Ridge Vents – see light?
I was at our new construction home yesterday. It is not yet insulated. I looked up and noticed one small hole where light was coming through. It was at the peak of the roof (runs along the length of the house – it is a ranch). The was no plywood in this area – just synthetic tar paper/shingles could be seen. Our builder said this just where the shingles come together and that no water or anything can get in there. If they put plywood under it, it will wick and rot. He said he could put steel wool there or caulk it but that is not normally what is done. It is normally just left open to vent. I just saw the one spot where I could see light, but he says that there are many other areas where you can see light coming through. Is this normal protocol? We are building an air tight house and this definitely doesn’t seem airtight….Thank you!
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If the roof is going to have soffit to ridge venting this isn't a big deal. If it's going to be insulated at the roof deck in an unvented configuration is is. It's an air leak, but there is no such thing as an air tight ridge vent- a vent can NOT be air tight and still function. It's either vented or it's not. Rigid vents typically use polypropylene roll mesh under the cap shingles as critter-control.
I'm not sure what the guy is talking about with the "...this just where the shingles come together and that no water or anything can get in there. If they put plywood under it, it will wick and rot." business. Can you post some pictures?
I can try to get a picture when I go out there. It is up very high, so it will probably be tough to take photos of. I just saw a "hole of light" about the size of a quarter. I don't think and roll mesh was used, but I do know something like this was used for ridge vents:
http://www.airvent.com/index.php/products/exhaust-vents/ridge-vents/shinglevent2
What they refer to as the "weather filter" in that hard-shell ridge vent is probably equivalent to the polypropylene ridge vent material.
http://www.airvent.com/images/products/product-pages/shinglevent2/sv2-diagram.jpg
http://www.roofsaver.com/images/Howitworks.jpg
Carolyn,
If your builder installed a ridge vent, that means that you have a vented unconditioned attic. If you can see light at the ridge, that's a good thing. If there were no light at your ridge, that would be cause for worry.
I wouldn't normally expect to be able to see a "hole of light" in a properly installed ridge vent. The Air Vent / Cor-a-Vent type products should be butted tightly end to end, so there are no gaps. In a dark attic you can see a glow of light coming through them during the daytime, but any openings will let insects or even bats in. I would probably want to make sure that any holes are tiny, and if they're not, ask the builder to make sure there is fine wire mesh installed to fill them.
Before I install any vents I cover the opening with 1/4' galvanized mesh. Rodents can make short work of most vent screens.