Ridge and soffit question

[mksanny]

I am having the shingles on my roof replaced. My roof has a ridge and soffit attic ventilation system.

When I look up in the attic, I see there is a gap between the wooden boards that make up the two sides of the roof. I assume the gap is there for the air to flow thru. However the gap seems to be covered with some black semi porous material right above the wood and does not seem to allow a whole lot of air thru.

My question is.. when i look up thru the gap in the boards, should I see some daylight that would tell me that there is a way for air to pass freely? I can't see any daylight now and suspect air can't move around that easily.

[trader4]

There are a variety of materials available for ridge vent solutions. Some of them are porous dark material, almost like what you would see in a room air conditioner filter. So, it's not unusual to not be able to see daylight. When they do the shingles, they should put in a new one anyway. So, you can do some research and find what kind u want.

[Dottie]

I recently had my roof replaced and was wondering the same thing ... after all, it needs a place for the hot air to escape. Anyway, the men who did my roof came back yesterday to work on a house down the street and I asked about my ridge vent. I found out it's called a Cobra Ridge Vent ... (I had seen the box. But when I looked up from beneath - into the attic - I could only see the cut away at the top and solid black, like the bottom of a shingle on it. ) They showed me a piece of foamy black stuff - one of the men blew into it and I could feel his breath come out the other side. It was not rigid the way I had expected. So it's possible you have the same thing. This stuff would look black from the bottom.

[Paul Franklin]

Well now think about it...if you could see daylight, what would happen when it rains? :-) I know, you meant you would think you should be able to see light...and I'll bet if you turned off all the lights, you would see a little glow.

There are several styles of ridge vents, but probably the most common is shingle over style. It's a flat woven plastic mat that gets laid down over the gaps you mentioned. Then shingles are applied over the top so it blends in fairly well with the roof. The air rises through the slots in the sheathing, and then has to flow sideways through the plastic mat until it exits from the thin edge of the material.

The material is made to allow a reasonable amount of air to flow, while preventing insects from getting in.

It doesn't seem like much air will flow, but because it runs the whole length (almost anyway, there is usual a foot or so at each end that isn't vented) of the roof, it adds up to sufficient area to allow enough ventilation.

In short, what you are describing sounds typical.

HTH,

Paul

[Al Bundy]

[e-mail] wrote in news:1187361953.904524.286200 @i38g2000prf.googlegroups.com:

The attic air dows not go out and straight up. It goes out the sides of the vent. The top if the ridge vent is covered to keep weather out. You go up there on a hot day near the ridge vent. As hot as the roof is you'll feel hoter air near the ridge vent.

Here's an animated airflow of how it works. Probably take forever on dial-up.

[Dottie]

I posted this question on another discussion - one about my roof. I have just discovered that the roofers used the method you describe on my own roof. The contract called for a Cobra ridge vent. Before I start asking them to come back and fix it - I need to know (1) is the method you describe as effective at moving hot air out as the Cobra ridge vent? Is there anything about it that would void my warranty of the shingles? I really don't want to have to go through the ordeal of having them come back and do it over. We have had some really bad rains lately - and the roof does not leak. My main concern is the constantly running a/c and I wonder if the attic would be cooler with a ridge vent. Your opinion would be appreciated.

[Dottie]

Now I can answer part of my own question. The roofing contract calls for a "Cobra ridge vent" and that is what I got. I just didn't get a rigid vent. I hope that what I have works all right because I will have to stay with it. My neighbor also has that written into her contract but she did discuss it with him before he started working. She has had problems with rats in the attic and told him she wanted a "metal" vent or something to keep out rats. So, he may have installed one in her attic or if not, he may come back and correct it. We checked him out as thoroughly as possible before hiring him and he got only good references. So, maybe it will be o.k. Now I better go do some research on new air conditioners....got a feeling that's next.

[trader4]

quoted text -

The ridge vent is only part of the attic ventilation system. Do you have adequate soffit vents so cool air can get in? Are you sure they are not blocked by insulation, which is quite common? All too frequently the insulation in the attic is installed with it shoved up against, and blocking soffit vents. They have plastic shute type baffles that should be stapled to the underside of the rood deck, between rafters, for a few feet, starting at the low end of the roof, by the soffit vents.