too many vents, who knows?

Old 11-20-05, 09:35 PM
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too many vents, who knows?

I 've been roofing for about 7 years here in Middle Tennessee. As a licensed contractor, in this time I've done about 600 houses and my call back rate for these 600 or so has been about a total of 5 houses and this was usually attributed to some type of storm damage. So, I feel like a know what I'm doing, but this one has got me stumped. Case in point: small (950) square ft farm house, older (built in '42). If been called back 3 times for leaks. Here's the catch: When I first bid the job 2 years ago, the homeowner refused to part with the 6 square roof vents, 3 whirleybirds, 2 powervents, an additional 3 other hodge-podge assorment of roof vents, and a partridge in a peartree. He wanted a 2nd roof of O/C three tabs laid and insisted on keeping the all the vents on the rooftop. This farmhouse looks like a Japanese Steakhouse with all of these protrusions but I'm the MAN, so I roofed it for him. He revealed something to me which I thought was interesting at the time but I filed it away as most of us do. He said that for many years, frost would form on the underside of his tongue and groove poplar roof decking. I kind of joked that maybe his house was built upon an Indian burial site. Well nowadays, he's telling me something new, "my roof is still leaking in the same spots it was before you installed the new roof". He's 86 years old and annoying as heck, he even sat on the roof the whole time I laid it and practically watched every nail being driven. Oh yeah, and o'course, grandpa wanted those shingles double-nailed even if it split his planks. I believe that he has too many vents and that possibly moisture is being sucked into the attic space,(i.e. the frost he's seen before) and maybe even the whirlys aren't getting enough draw to spin themselves and sling away rain. He's got a medley of small square 'stove vents' on a section about 12 ft below the whirleys, Could they be short circuiting the flow of air to whirleys. The whirlys are about 15 years old, but they spun true and didn't squeel, so I didn't fight him on replacement of them. But I also noticed that they are old enough that they don't have the small creased ridges on the edges of the hood louvers like the new ones of today. I don't know about you guys, but I consider these folks neighbors and even after 2+years beyond my installation warranty I still need to help them out with this or at least educate them about correct ventilation requirements. I have never ditched a homeowner on little things like this and I even place this as a priority over new additional work and that has gotten me SO MUCH word of mouth business. By the way, I only do work for homeowners and most of that is tear-off business. The only people who've ever screwed me were general contractors, they're always over-extended on all of their pay-outs and usually "in Florida" or "at the Lake" when you've sweated your guts out on some 60 square 12 pitch cut-up condo and it's time to collect your money. With my homeowners, I don't pester them for anything down, nothing is collected until all work is completed, and my guys are not whining about donating plasma on my jobsites. Anyway that's just me. If any of ya'll can enlighten me on this ventilator situation, I would most kindly appreciate it. Thanks...Rick
Old 11-21-05, 06:23 AM
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I ran into a home owner last fall that said he's having the same issue as your customer. His house is a 18 sq 1920's fortress. 26 inch thick walls! I tore off 2 layers of wood shakes under a layer of three tab shingles re-decked and put down Landmark 30's, ice and water to code, valley flashing to code, and cut in vents to code. He had some leaking last winter and noticed lots of frost and ice up under the old roof boards. I've never seen a house built like this one. After everything was tore off it had the old boards run with a 4 inch gap with what looked like cement or plaster with small boards like old houses have on there interior walls however this was down a ways under the roof boards. The house also seemed to have a ton of insulation (10/12). After my helpers left one day while tearing off prior to decking a pretty nice storm came up and rained pretty heavy for several minutes. I tried to tarp the roof but I know it didn't cover everything. The homeowner had the house locked up tight as he was on a fishing trip and wouldn't be back until I was done roofing the house. When I got back I told him what had happened with the rain and he said he didn't see one drop of water in the house! I was happy there was no damage got paid and went about my merry way.

Now consider this, is his house too air tight and not won't let moisture out? Every peak had air vents installed every 6 feet. I've not been back to the job since I finished it as the homeowner knows the issue is not my fault.

BTW, the year I roofed the house was the year he bought the house.
Old 11-22-05, 05:02 PM
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If the roof leaks in a good summer rain you trouble shoot the roof.
If it is frost or condensation in cold weather covering the underside of his roofboard and is widespread he has too much moisture in his living quarters.
Usually caused by running a humidifier too high, old people do that a lot.
Also if he has a high water table and a crawl space under his house, heat ducts which run under his house, this heats the ground water under his and creates a super humidifier. The moisture rises, condenses on his roofboard in his attic. I have seen it many times. Had inspectors in attics verifing this.
If this is the case theres not much you could do as I have seen condensation on vents. He must get at the root of the problem and reduce the sauna.

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