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Matt:
If you’re doing any amount of “split pitch” roofs, (even one, is any amount) you might like to try “Rafterman ” It’s a program that I surfed across looking for roof info on the web a couple of years ago. The writer of the program is a framer in Texas who wrote and used the program for many years and is still using it. You could view it for yourself at: http://rowell.pair.com/raftweb.htm, or try a search for “Rafterman on the Web”. I’ve bought it used it and like it. You can download trial version, I cut a house we did last year and it worked like a charm.
Hey Tommy B. it was my post to you about the Roof Framers Bible with Ken’s nod of approval, by the way.
Just had to clear this up in case the IRS wants to discount my “charitable donation” status.
Remember, “If you want to test your memory, try to remember what you were worrying about one year ago today.”
Montana Mike
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Multi-slope hip roof:
Or: The way the architect drew it, the way engineer supported it, but how does the carpenter make it work?
This one might make you all think a bit - or maybe not….
To simplify things a bit, for explanation purposes, let's say that the house footprint is a simple rectangle 40' x 60'. The front and back dimensions are the 60' one. The slope of the front and back roofs are 8:12. The side roof surfaces have a slope of 12:12.
Part 1, The rafters:
A) What are the angles of the plumb and seat (level) cuts on the hip rafters?
B) What are the angles of the plumb and seat (level) cuts on the front & back roof jack rafters? What is the second angle of the compound cut at the top of these jack rafters?
C) What are the angles of the plumb and seat cuts (level) cuts on the side roof jack rafters? What is the second angle of the compound cut at the top of these jack rafters?
All replies are greatly appreciated. FYI, this is the real thing for me - it's not a hypothetical situation. PS: know any *good* framers who in the Raleigh NC area?
*Matt1) The plumb cut angle for hip or valley rafters is 29 degrees. If you use a framing square, you could use 12 3/16" on the tongue and 22" on the body. The tongue gives the plumb cut and the body gives the level cut. ( I only use the number 17 on the body for single pitch roofs, but if you prefer, use 9 7/16" on the tongue and 17" on the body )2) The plumb and level cuts for the common rafters and the jack rafters are the same as always. Just use 8" on the tongue and 12" on the body to cut the 8/12 rafters ( or 33 3/4 degrees), and 12" on both tongue and body to cut the 12/12 rafters ( or 45 degrees). What does change is the circular saw bevel to make the cheek cuts on the jack rafters. For the 8/12 jacks, the bevel is 56 1/4 degrees. For the 12/12 rafters, the bevel is 33 3/4 degrees. ( The two bevels will always add up to 90 degrees )Use these same angles to make the cheek cuts at the tops of the hip rafters. ( Instead of 45 degrees )Here is some additional information that you may find useful:Jack rafter "step" for rafters 16" on center:8/12 jacks = 28 7/8" 12/12 jacks = 15 1/16"Jack rafter "step" for rafters 24" on center:8/12 jacks = 43 1/4" 12/12 jacks = 22 5/8"The "backing bevels" if you wish to cut them on the hip rafters are 18 degrees on the 8/12 side and 36 degrees ( not 37 degrees as in Roof Framer's Bible) on the 12/12 side. This will allow both sets of jack rafters to plane in with the hip rafter.
*Ken,Glad to see your alive....Got an idea....FramingMath.com....or better yet...CuttingRoofs.comJ
*Per Ken's suggestion in a previous thread I purchased The Roof Framers Bible on line and Barnes and Noble, had it in three days. I think it will help you. I will never want for roof framing info again.I hear Raliegh is booming, could I come down there and make any money, not as an employee, but as a sub or gc? Not afraid to go where demand is greatest,Tom
*Man, you guys knocked that one out in a hurry! Thanks loads! The first thing that I got out of your answers, was that the plumb and seat cuts on the jacks are standard, just the bevel changes with the multi-sloped configuration - which I should have realized. I think I never really got past trying to figure the hip rafter.Ken:I knew about using 17 for the run on the single pitched hip rafter, but how did you arrive at the '12 3/16" on the tongue and 22" on the body' part for the hip rafter?When you say the 'Jack rafter "step" for rafters 16" on center', does this mean, the length at which each subsequent jack rafter increases?Tommy:Raleigh is wide open for the construction trades. If any GC or sub is not very busy, there's something wrong there. Not sure how it pays down here compaired to what you are used to. Ask me a specific question and I'll give you an answer. I gotta go find out about the book you suggest.All:Please look for my subsequent post, "Framing 211 - multi-slope hip roof, part 2. It deals with maintaining a uniform soffit widths on this same house.
*Matt:If you’re doing any amount of "split pitch" roofs, (even one, is any amount) you might like to try "Rafterman " It’s a program that I surfed across looking for roof info on the web a couple of years ago. The writer of the program is a framer in Texas who wrote and used the program for many years and is still using it. You could view it for yourself at: http://rowell.pair.com/raftweb.htm, or try a search for "Rafterman on the Web". I’ve bought it used it and like it. You can download trial version, I cut a house we did last year and it worked like a charm. Hey Tommy B. it was my post to you about the Roof Framers Bible with Ken’s nod of approval, by the way.Just had to clear this up in case the IRS wants to discount my "charitable donation" status. Remember, "If you want to test your memory, try to remember what you were worrying about one year ago today."Montana Mike
*Mike, I am so very sorry that I did not credit you with your advice. "Mike gave me the idea for getting the Roof Framer's Bible everyone!" That reminds me of a quote that I think is true for the most part, "Gratitude is the least deeply felt of all human emotions". I am not sure who gets credit for that. Tom