gable overhang

[jdhen]

Can I get some opinions- pros and cons- of the various options available to frame the gable overhang?
I was going to use lookouts but I fear that they will get in the way of the airspace between the end and first rafters.  I've also been reading a bit about omitting end rafters and framing the gable end with a 12/12 top plate to rest the ladder lookout on ( I'm guessing I could cut holes in these to facilitate air movement?)
I'm leaving the ridge board plenty of overhang to support one end and I will likely use 2x subfasia.  I plan on leaving the eaves open and will use either carr siding or some sort of plywood/engineered ply that has ridges to mimic tongue and groove over the exposed areas.
Rafters are 2x10 with tails cut down to 2x6 at the overhang and the fly rafter will be 2x6.
Anyway, if I could get an idea what others have done, that would be great.
I'm going to start placing rafters today but leaving the end ones out until I hear back from you all.
Thanks!

[jdhen]

I forgot to add that the overhang will be 12-16 inches.

[Redoverfarm]

jdhen They are not really hard to do.  Here is some discussion about them on another post.  If they are unclear just send me a PM or E-mail and I will try to further explain.  

As far as the ventilation that can be solved by drilling a series of holes through the last rafter on the house to allow it to travel from the false rafter bay over into the last bay of the house.  Generally I don't think these are vented as there is no heated space below them which leads to condensation issues.  

I generally make the overhang to work out with my material (4X8) sheets which would be shy of 12 or 16". The reason I say "shy" is that if you cut exactly 12 or 16" the last sheet will be short by the saw kerf from the previous cuts.  If you sister a 2X2" or 2X4" on the outside bottom of your last rafter and your fly rafter the same demensions to be level with those it will give you a good level nailing surface to attach the soffit material.  If using 4' wide material put a couple lookouts to nail at least every 24" and at 48" where the sheet material will meet.

http://countryplans.com/smf/index.php?topic=6980.msg93014#msg93014

There is some more discussion either proceeding or following this post on the subject.

[ScottA]

You could do something like this and omit the lookouts altogether. Would be in keeping with the style roof you are doing too.


This would need to be a structural knee brace or corbel but with only 12 or 16" it wouldn't take much.

[davidj]

On our 20x30, I've got 18" overhang at the eaves.   The rafters are 2x12, with the tails and barge rafter ripped down to nominal 2x9 (my inspector didn't want me taking away more than 25% at the birds mouth, so this was the smallest I could do).Per the drawings, I've got 2x4 lookouts (lying flat) every 2', with 2x6's wedged in underneath (forming a "T" in cross section).  The 2x4's run back to the previous rafter but the 2x6's are just between the end rafter and the barge rafter.  This is all to provide a bit more strength, I guess, due to the 100psf snow load.

Cutting the 28 rectangular notches in the end rafters for the 2x4 lookouts whilst on scaffolding and ladders involved eating a lot of sawdust - it took me pretty much a whole morning and wasn't fun!  Putting in the actual 2x4's was more pleasant if time consuming, but hanging the barge rafters was a pain (I guess it will be either way).  The plan is to attach the 2x6 part of the lookout as the siding goes on so I don't have to try and trim around them - that's not happened yet.  With 11.25" for insulation and only 1.5" of lookout in the way I think the ventilation problem's gonna be solved by just being slightly light on the fiberglass at the ends.

On the garage I used a dropped (site-built) truss on the ends and missed the end rafter, so the ladder was full-depth of the 2x6 rafters (no insulation on this building).  This results in a lot of blocking and was also a bit fiddly with the two non-standard trusses.  With the exception of the sawdust consumption, I don't think the approach was a whole bunch better.

Either way, if you're an amateur like me doing the eaves takes way longer than you think it should, even if you think it'll take a long time!

P.S. I second that recommendation about thinking of sheet sizes - my 33' x 16' 4" roof wasted a whole bunch of plywood (or, from a positive perspective, was a good way of generating the material for a temporary deck and my neighbors small cabin roof)

[jdhen]

Thanks for the responses.
David, I appreciate you sharing your experience with the two options.  You've helped me realize that the standard lookouts are the best option for me.  I think I will drill the holes to take care of the ventilation as Redoverfarm suggests.  Also, I think I'll pre cut the notches before I install the end rafters so as to avoid the sawdust ingestion.  I believe I'll have enough of that when I plumb the rafter tails!
Scott, I rather like your suggestion and we do plan to use some brackets at the end of each gable eave but my wife says it's too busy for her taste to have that many.  Oh well...

[davidj]

The downside of cutting the notches on the ground is that, if you have sheathing and siding, you have to cut both around the lookout.  I had my sheathing on when I notched them, so only the siding needs to have fiddly cut-outs on the angled edge (although I guess the sheathing cuts can be pretty rough).

Make sure you test the size of the notches with a larger rather than smaller 2x4 - if you test it with dry wood and try and install wet you'll end up having to work hard to get it in, or drag a saw up to make it a 1/32 (or whatever) bigger.  Cutting the notches you want to be maybe 1/16 deeper than the 2x4 (1 9/16") otherwise the "stubble" left ends up pushing them over the top of the rafter.  I also used a very cheap saw blade to do the notches - it had a wider kerf than the nice DeWalt blades I usually use, which resulted in slightly more effort but fewer cuts. Be sure to use safety glasses that cover as much as possible to keep the little chips of wood out of your eyes - I ended up with sore eye all day from one annoying spec of sawdust.

A final useful trick is to cut the miter cut at the top of the barge rafter slightly less sharp than 45 degrees so that, as the wood dries, the gap closes up (miters get more pointy as wood shrinks across the grain).  This also makes the gap wider at the top and closed at the bottom, and the roof flashing typically covers the top anyway.

That all-the-rafters-up celebratory beer is a good one, but you sure have to work for it!

[Redoverfarm]

 jdhen If you have an extra set of hands I found that it is more useful to preassemble the lookouts and the false rafter (faced nailed into the end of the lookouts) then lift it up and place it against the ridge and into the notched out slots that you have.  Then there is no hanging out trying to put the false rafter out onto the ends of the lookouts.  You have a set of clamps once in place just temporary clamp to hold and then end nail the lookouts on the inside face of the third rafter.  Basicly there is no additional weight by doing it this way other than the 32" lookouts (2 will usually suffice).  Then later you can nail your blockings in between at the desired intervals for your soffit.

Well I think I have kicked this dead horse enough. 

[jdhen]

Great suggestions, guys.  Thanks for sharing them!