purlin and ridge board extending

[magico]

Hi can someone help me out here please.
I'm doing an 1st floor extension over a ground floor garage conversion. All foundations checks planning sorted ect...the house has a hip roof and converting to a gable end. How do you extend the purlins and ridge board. The purlins as they stand are supported on supporting walls in the loft. I've googled and seen scarf joints and other people say butt join and splice. And also the plans say to use 4x2 for roof spars when the origional are 3x2. Any info appreciated. Any 1 know of any reading material I could download or buy to help me out here.
Thanks muchly
Mark

 

[freddiemercurystwin]

Can you not use pre-made trusses?

 

[magico]

no want the loft space open

 

[Ian H]

I'm pretty sure you would need a structural engineer to design it for you.

Your house sounds just like mine and our ridge board is like a piece of skirting board. The new one will be steel and effectively make the house hip to gable, with a new hipped end over the extension.

We used a structural engineer from Manchester and myself and Rochdale Council were very happy with his work.

 

[magico]

no its a semi detached with a hip now. with attached garage, which is to built over with a gable end....doing away with any hip

 

[chappers]

the ridge board doesn't really need joining but you could just nail a wooden plate over the joint.
The purlin may need to be designed depending on it's length or might not be necessary depending on the run of the roof.