Should I have a ridge vent installed?

[The Money Pit]

Today it was 92* outside and I'm insulating the room above the garage. Just out of couriosity I took a digital thermometer to the second floor to see how hot it was up there. It will give me two readings because there is a sensor attached. One is for the inside temp and the other is for where ever you put the sensor. I stuck the sensor at ceiling height and left the other at eye level. It read 110* at eye level and 123* at the ceiling. I didn't go out until it cooled down to about 85*. I was wondering if I should have a ridge vent to keep the heat down. I will have HVAC for up and downstairs, eveything is going to be well insulated and nothing will be stored in the small space above the ceiling. I do have the "egg carton" styrofoam in between the insulation and the sheathing for air flow, but will that be enough?

 

[bmwpower]

Heat rises. Eve vents only work properly when there is a ridge vent or even better, an attic fan installed to **** the hot air out.

I vote for the ridge vent.

 

[dboat]

Heat rises. Eve vents only work properly when there is a ridge vent or even better, an attic fan installed to **** the hot air out.

I vote for the ridge vent.

I am totally with BMW on this one.. an attic fan or even some of those solar powered exhaust fans work great too. If you live in a fairly warm area, I would strongly consider something more active than passive when it comes to moving air out of the attic.
Have you even considered an insulated whole house fan? They are nice because on hot days, they can move a lot of air out of the attice, on temperate days, you can use them to move air out and keep you cool, plus if you get something odiferous in the place, it can move it out in short order..
Dana

 

[DynoDave]

It's amazing how hot attic spaces can get, isn't it? I'd go for a ridge vent. I have it on my home, and it is in the plans for my new garage.

 

[NHCharger]

Every attic space requires two vents. A soffit vent to draw the cooler air in and a gable end or ridge vent that lets the hot air out. I've been a builder for over 20 years and have seen a lot of roofs where the shingles begin to curl after a few years or the plywood becomes soft because of lack of ventilation. Proper attic venting is a must. Living in NH we only have one month of summer. In VA you must have many 90º days. A gable end vent with a fan would move a lot of air.

 

[mleichtle]

Unfortunatly vents won't help much with the heat. The only way to fix that is insulation, separating the living space from attic space. Still ridge vent is the way to go.

 

[The Money Pit]

Another good question is why don't more people have them on their houses? Do roofers not like to put them on?

 

[bmwpower]

Another good question is why don't more people have them on their houses? Do roofers not like to put them on?

Around here, they do. Newer houses almost always have a ridge vent, soffit vents. Also, usually an attic fan.

It's not any harder for a roofer to cap a ridge vent as long as the framers leave room for a ridge vent (which is easy to do too).

Not sure why older houses do not have them. This might be something new within the past 20-25 years or so.

 

[dboat]

Around here, they do. Newer houses almost always have a ridge vent, soffit vents. Also, usually an attic fan.

It's not any harder for a roofer to cap a ridge vent as long as the framers leave room for a ridge vent (which is easy to do too).

Not sure why older houses do not have them. This might be something new within the past 20-25 years or so.

When I had a new home built in the early 80's, it was a new technology then and on the cutting edge..
Dana

 

[bmwpower]

When I had a new home built in the early 80's, it was a new technology then and on the cutting edge..
Dana

That explains it. If any new houses in the area do not have one installed, it has to be that the builder is set in his old ways. Also, I'm not sure you have to do it by code.

I do know that the roll of that stuff (the name escapes me) that goes on the ridge is fairly expensive, like sub $100 for a big roll. Some builders might not want to spend the extra money.

 

[mleichtle]

Ridge vent has to be hand nailed, so theres more $ in labor beside the material, I used to get $.20 a fot piece work for installing it. Plus it requires a vented soffit, you cant have a clean, solid soffit, some houses built in the 60's don't have any overhangs to vent.

 

[OldCarGuy]

With the recent alarm over black mold, getting the most ventilation in attics is a must. Having full length ridge vents and all soffits ventilated makes more efficient air transfer in attics. At the same time an attic fan will help decrease attic temperatures that will put less of a load on air conditioner in the living space below.

