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edwin plowman
6/2/2007
I'm wondering about roof design and efficiency. Concerned with cooling costs, not heatiing.with correct insulating, installation, ventilation, etc. could you comment on the following? What about the volume of attic space? is there a pitch range is conducive to reduced heat gain? (thinking angle of the sun hitting it) Gables vs hip design--which results in less heat gain? how does the guage of metal come into play? and finally...What about orientation in relation to the sun? (direct light on roof, gable, or corner etc)
Todd Miller
Isaiah Industries, Inc.
6/6/2007
Steeper pitches will be somewhat better but the increased overall roofspace negates a part of that. I would focus more on a good roof system than pitch. Large volume attics require more ventilation but are also easier to ventilate usually. Gable roofs are much easier to vent than hip roofs. Metal thickness has little bearing. Try to have direct light on the gable end. Consider a light color roof or a dark roof with reflective pigment. Consider as much ventilation as possible.
Guest User
6/8/2007
Thank You Todd! If you could elaborate a bit please. Which is more effective, a light color or the reflective pigments? Whatr about just galvanized metal? How does "plain" compare to "painted" metal as far as longevity? For venting are fans that effective? I'm thinking solar assisted/powered fans using thermostats. In conjuction with the rest of a good system :)
Todd Miller
Isaiah Industries, Inc.
6/10/2007
A naturally light color roof will have somewhat greater reflectivity than a dark roof with reflective pigment. Natural metal will lose reflectivity as it ages. It also has lower emissivity than painted product. Ultimately painted product should have greater durability than unpainted, all things considered. My thought on ventilation is that you want to continuously bathe the underside of the roof deck with fresh air. This is done well with soffit vents as intake and ridge vent or lots of box vents as exhaust. When you add a power fan, you start to disrupt this natural convection and air flow starts to run in patterns which I feel is the lesser option.
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