Splicing existing ridge beam to new on Hip to Gable loft conversion

[Elthrin]

I am doing a Hip to Gable loft conversion where the main part of the loft has oreviously been converted. I need to splice and extra 4m ridge onto the existing ridge but I am not able to find any sensible information on how to best achive this. Building control suggested Butt joint them with two metal plates either side and M12 bolts through the whole sandwich.

My concern is that I will be left with a section of Ridge that is now solid steal and I will noolonger be able to attach the rafters. Or I will only be able to have a 35cm long plate, which oes not sound like enough.

What methods have other people used.

 

[noseall]

The ridge will be held in place by the rafters. Butt them together as per BC and use plates that fit between the rafter spacings.

 

[tony1851]

Is the original ridge steel or timber?

If you are joining steel to steel, you would do a traditional splice with top and bottom plates, plus web plate(s)
In that case, as the bending moment would probably be at its maximum where the splice is, it would need to be designed, with friction-grip bolts.

If the existing ridge is timber, you will have difficulty joining it to new steel.

 

[noseall]

Oh, is this a steel beam?

 

[catlad]

I would use some plywood to splint them together and if the building inspector wants more you could use a piece of 6x1" across the top of the rafters instead of the top baton.

 

[tony1851]

I'm not sure now; on re-reading the OP, it looks like it could be a timber beam.

If he's trying to join timber-to-timber that will be a problem, particularly if the joint is anywhere near mid-span. And if it's a long span (5-6m?) deflection will also be an issue.

We always use steel ridges when doing hip-to-gables.

 

[^woody^]

Not many existing hipped roofs have a steel ridge.

In real life, the ridge is a non structural ridge board not a beam, and its just jointed at a point in between two rafters.

If the OP is inserting a ridge beam as part of the conversion, then that should not make any difference to the existing ridge.

 

[noseall]

Not many existing hipped roofs have a steel ridge.

In real life, the ridge is a non structural ridge board not a beam, and its just jointed at a point in between two rafters.

These were my thoughts Woodruff. I'm a tad confused by the steel elements here.

 

[tony1851]

Not many existing hipped roofs have a steel ridge.

In real life, the ridge is a non structural ridge board not a beam, and its just jointed at a point in between two rafters.

It depends; if the conversion is a hip-to-gable with a rear flat roof dormer as well, then the ridge board idea doesn't work. In that case, a proper- designed- beam at ridge level would be needed as the triangulation is lost.
OP doesn't make it clear what's going on, though.