Roof Spread.

[tony1851]

Not a 'how do I fix this' problem, but a text-book example of roof-spread and what it can do, for those interested.

House is a 1970s detached which is having a higher and wider roof built. Original ceiling formed a 'collar-braced' roof, with raised ties. The ties were re-nailed to the new rafters but the fixings proved inadequate once the weight of the tiles went on.

Fixed now and all good, but the wall will need re-building.

(It wasn't my fault, honest!).

 

[freddiemercurystwin]

It wasn't my fault

Classic tony!

 

[noseall]

I what way were the fixings inadequate? We'd fix ours with screws initially then hit the joints with through bolts after everything is in place and before any weight is added to the structure.

 

[tony1851]

I what way were the fixings inadequate? We'd fix ours with screws initially then hit the joints with through bolts after everything is in place and before any weight is added to the structure.

They initially used the original (rusty) oval nails driven back in. But the new roof is a lot heavier and bent the old nails, so roof pushed out.

This happened last Friday dinner time. Stabilized it over the weekend by tying opposite feet of the rafters with 225x50s bolted with 2 16mm bolts to each rafter.
This week, the bolts were slackened off and the centre of the roof has been pulled back with a ratchet fixed to the ceiling (tiles were removed first to reduce weight) and now back where it should be. All rafters have now been tied with 225x50 - it was going to be ready for a loft conversion anyway so these will do for the new floor. Builders took a gamble, really - these things happen.