Replies

1. 
   calvin | Jun 15, 2012 05:44pm | #1

   John

   I've only used a subfascia, but no telling what was done at your house.

   However, what's the soffit made of?

   Vinyl?  you can probably pull out a pc or maybe press around on it to figure out what's what.

   or

   take a thin drill bit (but long enough to drill through the cedar and a 2x) -drill through  the face of the cedar-if it goes in 2-1/4 to 2-1/2 inches b/4 it meets no resistance, you can probably pretty much assume a 2x material as a backer to the cedar. 

1. 
   johncros | Jun 15, 2012 06:36pm | #2

   subfacia?

   I have been trying to read articles online to try to find out how homes are constructed and I had not run across the term sub-facia.   Your idea about drilling a small test hole is a good one.  I should thought about that. 

   The soffet under the eves seems to be plywood or something with a wood veneer layer.  My longest ladder is a 24' extension and that is not high enough for me to reach the lowest point of the eves.  I have to work from the roof down or rent a 32'er

   Thanks. 

1. 
   calvin | Jun 16, 2012 07:01am | #3

   Well.............

   Sub fascia is what we called the backer to a finish fascia.  We framed with one all the time-could be wrapped with aluminum or a finished wood applied.  It tied all the rafter tails together at the eaves..  In your case, running up the rake of the roof, it would more correct for me to  have called it the fly rafter.

   Blocking (lookouts) would have been installed between the fly rafter and the "ribbon board"-the nailer up the gable wall parallel to that fly rafter.  The fly, ribbon and the blocking would give you nailing surface for a continuous wood soffit.

   Regional nomenclature and who trained us often gives different names to the same thing.

   You could also look for a nailing pattern on the fascia and/or the soffit to maybe figure out what's in there.  A subfascia or fly rafter would allow rampant nailing (not into the ends of a more repeatable blocking or lookouts).

   Be safe and while working on your house, especially on the roof-never back up.  Get the right tools and use them properly to limit the chance for an accident.

2. 
   DanH | Jun 16, 2012 07:59am | #5

   DO NOT attempt to do this from the roof.  You'd need to hang over the edge both while installing the mounts and while working the mast into place, and that's just scary.

   If you don't have a proper ladder (or, better, scaffolding), then install a rooftop tripod instead.  Much more secure, far easier to service (eg, when lightning takes out the preamp), and it will not cause significant roof damage if done correctly.

2. 
   DanH | Jun 16, 2012 07:51am | #4

   If this is a house built with roof trusses the gable end almost certainly is backed up by a special gable-end truss that is framed with vertical 2x4s laid flat, at perhaps 2-foot spacing.

   This truss is generally constructed in a way that the top of it is 3.5" (or maybe 5.5") below the top surface of the standard trusses ("drop chord"), and then a ladder-like framework crosses over the the top of this truss, attaches to the side of the inboard truss on one side, and canitlevers out on the other side.  On the outer edge of the framework is your sub-fascia/barge rafter.

   View Image

   I would generally not recommend tying the top of an antenna mast support to the barge rafter, unless you pull the soffit and reenforce the connections.  The barge rafter is probably just straight nailed to the ends of the "ladder rungs" (lookouts) and wind forces would tend to work it loose.  (Note that there is no guarantee that there is a lookout at the peak -- the top-most lookouts may be several inches down from the peak.)