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TOPIC: Ventilation

Flashing around power vents

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I am getting my house re-roofed over the normal dimensional asfalt shingles with the Vail Titan Steel Shingles. I noticed there are several techniques to flash around pipes, chimneys etc when you have a lot of vertical portion of the thing you are flashing around to do the actual flashing. BUT what happens when the installer comes to those power vents where they are very low profile and the screen intake for them is basically at deck level. How can flash that??? I think I heard they can't flash anything that low and have to rely more on caulk only and whould always be a leak prone area. I understand that this is not a issue for the normal asphalt roof since the flashing of the power fan becomes a shingle and allows the water to sheet naturally but you could not to do this on a metal roof since the fan flashing would definielty not sit flat and would also probaly contriubute stains etc to the metal directyl underneath. Is there some other power fan you must get that has extra vertical relief? There is not much you can ridge vent on my house and need the extra power fans for proper ventillation to meet code.
chris nigel
chrisnigel

8/23/2005
First Custom-Bilt Metals is a MRA member manufacturer and you should direct the question to them. I will say first that a power vent is not the primary choice of ventilation and if you are re-roofing it is the best time to correct the situation. The code calls for a 50-50 balance of air at the eaves and ridge. The volume needs to be in excess of 1-150sf of ceiling area. This is a good investment and will return energy savings and extend the structures life. As to the power vent installation, it is generally the same with metal shingles as asphalt shingles. If you reuse it it will need to be lifted and re-installed with the new shingles in the same manner.
Allan Reid
Dura-Loc Roofing Systems, Inc.

8/24/2005
I don't have enough of ridge to ventillate. I have to have the power vents for that reason. One more question about ridge vents. The little of ridge I have I would like to have of course ridge vents. But Custom Bilt Metals and really everbody else seems to use caps for the ridge the same ones as lets say for the hips. Is this supposed to be like a ridge vent? It seems they should have a more rasied piece for maximum ventilllation. Do metal shingles even have ridge vents as part of the normal kit accesoories. It seems to me that they do not and the asphalt ridge vents have a real openeing for maximum ventitalltion
Guest User

8/24/2005
Chris, The standard cap accessories with metal shingles are not vented. However, I believe that every manufacturer will either offer a ridge vent or have details on how to create one or how to adapt a commercially available ridge vent. If you work with the manufacturer, you may find that their are options for venting the hips as well. Custom-Bilt is a member of the MRA. If you contact their corporate office, I am certain they will help you. Todd Miller
Todd Miller
Isaiah Industries, Inc.

8/27/2005