Replies

1. 
   92588 | Nov 24, 2003 01:48am | #1

   get larry hahns? very efficient carpenter book. lots of good tips with your answer

2. 
   dIrishInMe | Nov 24, 2003 02:08am | #2

   Actually, what is happening is the the center line of the hip rafter is at the correct height, but the edges are protruding up above your roof plane.  You need to either drop the hip rafter a small amount, or cut back bevels on the top of the hip rafter along it's length.   Almost no one cuts back bevels.

   The way you drop the hip rafter is simply by cutting the bridsmouth a little deeper.  In other words, the plumb cut of the birds mouth is a little longer.  How much... here are the hip drops numbers for a few common of roof pitches.

   6:12   1/4"
   8:12   3/8"
   10:12 1/2"
   12:12 5/8"

   If you prefer to cut the dual bevels on the top of the hip, let me know and I'll go look up what the angles are.  They are different depending on the roof pitch. 

   Matt
3. 
   goldhiller | Nov 24, 2003 02:38am | #3

   Here's one way of determining the right amount of drop or backing with the familiar and always available framing square.

   Example in illustration is for an 8/12 pitch.

   Knowledge is power, but only if applied in a timely fashion.
4. 
   Timuhler | Nov 24, 2003 02:49am | #4

   Hammerelbow,

   The previous post was correct.  If you are using 2x material and the roof is regular (all the pitches are the same and the hip is bisecting a 90° corner), you draw your plumb line at the the length you want, then measure 3/4" perpendicular to that line on the uphill side and draw a new plumbline, with the same heelstand or HAP and the hip will plane perfectly.

   Here is a picture explaining this.  Sorry for the quality.

5. 
   Framer | Nov 24, 2003 03:16am | #5

   You have to adjust the H.A.P. cut (Height above Plate) or HEEL cut in order to plane in with the top of the Common Rafter H.A.P. cut at the plate line. Or you can bevel the hip which you don't need to to.

   You will see the reason why in my drawing that you have to drop the hip or adjust the hip to plane in.

   Whe you mark the length of your hip you are marking it to the outside corner of the top plate. Since the hip is at 45°, if you mark your H.A.P. cut at the line of your hip length you will see that the line of the H.A.P. wil be 3/4" (1/2 thickness of hip) will not be sitting on the plate where it should be the same H.A.P. as the Common H.A.P. cut.

   You will see that it creates a little  Triangle, a Run and Rise. That rise would be the amount of the Hip Drop or if you didn't cut that H.A.P. cut from the right mark, that would be the amount that the hip would be sitting higher then then the Common H.A.P. cut therefot it wouldn't Plane in with the Common Rafter and there would be a hump at the corner where the hip sits.

   Valleys you don't do anything, you mark the length and make the H.A.P. cut the same as the Common H.A.P. cut.

   Joe Carola

6. 
   Joe_Fusco | Nov 24, 2003 04:03am | #6

   hammerelbow,

   These links should help.

   Finding the hip drop.

   Angles for 12 common pitches.

   View Image
   

   
   

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   Edited 11/23/2003 8:05:17 PM ET by Resurrected