Are they worth it?

I am having to cut a gable vent on my house cause the box vents are not providing nearly enough ventilation. My attic has been nearly 145 degrees the last couple days and realized the gable vent is only for show. They fit the outside aesthetic piece and finished around it but didn't actually cut the OSB or install a louvered gable vent.

Any help or guidance is appreciated.

Do you have ridge vent? Power vents? Solar vents? Airhawks ? Soffit vents? What's your setup? Gable vents can be pretty inefficient if it's not set up right.

I have soffit vents about every 8 ft on the eaves, front and back of home along the red line. Seem pretty standard vent size 6x12-ish. There are 7 box vents on the back yard side of the roof about 3 ft from the ridge. No ridge vents, and nothing is powered.

The attic is probably 2000sqft and is high pitch roof.

EZ to answer, as most agree:

Get thee to a roofer ASAP to install
Continuous
Ridge Vents http://rb.gy/9yd5d
AND
Continuous
Soffit vents http://rb.gy/mhsjc

Some say gable vents are now controversial but have not seen the "turbulance" issues of the study.

More here: https://www.moneypit.com/


Also controversial have become the garage ceiling attic fans aka whole house fans that attempt to cool garage workers as well as the house attic at times .... some say only worth it in early Spring or late Fall.

AgEngr16 said:

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I have soffit vents about every 8 ft on the eaves, front and back of home along the red line. Seem pretty standard vent size 6x12-ish. There are 7 box vents on the back yard side of the roof about 3 ft from the ridge. No ridge vents, and nothing is powered.

The attic is probably 2000sqft and is high pitch roof.

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If I had your address I would do this for you, but based on your username, you are going to enjoy this part. We can calculate exactly what you need.

Go to google maps like you have already done. Zoom in, trace the perimeter of your roof line. Take note of that number.

Then figure out what the pitch of your roof is. You can download an app called 'Pitch Factor" and you can directly measure it or you can use the camera function and tilt your phone to match a gable end. If you have a 'high pitch' as you said, Id assume its more than 7/12.

Now you can go here:

https://www.spikevm.com/calculators/roof/slope-factor.php

Put in whatever pitch you find. Then get the pitch factor displayed. Multiply that by your measurement in square feet from google.

Then go here:

https://www.owenscorning.com/en-us/roofing/components/vent-calculator

This will tell you how many feet of ridge vent you need or how many roof vents you need. You can select the button for what you are after.

My guess if your attic vent situation is far less than what you really need. However, that calculator will help you decide if you even have enough ridge length to do ridge vent. You may need a combo of both, or swap out some of those existing vents with powered models. I suspect you have enough for ridge vent, probably only need 50-60 feet or so.

My point with all of this rambling is that your box vents (exhaust) are where your bottleneck lies, and increasing intake at your gables will help, but may not solve your problem by themselves. Gable vents can be both intake and exhaust, but I think ridge vent will take the convective properties of heat removal and make a more effective passive system.

I ran the calculator and it said I needed ~50 ft of ridge vent or 20 roof vents. Seems pretty obvious that the 7 I have are not adequate. Don't know anything about cost but I would assume I would be looking at a few thousand to install ridge vents.

I was planning to install the attic fan as an exhaust on the gable vent shown here. Obviously will need to cut the vent hole and install a standard louvre to keep the vermin out. The fan I'm looking at is rated for 1900CFM and would essentially be pulling at the ridge.

Thoughts? Bad idea? Better option?

Those ridges are perfect candidates for ridge vent. I would install ridge vent on every ridge on that house. I have done this on past jobs and the best improvement I saw was a drop from 155 degrees to ~ 137 degrees

Is that a diy job or get a professional? I'm a DIY guy for just about everything but roofing seems like a different animal..

If you have never done it before, its probably better to let a roofer do it. If you do ridge vent this is what I always use


https://www.gaf.com/en-us/products/cobra-rigid-vent-3

AgEngr16 said:

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I ran the calculator and it said I needed ~50 ft of ridge vent or 20 roof vents. Seems pretty obvious that the 7 I have are not adequate. Don't know anything about cost but I would assume I would be looking at a few thousand to install ridge vents.

I was planning to install the attic fan as an exhaust on the gable vent shown here. Obviously will need to cut the vent hole and install a standard louvre to keep the vermin out. The fan I'm looking at is rated for 1900CFM and would essentially be pulling at the ridge.

Thoughts? Bad idea? Better option?

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Gable end powered vents like you have will col the attic. Moving hot air out and replacing it with cooler air is the goal and it will do that. It will run dang near all day long starting at 9:30am to probably 10pm. Depending on where you are and pricing in your area, that amount of ridge should be less than $1,000. It can be DIY but I can assure you having a couple of qualified roofers do it is well worth it. My guys would start early before it got to 140 on the roof and have that knocked out pretty quickly. It's worth paying someone else to do it. You'll be needing to hump shingles, ridge vent, hammer, nails, and your circular saw up the roof with a steep pitch and trying to cut a slot in the decking…it's not hard in theory.

JP has a good product noted. All the manufactures make a good version but that one is readily available.

Your gable vent will probably work well but that's an active system and those motors don't last forever which means you'll be in this boat again sooner or later. Ridge vent is passive and has no moving parts.

Jason, is adding a ridge vent to a Decra tile roof as easy and costly as shingles? Guessing not.

It's a little more involved but not too bad. You just need to strip back the top course, if there isn't space, and then cut ridge…install proper decra batten and tiles. Are you certain it doesn't have ridge vent already?

Yes, for some reason my garage does but not top ridge of home. Since it is metal and has radiant sheathing it doesn't seem to get as hot as my previous home with shingles, but I would still prefer a ridge vent.