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I am doing an extensive roof rework this summer. New interior vapor barrier, cels, rigid iso board, sheathing, then metal roof. Everyone I have spoken to has said that regardless of the retrofit I must vent the sheathing. With the metal roof being absolutely impervious, the venting (even a 1/2″ airspace) is a must.
So, I don’t like the looks of soffit vents, and I am planning on installing soffit lights. My brother (who dabbles in architecture) suggests using open trim rings on the lights and covering them on the inside with screen. I don’t think there would be enough airflow through the fixture itself, so bro suggests adding blank trim rings between the lights. All looks kosher from the ground, and the trim rings could be popped off to check the progress of the roof rot. Anyone else done this?
One downside – when the lights are turned on it would induce a draft and hot air into the airspace. No problem in the summer, but maybe ice causing in the winter.
I was surprised when local lighting supplier told me no one buys the air-tight recessed fixtures. Probably because they are $24 instead of $9. I wonder, are these “air tight” fixtures actually air tight? Would Gene and Freddy approve of their use in the top floor ceiling?
-Rob
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Hi Rob,
Just my opinion, but I think the heat of soffit lights in the winter would be a bad thing.
I have seen Fred defend the airtight lights in print in the past. Still, methinks no holes at all in the top floor sceiling would be best yet.
Steve
*RobOne of the biggest $$ benefits of a new metal roof is saving the materials & labour of sheathing the roof by using strapping/furring/perlins (whatever your local parlance) instead. Just strap over the iso.at 24" oc. and leti thatair gap provide whatever venting the metal itself needs. The iso ( foil faced or not, apparently) won't allow any moisture from below through any way, so if you've got moisture at that point,either you've got a void in your air barrier, or a design problem. By that point, only the magic diffusion charteristics of cells will save you!! i "So, I don't like the looks of soffit vents, and I am planning on installing soffit lights."That'll fix the sob's. . . F**k em if they can't take a joke!! LFD!!
*PatrickI agree with you completely on the moisture barrier thing. But the roofing people say that small amounts over the life of the roof will accumulate yada yada yada. The roofing I have selected is Metal Sales pan & batten. It needs to be applied over sheathing (26 ga). They make a 24 ga but it costs 70% more. ($2500 plus in materials for 9 square), so I am "settling" for spending only about $1500 on the 26 ga. I think they say over sheathing because this has a 12" wide flat pan between the ribs. If this were corrugated I think I'd be okay with the furring strips.-Rob