Roll Vent / Ventilation Question

About 2 years ago my brother and I put another layer of shingles on my mother in laws house, when we did it we replaced the aluminum ridge vent with a RollVent shingle over ridge vent. And She’s been complaining that the house is much hotter in the summer than before we re-did the roof and we also went with a lighter shade of shingle, so I went and checked the attic and I found a lot of black mold/mildew growing on the plywood and even patches of dark stuff in areas of the insulation. So it appears the new ridge vent isn’t providing adequate airflow.

How should I fix this? Rip it up and replace the ridge vent with another aluminum one or something else? ShingleVent II is another shingle over style that claims to have better airflow, but I dont’ know after my first experience with shingle over venting… She wants me to add one of those solar attic fans, but I’m not sure thats the best solution either…HELP, I need ideas.

2 Questions everyone is going to ask :

  1. Did you had proper intake ventilation ??

  2. Did you block the gable vents ( if any )??


They did not change anything and it worked before.

What other changes where made to the house? New windows, furnace, AC…

To add with what left said, many people upgrade the windows and never upgrade the insulation in the home. So many window companies could make a fourtune from insulation. WHen you up the R value on your home with windows that warm air will have to go somewhere and it will go up. If you live in a cold climate your R value should be somewhere in the 42 range and many people have basic R19. Lack of soffit vents could cause this also.

There were no other changes…just added a layer of shingles in a lighter color, and changed the ridge vent from an aluminum one to the Roll Vent shingle over style. And I did that largely due to my bee alergy, the original one that was up there let a lot of bees in. There were many wasp nests along it. And the roll vent style from the look of it wasn’t and didn’t let ANY in…nor enough air through either.

The house isn’t that old…it was built in 1988, and the original shingles just failed early. I heard there were a lot of bad shingles produced around that time, but since they were on the house when she bought it, we didn’t have receipts or anything for a warranty claim on them. Also, there are no gable vents.


Just a quick thought…

When I lived in Va. We used Cobra roll vent . The wind used to kick up the dust quite a bit. Over a period of time the mesh would get clogged with debris. It would take approx. 2 to 3 years to build up. If the type of vent you used then I would look into that aspect.


I don’t remember who made it…it looked like this stuff though.

This is the type of shingle over ridge vent we use in Alaska. It has a baffle system that does not allow blowing snow in and does not clog. It also is made of hard plastic that will not “squish” down when you nail the capping on. … mier12.cfm


Ok before we start guessing lets start with the basics. Give us the length and width of the home in feet. Then tell us how many feet of ridge vent you are using. Then tell us how many soffit vents you currently have.

When we get that information we can let you know if the ammount of ridge vent you have is not enough or there is a lack of soffit vents. If these are ok then we move to step two. Just post the outside dimensions so we can let you know if you have enough. Adding a power vent will increase the problems. If it is raining in that attic you will have to replace all the insulation. If it is wet it is not any good anymore.

Now if the ridge vent you use is not hard plastic then it is junk. It will clog up and not work.

Please send dimensions so we can figure this out.

Nothing is wet or damp to the touch, and there aren’t any leaks.

There is no hard plastic shell or framework to the vent. It’s a material simlar to a scrub pad…maybe a little firmer and not as dense. But it’s not like some shingle overs I’ve seen that have an actual plastic bafffled framework that gets nailed down first and is then shingled. This thing is rolled out over the vent and nailed down at the same time as you shingle it. I wish I had some good pictures.

Well without the information i asked you for it will be hard to tell if you have enough ventilation. With that i have no clue what the problem is. I need the information to make an educated opinon. Odds are that the vent is clogged. It must have gotten wet somehow to form mold. It is condensation not a roof leak. If you give me that info i will tell you if you have enough intake and exhaust because i see that problem every day.

Ok…House is about 60’ x 25’, the soffits are done by perferations built into the vinyl siding material that runs under the eaves and runs the complete length of the house. The ridge vent runs about 45-50’ of the 60’ length of the roof. It only skips about 4-5’ on either side of the chimmney at one end, and stops 5’ or so from the other end of the house.

This is just a wild guess … but could it be possible that during the installation a heater pipe or bathroom vent got disconnected in the attic and all the moisture runs in ???

just a guess i see it all the time :expressionless:

Ok With those dimensions i think i know what your problem is. For the soffit vents to meet code you would need 40 sections of the perferated soffit material. The ridge vent has very little intake. Therefore it can not exhaust the warm moist air. Now i doubt you have the 40 required by code and to maintain shingle warranty. The old aluminum vents worked differently and are not as effiecent as the vents now a days. My suggestion is this. Remove the ridge vent totally since im sure you will not install the correct ammount of soffit vents, and put in a PowerCool Plusâ„¢ 12 – Premium Roof-Mount from Air vent. It will cover the amount of attic space and keep the humidity down. Im not a big fan of solar powered jobs i trust live wire hookups. You can use a solar one if you would like but for that size attic you would need 2 of them on opposing sides of the roof.

Here is the website to look at what im talking about: … Roof.shtml

Also if you have a fan in the bathroom make sure and exhaust it to the outside of the roof. That can cause moisture also. You have a moisture problem there and you have to get the humidity out and this vent has a humidistat to help with that. Hope i could help any other questions feel free to fire away.

also go in the attic and check to see if the insulation is blocking the airflow at the soffitts. look for insulation baffles.

Odds are im betting he does not have enough soffit to begin with.

I don’t think the soffits are the problem…they do have insulation baffles in the attic…and they run the entire length of the house on both sides, so I don’t see the problem there. Here’s a pic, since maybe I am not explaining it well. They’re done by perforations built into the vinyl panels under there.

so its open all the way accross ?


Where exactly is the ice damning? Is it high or low. Are there any breaks in the baffles all the way to the ridge vent? Is the knee wall blocking intake and exhaust?