Top hung posi joist - nail or screw to wall plate?

[bissoejosh]

Joists are here and dropped in at 400mm centes

 

I'm thinking skew nail the top chord to the wall plate but would welcome any suggestions. For the most they are 97 or 122mm wide, would top down screws give a better fix? Can't find anything specific in the layout drawing or manufacturer installation details.

Edited April 24, 2018 by bissoejosh
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[Mr Punter]

It may be best to ask the supplier / manufacturer / designer as it should be their responsibility for the design / spec.

[PeterW]

Make sure you pack the bottom chord tight to the wall plate otherwise it will bounce and flex. 

[Crofter]

The usual rule of thumb is to use screws in tension and nails in shear.

[bissoejosh]

9 hours ago, Mr Punter said:

It may be best to ask the supplier / manufacturer / designer as it should be their responsibility for the design / spec.

 

They suggested skew nailing but didn't have any strict requirements as such. 

7 hours ago, PeterW said:

Make sure you pack the bottom chord tight to the wall plate otherwise it will bounce and flex. 

Yes, I was planning to do this as there is a gap at both ends, not huge and within the design but I'd like it as firm as possible. Would timber wedges do or something more substantial?

 

34 minutes ago, Crofter said:

The usual rule of thumb is to use screws in tension and nails in shear.

This was how I understood it, but are the top down fixings technically in shear as the joist moves laterally when it flexes or in tension as they fix it down to the wall plate?

 

I think the safest bet is probably to skew nail each one.

[PeterW]

5 minutes ago, bissoejosh said:

Would timber wedges do or something more substantial?

 Timber wedges from the top down if possibly and a good squirt of D4 glue on both sides for good measure. 

[bissoejosh]

3 minutes ago, PeterW said:

 Timber wedges from the top down if possibly and a good squirt of D4 glue on both sides for good measure. 

 

Ideal, I can certainly sort something similar tomorrow - thanks.