I have a roof design to implement when my extension walls are
complete. The design is about 6 purlins running at right-angles to the
roof slope (shallow 12.5 degree pitched roof, more like flat roof
design !), supporting standard-sized roof joists.
On one side (a new wall), the perlins can be build into the inner leaf
and packed as appropriate, which is easy. On the other side (the
existing house wall), I have a choice of a wall plate bolted on
parallel to the roof slope, with either joist ends cut to slot in, or
timber joist hangers from the wall plate. On the other hand, what
about masonry joist hangers which must somehow me positioned and
packed to hold the joists level. I'm also not sure if the purlins
should be angled to the roof slope, or on the horizontal - this may
depend on the method of attachment.
What's the best idea (the plans are vague on this point) ?
Cheers,
Simon.