where to fix twist ties in our workshop

[Omnibuswoman]

We are almost at the end of building our new workshop, but have not put in any ties to hold the roof to the structure. The rafters are fixed to the top plate with L shaped galvanised plates that are nailed down with about 36 galvanised square twist nails on each side. The top plates (4 of them) are screwed together.

 

I've bought a pack of metal twist ties to nail the rafters directly to the frame, but am now stuck about where to fix them, and whether it is too late to add them. We have already almost finished the external cladding, so it would be difficult to nail these to the outside of the stud frame, but on the inside we have plywood screwed directly onto the studs. Should I fix the ties on top of the ply, and just have them visible? If I try to put the ties underneath the ply I won't be able to screw the ply on properly... 

 

The other option I'm considering is fixing plasterboard on top of the ply for a smooth finish on top of which to paint, because the ply boards have all gone mouldy (see my other thread about mouldy ply!). If I did that, I might be able to hide the ties behind the plasterboard. 

 

All suggestions welcome!

[markc]

If the walls are fixed down and the rafters are secure to wall then ties aren’t really needed.

they are needed on masonry  walls as uplift can be more than the weight of top course of brick or blocks.

pain to let into ply or OSB so I would (if fitting them) plaster board over or make then a feature

Edited November 18, 2021 by markc

[Bonner]

+1, ties not needed. Rafters are fixed to the wall plate which is fixed to studs, all skinned with ply ... it’s not going to blow away!

ps, looks cosy already ?

[Omnibuswoman]

Thank you! Yes I did wonder how strong the wind would need to be to lift this lot up as it is all fixed into the blocks at the base. I’ve got a few metal plates that span the layers of the top plate holding it all together.