I'm coming to the end of fitting the first floor joists in a new extension, they are 250x47 spanning 4.15M. I had only intended to put in a single line of struts (full depth timber) down the center but have ended up putting in 2 extra lines of noggins along the ends of the joists in order to pull out all the bends and twists that have formed. This has worked well but I can't do anything about the bends in the vertical plane (about 20mm in the worst case) but I will be able to pack above/below for floor/ceiling so it'll be OK in the end.
The SE's spec asked for C16 stress graded, dry, preservative treated SW timber - which is what I used. I inspected in on the wagon when it arrived, it was nice and straight and dry. I stored it correctly supported and under cover and it's all been installed in the dry ---- so why is it all b****y bent and twisted?
I'm concerned because the next job is the roof which will be constructed from similar C16 timber but 175x47 with a rafter length of 7.2M.
My questions are:----
1).Is there any better grade of timber out there I could use that is guarenteed to be straight?
2).I've had a quick look at engineered timber 'I Beams' but they seem a bit of a faff for the roof which has a few complicated bits in. Has anyone out there used them as rafters and how did it go?
3).If I stick with the same type of timber are there any restrictions on the number of noggins I could use in a roof to make it all straight?
4).If some of the rafters also bend in the vertical plane by 20mm or so will this be noticeable on the final roof finish or will I need to adjust the tile battens to straighten it all up?
Any thoughts would be greatly appreciated.
The SE's spec asked for C16 stress graded, dry, preservative treated SW timber - which is what I used. I inspected in on the wagon when it arrived, it was nice and straight and dry. I stored it correctly supported and under cover and it's all been installed in the dry ---- so why is it all b****y bent and twisted?
I'm concerned because the next job is the roof which will be constructed from similar C16 timber but 175x47 with a rafter length of 7.2M.
My questions are:----
1).Is there any better grade of timber out there I could use that is guarenteed to be straight?
2).I've had a quick look at engineered timber 'I Beams' but they seem a bit of a faff for the roof which has a few complicated bits in. Has anyone out there used them as rafters and how did it go?
3).If I stick with the same type of timber are there any restrictions on the number of noggins I could use in a roof to make it all straight?
4).If some of the rafters also bend in the vertical plane by 20mm or so will this be noticeable on the final roof finish or will I need to adjust the tile battens to straighten it all up?
Any thoughts would be greatly appreciated.