Replies

1. 
   Malcolm_Taylor | Feb 15, 2023 04:12pm | #1

   Adam,

   Forgive me if I deal with a related issue, rather than your question - for which I don't have any useful answer, beyond suggesting you maybe use brackets as they often do on Craftsman style houses

   I don't see much of an advantage in your detail to using attached overhangs. They are usually used to maintain continuity between the walls and roof when the sheathing or an adhered WRB is used as the primary air-barrier. You don't have continuity in those elements. I don't see how your detail would change much if you simply had the top chord of the trusses extend out as is typically done - beyond it being much easier to frame.

2. 
   AdamPNW | Feb 15, 2023 04:51pm | #2

   Yes that is something I am still debating too. Ordering the trusses without any overhang would allow continuous ext insulation all the way to the top of the trusses, but this may not be a massive energy saver (this isn’t a passive house so I can probably deal with the energy penalty of thermal bridging at the trusses).
   I’m also trying to prevent wind-washing over the blown-in cellulose by installing the sarking membrane, and the detailing this at the eaves seems more difficult with the top chord extending past the sheathing. Do you have any tips on this detailing?

1. 
   Malcolm_Taylor | Feb 15, 2023 05:49pm | #3

   Adam,

   Part of my preference for extending the trusses to form the overhang is avoiding as much work as possible that needs doing in what is an awkward position on scaffolding or ladder jacks, and making the sequencing of the construction easier.

   I would block between the top chords of the trusses inboard of the wall sheathing. It and the rigid insulation can still extend up to the same level, but would be cut out around those top chords which form the overhang. The sarking membrane would be attached to the top of the blocking.

   You could also stop the 2"x4" furring at the exterior wall and run one horizontally at the rough fascia.

1. 
   AdamPNW | Feb 22, 2023 03:36pm | #5

   Thanks Malcolm, you’ve convinced me to extend the top chords to make the eave overhang. For the rake overhang, my engineer has recommended that I use flat 2x lookouts with blocking. He thinks this will be easier to frame than using vertical 2x6 lookouts (less wood, easier to block). But id like to close in the soffits so that they match at the corners. I’m concerned that the added difficulty of furring down the rake soffit to match the plane of the eave soffit will be more trouble than it’s worth. My thought was that using vertical 2x6 lookouts would be easier overall since the soffits will match planes without any need for furring. Do you have any thoughts on this? I really appreciate the help!
   Adam

   
1. 
   Malcolm_Taylor | Feb 22, 2023 04:07pm | #6

   Adam,

   When I run the soffit boards lengthwise at the eaves I typically maintain that orientation on the rakes. So if was framing the overhangs, I'd use the 2"x4" lookouts for support, attach a 2"x4" rough fascia to the ends, and run a 2"x2" along the exterior wall, and run my (short) soffit boards between the two.

3. 
   seabornman | Feb 15, 2023 07:25pm | #4

   I did add-on overhangs with 2x4 rough sawn tails scabbed onto the trusses. It was very easy to piece OSB sheathing and exterior insulation around the tails. It was also easy to create a baffle for the attic ventilation.