I am building the attached door canopy.
I need to sit atop it to finish top slates and ridge tiles. But I am concerned about it not being strong enough. I cant stop thinking about it. I am concerned the weight on top will push the rafters outward at the bottom.
I am not concerned about it pushing the rafter support beams out sideways, as I have notched a 2x6 over the beams to hold it in, so thats OK. I am more concerned about the rafters sliding out, but to do that the screws I put in need shear.
The images show red lines where I have put screws in.
The rafters birdmouths have 2 x 200mm x 8mm screws in through their top down into the main 6x6 beams on the sides. I did not toe nail them, but am thinking maybe I should have as nails would be better for the outward shear force on them than screws. I was trying to hide as many fastenings as possible.
The ridge board has 3 supporting screws in the front vertical post (probably 5mm stainless steel) and one screw diagonally down through the top into the house wall at the back, probably about 8mm stainless screw. These are more for support during construction rather than load, as the ridge board should self support if the birdsmouths hold up.
Additionally the back rafters have two screws each into the house wall to help them spreading also.
1) So I am mainly concerned about the screws in the birdsmouths shearing under weight. Its 10 either side (2 in each rafter). They probably wont, its probably OK, but I just want peace of mind it is.
2) I am then also concerned that the 12mm plywood I put on top was screwed in. There's probably 5 x 5mm stainless screws per rafter, so 25 screws in total per plywood board. Again, I think I should have had some nails.
I may actually nail the end of the rafters and a few through the membrane and plywood on top just to be safer, but I just wondered what the thoughts are on the current setup, if it sounds secure for my weight plus slate, then the plywood is OK long term with weight of slate.
The
I need to sit atop it to finish top slates and ridge tiles. But I am concerned about it not being strong enough. I cant stop thinking about it. I am concerned the weight on top will push the rafters outward at the bottom.
I am not concerned about it pushing the rafter support beams out sideways, as I have notched a 2x6 over the beams to hold it in, so thats OK. I am more concerned about the rafters sliding out, but to do that the screws I put in need shear.
The images show red lines where I have put screws in.
The rafters birdmouths have 2 x 200mm x 8mm screws in through their top down into the main 6x6 beams on the sides. I did not toe nail them, but am thinking maybe I should have as nails would be better for the outward shear force on them than screws. I was trying to hide as many fastenings as possible.
The ridge board has 3 supporting screws in the front vertical post (probably 5mm stainless steel) and one screw diagonally down through the top into the house wall at the back, probably about 8mm stainless screw. These are more for support during construction rather than load, as the ridge board should self support if the birdsmouths hold up.
Additionally the back rafters have two screws each into the house wall to help them spreading also.
1) So I am mainly concerned about the screws in the birdsmouths shearing under weight. Its 10 either side (2 in each rafter). They probably wont, its probably OK, but I just want peace of mind it is.
2) I am then also concerned that the 12mm plywood I put on top was screwed in. There's probably 5 x 5mm stainless screws per rafter, so 25 screws in total per plywood board. Again, I think I should have had some nails.
I may actually nail the end of the rafters and a few through the membrane and plywood on top just to be safer, but I just wondered what the thoughts are on the current setup, if it sounds secure for my weight plus slate, then the plywood is OK long term with weight of slate.
The
