Tie new joists to rafters

[Sully872000]

Hi all, what would the best way be to tie new lowered joists to roof rafters in order to prevent roof spread.

[stevei]

You haven't given enough information for an answer. Drawings or photos of your plans for this would be needed.

[ayjay]

You haven't given enough information for an answer. Drawings or photos of your plans for this would be needed.

I can only agree with this, there's just not enough info.

[Sully872000]

See attached picture. As you can see I want to lower the joists in the loft so when I put new joists in, how would the new joists be tied to the rafters to prevent roof spreading and walls pushing out. Someone has suggested plywood gussets attached to new joists and then to rafters. Would this be ok?

[ayjay]

I've never done an alteration like this, but I've done a new build (large extension) that was similar. The spec there was for an Ashlar wall either 1.0m or 1.2m (can't remember) from the inner brickwork and then ties from the Ashlar to the rafter, some of those ties were at angle from the baseplate of the Ashlar wall to the wallplate.

It was a pretty large roof, from memory the rafters were over 7.0m long, and the span was about 8.5m.

I remember being neither impressed with the design nor convinced of it's effectiveness: and I never saw the end of the job as my paymaster went bankrupt, (fortunately he'd left a lot of his tools in my van).

I've just checked google earth and it's still standing 20 years later.

[aeromech3]

Massive angle brackets tying the joists to the wall plate, very unconventional. My ex double garage had the walls pushed out due the rafters were not tied by a few simple joists, the roof had to be supported whilst the walls were rebuilt, thankfully under the NHBC.

[stevei]

Why do you want to lower the ceiling joists? I can't see a way in which you could use the joists in the proposed new position to do the same job as they are now.