Strapping required

[John2000]

I have had a timber side extension built. SE has put restraint straps on the drawings. Builder and BCO have said it’s all connected/nailed and not necessary. 

 

I understand that the hurricane ties might be OTT for my area but I still don’t like the idea of the rafters only sitting on the purlins then lower binder/purlin without any connectors. The ceiling  joists are acting as rafters ties but just nailed to the rafters - no bolts or screws. 

 

Should this be beefed up a bit? 
 

Twisted restraint from gable end wall onto rafters and rafter clips on the purlins?

 

plus better connection for rafter to ceiling joists/rafter tie?

 

One side of the roof is normal gable, one side has a gable projection/doghouse front. - hence the rafters pointing into the stud gable end there. 

 

I also think the purlins should be packed out both sides with dry mix in masonry side and  some noggins on timber side to stop twisting. 

 

(Don’t ask about the 4x2 - it’s what the SE spec’d - I asked builder to go with 6x2 but when I got back from work that day all the 4x2 was in) binders and outlines and internal stud walls support them but just another annoyance.

 

Many thanks

 

[Redbeard]

Rather than metal straps we use to use (for a range of timber buildings) 50 x 50 sticks fixed to the face of the bottom beam and purlins and then screwed sideways into the rafters. Don't have a pic to hand.

[SimonD]

48 minutes ago, John2000 said:

I have had a timber side extension built. SE has put restraint straps on the drawings. Builder and BCO have said it’s all connected/nailed and not necessary. 

 

Personally, I would go with what the SE suggests, even if it seems over kill. We have uplift restraint straps throughout the house and they take a few seconds to fit with a metal connector nailer and the traps themselves are cheap as chips by the box full.

[John2000]

Thank you. Yeah that’s my view. It’s the restraint straps I was unsure of. The uplift/hurricane ties I’d go with as it’s a bit windy here and why not. The he’s mentioned twisted restraint straps - I’m assuming from gable end to joists… at 3/4 points along joists and mid height of verge. My head just thinks about the rafters spreading and pushing out. They’re birdsmouthed and nailed to purlin and to wall plate. Nailed to joists. And I’ve got 400c so plenty of them. Apart from the rafter and CJ spec everything else has been overkill and that’s what the BCO said. I really wasn’t sure on where exactly the twisted restraint straps would go. 

[SimonD]

7 minutes ago, John2000 said:

I really wasn’t sure on where exactly the twisted restraint straps would go. 

 

I'm guessing it's these kinds of straps?

 

 

 

Best to go back to the SE and confirm locations as it doesn't seem entirely clear.

[kandgmitchell]

More like this sort of thing with the short bit nailed to the stud in the gable at mid-point in gable and the long section nailed to the adjacent rafters and a noggin set between them (overall length of strap is 1 or 1.2m) to suit. I guess that the strap will be to the underside of the rafter/noggin rather than the top as shown, since the stud will have stopped short of the top edge of the rafter.

[John2000]

Yes thanks. I think both can be used. Clipping down to the purlins and the long restraints to tie the wall back. Pain as the house is wrapped boarded and wrapped now but would’ve been so much easier as he went round with the nail gun at the time. All I ever hear now is ‘that’ll do’ 

[kandgmitchell]

Given the increase in extreme weather we seem to be getting now, a small amount on extra strapping would be a good investment, but I agree it's not easy to do with air tightness requirements as they are.