 

[bahamasair]

Can you just add a ridge vent to an already finished roof?
After looking at a piece of the vent it looks to me like you just cut back a few inches on each side of the peak of the ridge. Is this right? I would think you need to add bracing to the ply where you cut back to as its no longer fastened to the ridge beam correct? Also what about hurricanes isnt it a good place for high winds to get a finger hold and start pealing back your ply? Id like to add one to my roof but dont want to have to do the bracing if thats needed and also dont want my roof to come off in the next hurricane. I have soffit vents and gable end vents but my attic is still too hot. Do you guys have a link to any of the solar vent fans mentioned and do they really move enough air to be worth installing? Im going to paint my roof white with that rubber roofing paint so that will knock off a few degrees. Sorry for all the questions Ive been wondering about the ridge vent for a couple of years but cant find much on the net about it.
edit: I found some info but all of the specs show cutting 7/8 back from the ridge. The roofs here have a beam down the middle of the peak and all the rafters are attatched to that so cutting 7/8 from the top will only be 1/8 past the beam. I guess the ridge vent wont work for me.

 

[The Money Pit]

My framers left a gap at the top for a ridge vent. I guess my roofer didn't put one on because it woudln't match my house since I don't have one on it. I'm sure it wouldn't be hard to put one on. I'm sure most builders don't put them on unless it's code or the client requests one. I didn't even think of asking to have one put on.

 

[dboat]

You should still be able to do a ridge vent.. some of the newer designs are able to handle hurricane force winds since those storms happen in areas where its hot and where hurricanes hit. I would just do a search on solar attic fans in google and see what you get.. There are different ones out there, some just replace your whirlybird attic exhaust and some need their own special hole made.. if you do have a gables at each end, maybe you might want to consider a gable fan (get them at your local big box store) and have it installed and hooked up to electric, then they use a thermostat to turn on and off.. these work well too..
Dana

 

[RAYJAY]

Another good question is why don't more people have them on their houses? Do roofers not like to put them on?

alot of time you can't see them there made of a mesh type and the roof shingles goes right over them .

the better air flow you have in you attic the longer your roof lasts and your cooling cost will be lower .

Jeff

 

[The Money Pit]

I guess the good news is that I can go back and have one put on later since my framer left a gap at the ridge. Thanks for the input guys!

 

[JMURiz]

How big of a gap at the ridge is needed, just wondering.

 

[bobbyd]

Ridge and soffit vents rely on convection to move air. Effective, but not all that efficient. Gable end fans controlled by a thermostat can change out the air in an attic right quick. Even a modest size attic exhaust fan can empty out an attic in a few minutes. Found a 16" fan with built in automatic thermostat complete with shutter at Grainger for <$200. It will move about 1000 CFM of air. For my 32'x32' shop with 6/12 pitch roof, the air would be changed out in about 5 minutes. Considering the cost of ridge vents and the labor to install, this seems like an attractive alternative.

 

[bobbyd]

****. I looked a little closer and found gable mounted fans that will move as much or more air for around $50, less the shutter which runs about $32. Definitely an attractive solution now.

 

[bmwpower]

How big of a gap at the ridge is needed, just wondering.

Minimum of a couple inches total, but max a couple of inches on either side of the ridge. Remember, ridge cap (the stuff you nail ontop of the brillo pad stuff, not shingles as previously discussed by someone) is what, like 6-8" wide, right? You don't want to cut too much since you need to nail the cap on.

 

[The Money Pit]

The only problem with my situation with a thermostat controled fan is that I would have no way of accessing it. It's a totally enclosed space. If anything happens to it like the motor going bad or something else, I would be out of luck. I would have to pull of siding and a gable vent to replace it. Although I might put one in my house attic.

