Flat roof lateral restraint

[Peter500]

I'm trying to work out how to provide lateral restraint for the angled wall on the left (if it's required at all). I'm using metal web joists and it's only single storey.

On the TRA site (page 13 at in https://www.tra.org.uk/wp-content/uploads/dlm_uploads/tra_metal_joists__single_final.pdf), it shows a metal strap going into the blocks. However, if I did this then the 90 degree bend would stick out in the cavity and not sit flush against the wall. I don't know whether anybody else has had a similar situation or knows how to do it?

The roof designer pointed me to building control and build control said it's up to the principle designer . Maybe it's a structural engineer question? My gut feeling is that the joists will provide some lateral restraint as they are built into the wall, but would it be enough?

Also, are lateral restraint straps required on the shorter walls too e.g. the 2480 wall that runs parallel to the joists?

 

[23vc]

Those angled straps can be fairly easily bent to other angles greater or less than 90

 

[Peter500]

Those angled straps can be fairly easily bent to other angles greater or less than 90

I did suggest that but the roof designer person advised against it because it may weaken them. Is this the done thing?

 

[catlad]

A few noggins will help as well.

 

[Peter500]

A few noggins will help as well.

I think you mean a single piece of timber going through the joists? As they are metal web the timber can go straight through them.

 

[catlad]

Or a plywood gusset.

 

[Peter500]

It's very hard to see lateral restraint on flat roofs on youtube etc. Is lateral restraint always required? Would my brick corners and steel beam act as lateral restraint? i.e. Can the restraint start 2m from the corners?

 

[^woody^]

Not necessary for a single storey without a gable, just the twisted hold down straps will do on those three joists on splayed wall.