Flat to pitched roof

[Taz9126]

Hi
I'm looking at converting flat to pitched .
Roof has wingspan on top of joists , so have a couple of questions .
Once this removed will I have to run a joist at 90' along front edge on top of existing joints to act as wall plate to take the birdsmouth rafters ?
Also how will I secure the other end where existing rafters of house roof meet the ridge board ? As these new rafters will have to be lower than existing ridge board as I will be looking at roof tiles
Thanks in advance

 

[noseall]

Yes, you will need a wall plate and it will require strapping down.

If this new roof lands onto an existing roof then you will have to construct a valley either with pre-made trusses or via a ridge board, lay boards and jack rafters.

 

[Taz9126]

Hi noseall
Thank you for your reply
I've done rough sketch (Ha ha no artist)
The existing ceiling joists are obviously the base of the former roof but with decking removed .
Can the wall plate be screwed or nailed to existing joists or doesn't it not conform to BR and needs to be strapped down ?
The birds mouth will sit on the wall plate but unsure of how the other end (ridge end)
Will be fixed or wot too ?
As I kno it's not deep enough to secure proposed rafters too
Thanks in advance