 

[red vette mike]

I put a ridgevent in my nearly complete garge addition. They make a plastic type vent that is 4' long and about 2'wide. It fits over the top of the vent at the top of the ridge and the shingles go over that. The roofers charged $10 per each piece of the plastic vent sheets to put it on. It looks nice and I am sure that it lets a lot of heat out.
I have 3 power vents on my house plus ridgevents. I am not going to put power vents on the addition except for a small room where the compressor is housed.
Good luck.
Mike

 

[74-77Camaro]

For most homes, the cost of electricity for an attic fan is more than you would save in cooling costs inside your house, with the average insulation that is put into ceilings nowadays. Here in Texas, they like to put that blown insulation in at a depth that is supposed to give you an R-30. Most all houses I have been in the coverage is spotty, thin and uneven. If you use an R-30 faced batt, then lay an unfaced R-25 on top that, perpindicular to the joists, you will do a better job of keeping the heat away from downstairs.

It is extremely hard to keep the attic temps down. Ridge vents and continuos soffit vents are the best way, especially if the ridge vent is perp. to the prevailing summer winds so it will pull the air out. You have to keep the joists at the soffits clear to allow the air into the area. Whirlybird vents allow more air out than the usual capped vents that builders install.

The heat soak on shingles is tremendous, and it will still heat the air moving into it quickly. Temps over the last few days in Dallas have been in 99-98 range, it gets hot here. Aug will see weeks of 100+.

 

[The Money Pit]

I finished up the insulation today. Code requires R-30 in the ceiling and since I've got partially slanted ceiling I had to use R-30 for that also. Code is R-13 for vertical walls which I used downstars in the garage. I used R-19 upstairs because I didn't want to have to wait for 2' o.c. R-13 to come in because I would have had to special order it. Hopefully that will keep the heat/cold from getting out/in. I need an inspeciton then the sheetrock can go in!

 

[bobbyd]

For most homes, the cost of electricity for an attic fan is more than you would save in cooling costs inside your house, with the average insulation that is put into ceilings nowadays.

I'm not quite sure I agree with this, but maybe. However, the issue is not necessarily to save on cooling costs within the living space, but to extend the life of your roof. Unregulated temperatures on the underside of your roof can severly limit its useful life, by 50% in worst cases. Simple convective cooling from soffit to ridge vents cannot lower temperatures in an attic space as effectively as an active system. The attic fans I mentioned above, for less than $100, consume on average about 200W of electricity and can do a complete air change in a modest size attic, say 32' x 32' like mine, in less than 5 minutes. This is comparable to two 100w light bulbs on for a few minutes. Most of us wouldn't even notice the increase in electrical usage and would seem a small price to pay to add years on to the life of your roof.

 

[74-77Camaro]

Well, I had this issue in my 1500 sq ft house that I just moved out of. It had a number of rooms with 10' ceilings, so there was a 2' slanted ceiling around much of the perimter of the house. Bad thing is, the builder did not install the styrofoam eggcrating in between joists to allow the soffit vents to allow air in, so I only had about half the area of intake that I should of.

I installed a powered thermostat controlled fan behind the gable opening over the garage, and installed a louvered gable vent in the ceiling over my entryway to allow more air into the space, and some whirlybird vents. I installe dmore soffit vents where I could. I set the thermostat to kick on at 120 degrees. During the summer it would kick on about 10 am and run continuously until after midnight. I had enough airflow from the soffit with my mods, but it was not even airflow across the entire attic space as I would of liked.

The house I just moved into has much better soffit venting, and you can feel which direction the wind is blowing because you can feel the cooler air drafting. I hope to install a ridge vent in the next year or so that the wind will help pull more heat out of the attic without using electricity.

I guess my point is that the fan is going to run almost continuously using electricity, not just a couple of minutes. The heated plywood/shingles will radiate right back into the space instantly heating the air. It probably did help the roof, but made no noticible difference on inside temps. Now, when I replaced the blown insulation with batt, it did make a difference inside. The higher R value really helped cut down the heat transfer.

Just my personal experience fighting attic heat, YMMV.

 

[Jumpin Johnnie]

Venting your attic is for moisture control too. Yes it can reduce the temp in the attic but in a climate with both a heating and cooling season you need to remove the moisture in the attic to prevent mold and roof sheating failure. Power vents not only cost money to run but have a short service life.