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Applied rafters on 7.5/12 Roof

brooksbend | Posted in General Questions on

Hi, I have yet to find a detail for adding applied rafters to my situation, so I drew something up to post here for feedback. The closest I found was John Abrams detail, attached here, but there’s no exterior foam on the detail and 1. seems like a steeper pitched roof and 2. seems like less of an overhang.

I’ve got a 7.5/12 pitch roof, finished with Standing Seam, Climate 5 (Western Massachusetts). Using 2 layers of 2.5″ foil-faced polyiso, tescon taped on the second layer. The feedback I’m looking for here is whether the applied 2″x4″ rafter will be strong enough here. The 1″ boards coming from the peak to the eave is my strapping for the foam, 8″ timberloks every 24″. The 1.25″x4″ perpendiculars are for the standing seam, two clips per board, every 24″. There would be one where I show it at the drawing, one at the end of the frame, and 1″ boards in between that would be showing from below on top of the applied rafters.

Overhang is 14″, length of 2″x4″ rafter is 16″.

I would probably only put 1 timberlok per 2″x4″ rafter, the one further down in the drawing. All lumber is grade #2 or better rough-cut, full sawn.

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  1. maine_tyler | | #1

    Not an answer, but I suggest searching Google with the following:

    applied overhangs

    There are lots of discussions on this topic. The "site:" limits results to GBA which gives a good return on this subject

  2. Expert Member
    Michael Maines | | #2

    I would trust (and have used) that detail, on two conditions: the applied tails are 2x6 as shown in the drawing and not 2x4 as written in the question, and that the roof sheathing continue over the tails. You'll want double sheathing anyway so the roofing nails don't show, and by having the top layer continuous with what's on the roof, it helps in keeping it from sagging.

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