof.

Therefore, I plan to install a purlin at the end of the rafters and start the patio roof from there, just beneath the gutter. This way, less roofing material is needed, etc. 😉

Apart from that, mounting it directly on the wall is also problematic because it’s a timber frame construction with cladding. I wouldn’t know where the wooden studs are behind the cladding to screw into properly, since it shouldn’t be attached only to the cladding. Behind the ventilation gap, there is a wood fiberboard panel that wouldn’t support the load either.

Understood. But as I mentioned, I would (additionally) work with vertical supports on the house side (and a concrete foundation). These can also be positioned slightly further away from the house, depending on the roof overhang.

Sure, it might not look perfect, but relying solely on the rafters seems too risky to me. Besides, such a post can also be useful for attaching plant pots, decorations, and so on.

I would not worry about the static snow load, but dynamic wind load can damage your house. For me, the solution would be a load support system with two posts in the garden or a cable tension system rated to withstand wind force up to level 8.