Putting on a new Roof

I am in the process of stripping old shingles, putting plywood over old sheathing and adding new shingles. The roof is over an attic that was converted into a bedroom. The current roof has a ridge vent but no Soffet vents. I was told that the best way to add a soffet vent is to put strapping down between the plywood and old sheathing in order to create a ventilation space. Then cut holes in the top of the old sheating over the eaves. Then put he plywood down, cap the space and add the vents on the bottom side of the eaves. Is this the correct way to do this???
Thanks in advance!
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wrote:

It's *A* correct way to do it, although I suspect that using something thicker than strapping would get you better airflow. (The strapping is running eave-to-ridge, right? not gable-to-gable?)
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Yes that is correct the strapping would run eave-to-ridge.... Are there any products out there that I could slide in under the current sheathing to create channels? It would be nice to just have to go over the old sheathing with plywood and not have all of the problems associated with spacing the plywood up. I was wondering if I could remove some of the old sheahing and slide some kind of duct in between the sheathing and the insulation???
Goedjn wrote:

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You need something more substantial than strapping. Especially if you want to insulate.
In a house where they had a T&G cathedral ceiling, they ended up going with 2x8's on edge. 5.5" fiberglass batts on top of the T&G, then 2" worth of air gap before the plywood sheathing.
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wrote:

Not that I can think of, no. And it would compress the existing insulation probably more than you want, anyway.
Look at it this way, This is an excellent opportunity to add a 1" layer of urethane foam on TOP of the existing deck. (Foam, then sleepers, then nailable deck.)
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snipped-for-privacy@h2kustom.com wrote:

I had the *exact* same thing done here at home, they're finishing off the job inside as we speak.
They tore off the planks 3 ft from the bottom and 3 ft from the top, put strapping horizontally, then 2 by 4s onto the existing chevrons effectively raising the roof about 4 inches. Then aspenite, membrane, shingles, and a couple of static ventilators on top, model 301 as shown here: http://www.ventilation-maximum.com /. That's the ventilation part.
We're having urethane blown on the inside, about 5.5 inches, so basically the same principle applies: nailing 2 by 4s to the existing structure to give more space, urethane everywhere, gypsum, primer, paint. For the exposed urethane in the storage areas we had this fireproof coating applied. Yuk.
Oh surprise there was never any ventilation from the soffits in front, the existing plywood(!) that blocked them was removed so now we're okay from the soffit right up to the ventilator.
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Sorry I meant to say exact same problem.
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