Attic venting in Florida?

[Hot Rod Grampa]

Hi all. A couple of years ago we bought a house in sunny Florida and are slowly fixing the place to make it ours. Up north we vent the attic well. I have seen references here about doing it differently. Last winter I started installing vented soffit on one end of the house. The ridge cap is the plastic style with shingles as a cap. We are here this week addressing a water leak in the bathroom and I went in the attic and it was beyond hot. So what is the consensus?

 

[driftpin]

Look at the code version adopted by your local jurisdiction and follow it for the venting requirements.

You should be able to find a link on the building dept web page.

 

[mike93lx]

venting will not make the attic cool, just less hot. even in MA, I can't spend much time in my well ventilated attic in the summer. There is still a huge black panel above you absorbing a ton of heat.

if I turn my attic fan on, it cools down quite a bit, but warms the house up.

 

[Hot Rod Grampa]

I agree it will never be cool. The nice guy at the county gave me pages to read. Did that. I am asking for input as to what works best. The original soffit has oval holes about 3"x6" with a metal screen over it. All that has been painted at least two one three times, including the screen so not much air passes through. This winter I plan on adding insulation to the attic. Hopefully it will help ease the load on the AC. But increasing attic ventilation would seem like a logical next step.

 

[johnyg]

im in boca and had the standard sofit vents and r-15 cellulose. when i cut out the gable for vents the rush of hot air out was amazing.i also brought up the cellulose up to r-30 and it seems to keep the a/c from running as much. the school of thought now is spray foam on the sheathing to make the attic an insulated space.to rich for my blood.p/s cover the gable vent for hurricane protection...good luck.

 

[kbs2244]

The concept is the same no matter the location.
You need to let the hot air out.
And it needs to be replaced with cooler air.
To do that you need exits at the high point and inlets at the low.
Your ridge vent is a start.
Now replace the soffit ones.

Insulation on the attic floor will help the AC.

 

[Jinks]

Uh, ridge vents........think about 'em. I never had one till I bought a weekend place near Daytona. Didn't really give it much thought. In '04 we had three hurricanes go through. No real serious damage, lost a few shingles, lots of limbs down, etc. Except for the weekend house. That damned ridge vent let a LOT of the horizontal rain in & left a wet ceiling all the way across the house. Took a lot of work to fix that.

When we built our retirement home (about three miles from the beach cottage) I opted for regular roof vents & vinyl vented soffit vents. Haven't had any water damage since.

 

[fdtrucks]

As Jinks stated, ridge vents in FL are a terrible idea. I remember '04 quite well. Everyone I knew with a ridge vent had water damage. Also tropical storm Fay in '08 proved the point again to the people that re-roofed in '04 and did another ridge vent. The spray foam that was also mentioned is growing in the residential world. Its a little different product than what most think of in the walls. They are putting it on the underside of the sheeting for two reasons. First is to reduce the thermal load from the sun beaten roof, second is because it is water tight, so it adds another layer of protection if you loose shingles in a storm. A buddy of mine applied it on the exterior and it looked like a snow blanket, but his 1960's concrete block 1,300 sqft house with jalousy (sp) windows only cost $30 a month in electricity to cool. Plus he got a nice insurance discount, and a rebate from FPL.

 

[matt_i]

I lived in Atlanta for a few years, I had mushroom vents with powered fans underneath, in my house. They came on with a pretty simple thermo-switch as a packaged unit.

I had great plans to automate the fans with a 24 hour timer and/or an actual thermostat I could adjust, but these were never realized. I think a person could get a lot of cooling with soffit vents, closed ridge, powered mushrooms.

Whether it made a noticeable difference in the house temp I was hoping to find out, but usually moving air is less expensive than moving heat, from an electricity perspective.

 

[Hot Rod Grampa]

Thanks for the input. I guess I have to re think the ridge vent. Do the electric mushroom attic fans keep the hurricane rain out well or are they prone to leaking? Maybe just having all four soffit vents working will be enough to move the air. We just got back to upstate so I will do some more research.

 

[Bench o Rama]

Thanks for the input. I guess I have to re think the ridge vent. Do the electric mushroom attic fans keep the hurricane rain out well or are they prone to leaking? Maybe just having all four soffit vents working will be enough to move the air. We just got back to upstate so I will do some more research.

Check out the Florida Solar Energy Center. They do Florida specific research on various ways to minimize heat gain, including covering attic ventilation:

http://www.fsec.ucf.edu/en/consumer/buildings/homes/faq.htm

There's lots to read, it can keep you busy for a while!

 

[Jinks]

Thanks for the input. I guess I have to re think the ridge vent. Do the electric mushroom attic fans keep the hurricane rain out well or are they prone to leaking? Maybe just having all four soffit vents working will be enough to move the air. We just got back to upstate so I will do some more research.

The mushroom vents have a contained footprint instead of being stretched the length of the roof like ridge vents. You can either place a catch basin (if you have access) or put a cover over them when you close up for the storm. They also come with solar cells & run for free.

 

[6768rogues]

I don't typically see ridge vents in FL, but I do see large regular box type roof vents, much bigger than we find in NY.

 

[davidlee]

I live in the panhandle of Fl and I have ridge vents on the house, garage and shop. I have not had any problems with them. They went through hurricane Ivan in 04, a cat 4 storm.

 

[Hot Rod Grampa]

I truly appreciate the input. I will look into the mentioned resources. Thank you.

 

[Chaznsc]

venting will not make the attic cool

Technically, there's no such thing as cool, only the absence of heat. There is no dark, only the absence of light.

 

[Scott H in Wheaton]

My ranch style home has continuous vented soffit on front and back, and ful length ridge vent on top.
On a 95 degree day the attic is about 110.

On the same day, other attics I have been in are around 130-140.

If ridge vent leaks it is the wrong brand of ridge vent. GAF Cobra Ridge Vent is probably the most thoroughly tested product out there.

 

[Hot Rod Grampa]

I agree the attic needs to have proper air flow to be vented correctly. Ma

 

[Hot Rod Grampa]

Oops! Fat finger on wrong key. Many houses I have looked at only have three or four metal vents near the ridge on the back of the house. Maybe a square foot each. No way that has the ability to flow the volume of air the attic requires. Might meet code but common sense says it won't work well. Thank you for the continued responses.

 

[lakeroadster]

When you are hot.. do you wait for a breeze, or make your own?

These folks can help: https://solarroyal.com/ventilation-101-basics/

 

[ard]

In the summer it is hot and dry here. 30-40 days over 100f... So ymmv

I vented the attic, continuous soffit vents, the vents at the peaks. (Hip roof, so ridge vent too short, not enough.)

A also put in radiant barrier under the roof deck, wit 1-2 inch of air space between barrier and ply. This resulted in DRAMATICALLY lower air temps. AC guy was able to drop from 5 to 4 ton for the upstairs unit. He was shocked at the temps in the attic when installing the system. Made a believer out of him. (This was 20+ years ago, the general contractor thought I was nuts.)

IMO it is a rare situation where you would NOT ventilate the attic in a hot climate.