valley/hip rafters

[philblack]

Hi all, what is the plumb cut angle of a valley rafter when the pitch of the roof is 35 degrees and is there a formula to work this out on any size pitch? Thanks

[Clanad]

The plumb cut is the reciprocal from 90 of the pitch of the roof. So if the roof pitch is 35 degrees the ridge angle is 55 degrees (90-35)...

[stanwilcock]

valley rafter not common rafter

[AlBags]

If a standard valley of 45 deg. then the plumb cut will still be 55 deg at 45 deg to the valley.
Easy if you use a Compound Mitre Saw.
Try a short piece first and leave set for the rest.

[buildersmate]

I reckon the answer is a 27 degrees, if we are talking about the angle of the valley rafter to the horizontal. Or 63 degrees between the plumb and this rafter. I derive this from calculating the angle whose tangent equlas (tan35.cos45). I needed trig tables to work this out.
If we are talking about the angle formed along the PLANE of the roof, between the ridge and the cut-line of the valley, that is obviously different.
No, I'm not a builder, but an Engineer.

[xraanswerban]

if you are constructing a roof the best way to find the angle of the valley rafter plumb cut is to mark a plumb line on the hip rafter with the aid of a spirit level and then use a bevel to find the angle. easy! [joiner for 53yrs]

[rivalryan]

Hi all, this is quite simokle to work out it goes as follows:

s - slope of adjacent roof in your case 35 degrees
d- the angle in plan view between the valley and the adjacent ridge (always 45 degrees unless irregular hip)

formula : TAN S X SIN D = hip or valley plumb cut / slope

enter 35
press tan
= 0.700208
x
45 sine
=0.707107

0.700208 x 0.7071707 + 0.495121
now press inv tan to = 26.34 rounded to 26 degrees

I would suggest buying a framing square or quick square to save you having to work out these angles.

Im a roofing carpenter with over 10 years expirience in the trade. hope this helps