Old/Smart roofers please help me

Sorry no pics on this one. I got a redeck job that is wood shakes with a layer of asphalt shingles over. It 12/12 and pretty standard stuff except it has a rounded dormer above one window. It looks like a cone that has been split in half sideways.

Honestly, I have never decked over something like this. I question if I can make 7/16 OSB(waferboard) conform to this curve. Any suggestions? It’s a pretty tight radius of around 4 feet at the bottom and tapering to zero at the top. It is sort of shaped like a teardrop.

I was thinking of maybe using 1/4 inch plywood and just doubling it up? I really don’t know what kind of structural support is under there until I start tearing it off. I suspect it has a tin bottom. Those old timers could do things with wood shakes that are a little harder with asphalt shingles.

Also, second question is about putting drip edge on this curve. I have seen people put a series of cuts every 2-3 inches to curve drip edge but this always looks tacky to me. Should I just put Ice and Water shield down and wrap a one inch piece of copper/galvanized around the radius? I am leaning towards just leaving any edge off the elevated part of the curve. Let me know…

Instead of trying to wrap a sheet around it. Cut the sheet into 1’ or 1.5’ wide strips and install them from the valley out to the rake edge, sort of like installing shingles. You bend a sheet of wood around that thing it will probably rebound back, unless you screw the heck out of it.

We usually use 2 layers of 1/4" plywood to deck curved stuff.


Go with the 1/4 inch, 3 ply cdx. ( I don’t mean three piece’s) for the witches peak, & try lead on the curve the thinner the better. Be careful its delicate. Wear gloves.
WoodPecker Roofing
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I wouldnt try and re shake that thing either. After you re deck it, ice and watershield it, then go with horizontal sliplock red copper panels. Thats how I do my cones, eyebrows, & half rounds.

this is what we do on all of ours. you just make cuts and nail it down. We have used 1/4" before too, but either way works well. No reason to make it more difficult than it is.

or you could always have put a standing seam copper panel on it.