We are getting estimates for a new roof thanks to a hail loss claim. We are looking at GAF Timberline HD. Our current roof uses box vents on the back of the house that seem to have worked fine over the last 15 years. Other options are the ridge vent of course and one roofer is recommending 3 colored wind powered turbines to replace some of the current box vents. I've never been a fan of ridge vents, a neighbor had one of theirs blow off, they look prone to leaking and one roofer would recommend box vents over roof. I'm not a fan of the wind powered turbines, all the ones I've seen end up looking like junk prematurely?

Thoughts? Box vents, ridge vents, or turbine vents?

Skip the roof vents. Put gable vents in on the end walls (gable walls) and temp controlled attic fans. One end evacuates the hot air, the other end pushes in fresh air. works incredibly well. It’s what we had when we lived in Washington. It rains too much for box or ridge vents there.

Double hipped roof, no gables. Only soffit vents for intake and something on the roof to vent.

We've a hip roof on our ranch. (Dunno what "double hipped" means.) Had a tear-off, sheathing replacement and re-shingling done by an Owens Corning Platinum Preferred Contractor a couple years ago. They put in ridge and hip vents. They, and O-C, must believe in them, because the roof has a 50-year unconditional warranty, incl. labor, backed by O-C. One-time transferable.

Google the words "should I have a powered attic vent". In a lot of cases they are completely unneeded. Your roofer if he's worth a damn should be able to tell you.

Unless you are living in a 10,000 sq ft home there is no reason to have three powered vents. The only reason to have one in most cases is comfort. You can cut temperature disparity from first and second floors by a degree or two, maybe more, but it will cost you a good amount in electricity (look up negative pressure attic).

Convection is your friend. If you have free soffit vents, then a ridge vent in most cases is best bet. Old fashion roof vents are GTG too as long as combined with sufficient airflow in (soffit vents). Powered vents really, really rely on clear soffits.

Going to bed now will type more if you have questions after doing some googling. Efficeicy is never a reason to have a powered attic fan, you can not win that game. Electricity cost, plus fan, plus other HVAC/electricity costs.

I have had roof vents in the last two homes I have owned and have absolutely no problems. That would be a total of 30 year span. On this home we also went with gable vents as it gets so damn hot here in the summer. No problems after 15 years.

My last house (in NC) had gable vents and soffit vents...neighbor had both and added ridge vents, his attic was much cooler than mine. I added a temp controlled fan from Lowe’s to one gable end and it reduced the heat remarkably. I figured all the heat under the sheathing and shingles would reduce the lifespan of the shingles.


Here in TX we have a few box vent with soffit vents for intake. They seem to work but it’s hot as F&$k up ther in the daytime., I see some neighbors have the turbine vents, I don’t see ridge vents anywhere in new construction here.

The roofing construction here is plywood with a foil covering on the inside, some kinda plastic layer then the shingles, no felt, I guess it’s the heat that kills it or something. They say the foil keeps the heat from destroying the plywood. I might add a fan to the attic if I can, just to help move the heat out quicker.

quote:

Originally posted by Scuba Steve Sig:
Double hipped roof, no gables. Only soffit vents for intake and something on the roof to vent.

How big is your house and how many linear feet of ridge do you have?
There is a formula to verify if you have adequate ridge for venting and I’ll have to look it up before I can give you a definite answer...

My crews put on 2-4 (Owens Corning) roofs a week and we use OC VentSure shingle over ridge vent on 90% of our roofs, nary a problem. They are baffled to prevent water entry, and they do. GAF has their own offering also, I'm sure. They will probably want you to use it, along with a certain minimum number of other GAF branded products (hip/ridge shingles, synthetic underlayment, ice and water shield etc) to get an extended warranty. Read the fine print, OC requires the use of their intake soffit vent in conjunction with the ridge vent to be counted as one of the qualifying items towards the "Total Roofing System" warranty. Speaking of intake, make sure you have a sufficient amount of intake at your soffits (plus proper vents) and gables, if any, to provide airflow for the ridge/boxes to exhaust. Without it, you're subject to ice dams (which can lead to water intrusion) and other problems.

Occasionally we still use boxes when there's not enough ridge length to cut in ridge vent (hip roofs), and they work fine, always have - people just want the cleaner look of ridge vent. My guess is that your neighbor's ridge vent blew off due to a lazy ass using the short shingle coil nails to apply it instead of longer hand-pounds.

quote:

Originally posted by Bassamatic:
I have had roof vents in the last two homes I have owned and have absolutely no problems. That would be a total of 30 year span. On this home we also went with gable vents as it gets so damn hot here in the summer. No problems after 15 years.

Same. It's what is on my roofer's home. I've known him for 15 years personally, and he's done two roofs for me. Ridge vents with soffits. I can go in my attic and feel the air moving in the dead of the 100 degree summers. Ridge venting needs soffits, and lots of them. No solar or turbines necessary. Have never had a leak either.

I replaced the south facing roof shingles a few years ago cause I was tired of getting up on a 7-12 inch pitch roof and replacing shingles blown off in storms. One contractor wanted to put a bunch of vents in. He was pushing them and is part of the reason I went with someone else. No one is going to cut holes in my roof! No frikin way!

