Existing rafters for loft conversion

[jackofairbrother]

Hi,

Thanks for all your previous help as I normally always seem to find the answers to any other enquiry’s I have.

Renovating a house atm and the overall build is around 25/30mm out to one side (over around 10m), the brickwork, ceiling joists, wall plate, rafters etc. No cracks on the brickwork, walls are pretty plumb all round, so guessing poor workmanship.

Anyway. I’ll be doing a loft conversion with new large rear dormer so will have a new ridge beam (Flitch beam)
Obviously this will be set level.

House is a building site, was going to take down the old plasterboard ceiling, cut out old ceiling joists after supporting. Then I can put the floor joists in level to tie to the rafters.

The new 8x2 floor joists are to be run on the existing wall plate which currently runs out.
The rear of the house, most of the rafters etc will come off and new plate can be set level or joists packed up and match the new level ridge beam.

So question is, on the front of the house, would you leave the existing wall plate and rafters in. Just see this is going to fall short of the new ridge a few mm every time up to 30mm at one end.Is that a problem?

Or Fix new timbers to the existing to extend them? Or would it be best to take the whole roof and redo in 6x2 to account for the insulation etc,

Thanks in advance!

 

[catlad]

If its a building site then use new rafters. It will be faster and better in the long run.