Roof and doormer at different pitches creating valley in wrong position - how to resolve

[OscarWilliams]

First time pitching a roof and mistakenly made the doormer (32 deg pitch) a different pitch to the main roof (46 deg pitch) in order to increase headroom, the result of this the two pitches / slopes dont intersect at 45 deg, creating a valley which is slightly L shaped rather than v shaped, which in turn means I cant get my valley tiles to sit properly. Is there a standard solution to this problem?...perhaps use a dry valley with lead work at the bottom to direct flow onto main roof?

 

Have tried  putting the valley timber at 45 but this means the jack rafters are suddenly the wrong pitch.

 

Changing the pitch of the doormer is not an option at this stage...

 

Any advice appreciated,

 

Cheers

 

Oscar

Edited October 3, 2020 by OscarWilliams

[PeterW]

Lead valley is your friend there - only issue will be the Jack rafter isn’t high enough to sit valley boards on so you may need to pack it. 
 

 

[tonyshouse]

Equalise distances . Ridge in first then common rafters to the front of the gable then the valley rafter should run from the point where the ridge intersects the main pitch to about where your hand is (where the top of two rafter Meet, one from each pitch 

[Hobbiniho]

yeh agreed, valley rafter is in completely the wrong place, you have 2 options move the valley rafter into the correct place for the 2 different pitches you have, or completely reframe the dormer, you appear to have enough room to do this why did you pick 32 deg for the dormer?, you also wont get your valley tiles to work unless you completely reframe the dormer to have the same pitch as the main roof

[tonyshouse]

Valley tiles are a bit forgiving and will cope with 8 degrees difference in pitch, after that they will start to kick up tiles. 
 

I like grp valley formers but valley tiles are best 

[OscarWilliams]

12 hours ago, tonyshouse said:

Equalise distances . Ridge in first then common rafters to the front of the gable then the valley rafter should run from the point where the ridge intersects the main pitch to about where your hand is (where the top of two rafter Meet, one from each pitch 

We tried putting the end of the valley timber at the begining of the doormer wall plate (where it should be) but this then kicks the jack rafters up because the two angles are different. The intersection point (where the doormer and main roof battens converge) between the two angles is constant and only occurs where they are currently...hence I don't think it can be solved without re pitching the doormer. Starting to think a grp valley is the only way forward...!

[Mr Punter]

I agree that GRP is probably best.  I don't think the valley tiles will sit right with the 2 different pitches.  With no experience of pitching a roof you are attempting something a bit tricky.  The valley rafter looks a bit sad but once the other rafters and valley boards are in it should be OK.

[the_r_sole]

this is a strange one - it's definitely not framed right but I just can't figure out exactly why/how!

Get yourself a copy of the lead manual and you'll be able to flash anything ever! I can only think of one job where we've specified valley tiles before - it's not uncommon for the pitch on a dormer to differ from the main roof at all