Replies

1. 
   kpatrix | Feb 11, 2008 04:56am | #1

   How is the slope on the eyebrow dormer going to be parallel to the the existing. It needs to be a shallower slope so that they will intercept.

1. 
   seadrifter | Feb 12, 2008 02:35am | #2

   You are correct on this is their a certain formula to follow or does one just uses the eye to gauge how it looks. Look forward to your reply.Brian

1. 
   kpatrix | Feb 13, 2008 08:33am | #3

   With a 12/12 I think the best look is going to be a 5/12. It all depends on the main ridge height and the height of the dormer. It may have to be a 2. It could even be horizontal. The horizontal is the easiest to do. All the lofting points can be calculated with a CM pro fairly easily. With a good understanding of math and how the lofting works, the measurements can be accurately transfered for easy valley and sheathing cuts.There was a good thread about this on JLC

1. 
   Hazlett | Feb 13, 2008 02:45pm | #4

    FHB------- march' 91 had an article on this, I think.-stumbled on it by accident yesterday---haven't read it  yet.( I am slowly going through a collection of back issues,

   stephen

1. 
   JoeBartok | Feb 13, 2008 06:43pm | #5

   Purlin or Square Hung Fascia intersects Main Roof Calculator  ... there are links below the calculator that show how to adjust the inputs for purlins following a circular or elliptical arch, and if the dormer roof is sloped.

   Development of Circular or Elliptical Dormer intersects Main Roof ... layout of the sheathing.Joe Bartok

2. 
   Dave10990 | Feb 14, 2008 05:49am | #6

   We did an eyebrow window two years ago, and it came out great.  On a 12" pitch roof, it worked out to be about a 5"pitch.  We took the plane of the main roof, and "swelled" the eyebrow out of it.

   We used two layers of 3/4" plywood, glued and srewed, to make the rafters. The radius remaining the same, but the depth of the radius (chord?) decreased until we intersected the main roof a bit below the ridge.  To clarify, the rafters of the eyebrow where parallel to the ridge, at right angles to the common rafters.

   They fit between the doubles on either side of the opening.

   We sheathed with a double layer of 3/8" wiggle board, the second layer breaking the seams of the first layer.To form compound curves with the sheathing, we had to make darts, or relief cuts, to make it lay flat.  This was also glued and srewed.

   There isn't a "quick" way to frame it, because of all the effort it is to make the curves fair.  Ours was a true eyebrow, and it was part of the finished room.

   It became a topic of conversation in my town, as it was on a busy road, and drew a lot of attention.

   It was roofed with cedar shakes, and we made the coursing run up and over the roof, and didn't treat the eyebrow as a seperate roof, with a valley around it.

   The fascia was made out of 1x12, with a moulded crown, which we laminated and routed on site.

   It took two men about four days to build it and have it prepped for roofing.