I seem to be doing more roof`s latley. is there a rule of thumb for droping the birds mouth on the hip rafter. I know the longer the run the more you have to drop it, but info on this topic is hard to find..
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
The "She Build" initiative is empowering women in Seattle, WA by ensuring they have safe, healthy homes.
Featured Video
How to Install Cable Rail Around Wood-Post CornersHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
Have a look at this current thread. Might be what you need.
http://forums.taunton.com/tp-breaktime/messages?msg=89089.1
You need to shorten the hip rafter by a length equal to one half the length of a line drawn across the hip rafter at 45 degrees. For a hip that is 1 1/2 inches wide this equals 1 1/16 of an inch.
This information is in any carpentry textbook used at colleges or apprenticeship programs.
Have a good day
CLiffy
The amount of the drop is not based on the run but rather the width of the hip as well as the pitch. Check out Joe's drawing in the other hip thread.
John
Edited 4/26/2007 8:11 pm ET by kpatrix
For bastard Hips created by the intersections of unequal roof slopes it's also best to offset the Hip rafter in proportion to the plan angles. This locates the Hip rafter in relation to the where the roof slopes would intersect or "plane in" if the Hip rafter were backed.
Proportional Hip Offset and Hip Drop
Example Hip Offset-Drop Calculations
Hip Drop for Offset Hip Rafter ... the animated version : the blue line labelled "tan Hip-Valley Pitch Angle" is the "Hip Drop".
Joe Bartok
Edited 4/28/2007 10:34 am ET by JoeBartok