Valley Beam Angle 45 degree?

[chirpychippy]

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Hello all, I have moved this post from the wrong section to this section and the above link has the architects drawings which relate to my question.

I am pitching a new 45 degree pitch roof into an existing 37 degree pitched roof. Wrightwoodwork explained the method of using lay boards, however this method I am familiar with but thank you all the same.

Once you have looked at the drawings it will be much clearer than myself trying to explain it in my mumbo jumbo way. The drawing shows the Valley beams go in at 45 degrees from the ridge to their respective corners, but I don't think they will and in which lays my confusion. To my mind, the valley beam intersecting a 45 degree pitch and 37 degree pitch roof would not go in at 45 degrees, I might be overthinking this one, but any help would be gratefully received.

 

[chirpychippy]

Its the new Bay I am referring to, thank you.

 

[catlad]

Once you have built the framework for the new bay you could put a layboard so the valley rafters have something to land on.

 

[chirpychippy]

Thanks cat lad but its not having lay boards its having valley hips,!

 

[noseall]

It will be a trial and error job for the valley rafter. But instead of bisecting the jacks at 45 degrees it will have to be slightly off because of the difference in pitch.

Yo Catlad, look at it as an inverted hip rafter.

Why can't the bay be the same pitch as the main roof?

 

[chirpychippy]

Its all to do with the existing collar height and the line of the bottom of the triangular window lining up with the bottom of the soffit and the bay being 2300mm wide all makes a 45 degree pitch, all coupled with an anal customer, it has to be just so.

It all adds up to a pain in the rrrrrrrr s, thanks noseall.

 

[noseall]

It looks as though you have room for two sets of common rafters before getting to the valley rafter and the jacks.

I would pitch up my two commons and insert the ridge board. The other end of the ridge board can be propped on batten.

Where ever that ridge board bisects the main roof along the very top edge, is where your valley rafter finishes at the high end.

The valley rafter at the low end is positioned so that when you drop a straight edge across the top line of the rafters on both the bay and the main roof rafters, it is where they bisect.

You biggest headache is measuring and using a bevel to get the angles. As I said earlier, instead of your compound cut having a 45 degree cut, it will be summat a little more acute.

Because the main roof is a shallower pitch compared the bay roof, the whole valley section will seem elongated. Had it been t'uther way around, then the valley section would have appeared stubby or stunted.

 

[catlad]

I thought the common rafters were coming through the bay and you could lay a board to catch the valley rafters. looks tricky have fun.

 

[chirpychippy]

Seems a logical way of doing it Nose all cheers, but its still going to be a bar steward, I am not concerned cat lad, I've got a taxi on standby to pick up a chap from staffs if it all goes wrong