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Originally posted by smlsig:

quote:

Originally posted by Scuba Steve Sig:
Double hipped roof, no gables. Only soffit vents for intake and something on the roof to vent.

How big is your house and how many linear feet of ridge do you have?
There is a formula to verify if you have adequate ridge for venting and I’ll have to look it up before I can give you a definite answer...

I guess hipped roof is the proper term. Its about 1300 sq ft footprint, with a high slope, but its all "neo-eclectic" with a couple different rooflines in there to lose efficiency in the design. Some north-south rooflines, but mostly east-west and that east-west prevailing ridge is about 35-40 linear feet. I think there are currently some 13 box vents. Being in Iowa, summer heat isn't too much of a problem, its getting rid of winter heat under the roof. Our current layout seems fine, we have a generally east-west laid out house with prevailing winds from the west, so I question the benefit of a ridge vent, but it seems that is what is usually down with reroofs around here. The interwebs say you get alot more out-vent capacity than box vents that way. The roofer wasn't recommending powered vents, but wind turbines. I meet with the 2nd roofer tomorrow.

I'm guessing either way, a bigger improvement will be the bathroom vents venting outside the roof instead of somewhere within the attic. Since that hasn't caused a problem with the roof decking in 15 years, I'm thinking the current ventilation method is more than adequate.

Went from powered exhaust to ridge vent when I had mine replaced, world of improvement. One less thing to fail (motor had died a few months before). No problems here with leaks at all.

We have GAF Timberline and if you want their warranty, use their system and their system only. GAF has their own venting systems. We have their Cobra ridge vents and it works just fine and we have had very high winds since the install 2 years ago. If you need any additional roof penetrations for bathroom exhaust vents, etc. do it when you have the roof done.

Also, GAF has a list of their certified installers. Use a top rated one and one who has been in business for years. Trust me on this!

quote:

Originally posted by jcsabolt2:
We have GAF Timberline and if you want their warranty, use their system and their system only. GAF has their own venting systems. We have their Cobra ridge vents and it works just fine and we have had very high winds since the install 2 years ago. If you need any additional roof penetrations for bathroom exhaust vents, etc. do it when you have the roof done.

Also, GAF has a list of their certified installers. Use a top rated one and one who has been in business for years. Trust me on this!

From what I read and was told by the GAF certified installer, box vents qualify for their warranty.

Wind turbines blow off during hurricanes. If you are going to use them get high quality aluminum wind turbines with self lubricating ball bearings. They last much longer and do not squeal and stop turning. Probably not too many hurricanes in Missouri, but high winds do cause some problems. Another issue is the direction of the prevailing winds.

The more roofing vents you have, generally the better it is. Shingles will last longer, your air conditioning will have less to contend with (most homes ductwork is in the attic, and roof heat) etc.), and less mold issues. Generally it is a win win.

Ridge vents are very efficient. I’ve used on last 3 homes. Since I was involved in design of second house, I used vent skin design. Ridge vent and instead of soffit vent, installed brick vents just above the foundation.

This allowed air to be drawn in near ground level and create a rising curtin of air in space between outer brick veneer and inside wall that vented into the attic to be released out through ridge vents. Air rising through this wall space carried heat radiated from brick veneer into the attic and out.

Combined with Cool Ply roof decking, electric bill was less than previous house which was half the size.

Worked well in town south of Houston with high summer heat and humidity.

quote:

Originally posted by Scuba Steve Sig:

quote:

Originally posted by smlsig:

quote:

Originally posted by Scuba Steve Sig:
Double hipped roof, no gables. Only soffit vents for intake and something on the roof to vent.

How big is your house and how many linear feet of ridge do you have?
There is a formula to verify if you have adequate ridge for venting and I’ll have to look it up before I can give you a definite answer...

I guess hipped roof is the proper term. Its about 1300 sq ft footprint, with a high slope, but its all "neo-eclectic" with a couple different rooflines in there to lose efficiency in the design. Some north-south rooflines, but mostly east-west and that east-west prevailing ridge is about 35-40 linear feet. I think there are currently some 13 box vents. Being in Iowa, summer heat isn't too much of a problem, its getting rid of winter heat under the roof. Our current layout seems fine, we have a generally east-west laid out house with prevailing winds from the west, so I question the benefit of a ridge vent, but it seems that is what is usually down with reroofs around here. The interwebs say you get alot more out-vent capacity than box vents that way. The roofer wasn't recommending powered vents, but wind turbines. I meet with the 2nd roofer tomorrow.

I'm guessing either way, a bigger improvement will be the bathroom vents venting outside the roof instead of somewhere within the attic. Since that hasn't caused a problem with the roof decking in 15 years, I'm thinking the current ventilation method is more than adequate.

According to my calculations you need a minimum of 624 Sq. In. of both soffit and ridge ventilation. This equates to about 17 linear feet of ridge vent so you should be fine.
However, venting of your bathroom (or any venting into your attic) is against code and should be remedied.