Getting New Roof. Should I Get Ridge Vents Also?

[John Galt III]

Hi,

I'm in the negotiating stage of getting a new roof put on my townhouse. The contractor, who is well known and reputable, and very busy, is hyping ridge vents. To install a ridge vent requires cutting long slots into the plywood near the ridge, to allow air ventilation, and then covering the slots with the "ridge vent cover". I'm concerned about rain or snow getting in. Plus it just looks "wrong" to have this extra stuff on top of the roof.

My current roof does not have a ridge vent, and is doing just fine. No excessive heat in the attic in summer. I have soffits and a gable(?) vent for air flow.

I read that roofers like ridge vents because they are easier to install than the conventional shingles up on the ridge, and they are a money maker for them.

My search of the net revealed that ridge vents are almost never a problem, as far as rain and snow getting in, if installed correctly, but simply may be unnecessary in many cases.


Anybody get a ridge vent and has it been OK?


Thanks

 

[Dimsumkid]

If you're not having any heat buildup problems and have good ventilation in the attic, you probably don't need one. I added one to my house (did the work myself). My soffit vents were 4" x 8"s, but when I checked the openings, they were only cut 2" x 5". I also changed the soffit vents to 8" x 16" instead and increased all the openings. Before the ridge vents were installed and changing the soffit vents, on a sunny 80 degree day, attic temps were 120+ degrees. I haven't had any issues from snow or water penetration from the ridge vents.

 

[RunningBum]

Yes, I've not had a problem that I've noticed, even with 20" of snow with high winds twice, and 30" in another storm. It helps keep things drier as well as helping with heat, but I can't say how necessary they are.

 

[JoeWras]

They are good if you are in a hot climate, and have good soffit flow. They are much more common in the south and make a lot of sense here.

As for looks, it is OK. My house was one of the early ones to get these retrofitted. Now, every house has them. All new houses here have them. It makes sense in this tough climate. It could never be as classy or classic as straight ridge shingles.

No rain or snow problems, ever. I've seen much worse problems from standard rooftoop vents. If you have rooftop vents, go ridge instead. Sounds like you are OK with just gables.

Finally, I don't think it is that much easier for the roofer. In my case, they actually nail shingles over the vent. If anything, it is harder and takes more skill to not have ridge shingles uneven.

 

[timo2]

I had a ridge vent put last time I re-shingled. It's been about 10 years since then, and everything has been fine. Do you currently have any other existing vents in your roof?

In my case, it is a 1972 edition house. It had 3 layers of shingles on it. and a small roof leak. And there were no modern vents in the roof. just a turbine and one dormer style vent. When the roofers had removed all of the old shingles, it turned out that 6 of the plywood sheets on the roof needed replacing, mostly because of condensation from inadequate roof venting.

So here is what the roofers did: on the part of the roof over a cathedral ceiling, that's where they put the ridge vent, because nothing else would fit. on the part of the roof that has an attic below, they put three typical basic roof vents. Then they put little gable vents all around the sides of the entire roof. They removed the wind turbine. Additionally, I put in a solar powered vent fan in the dormer style vent. That was 10 years ago, and have had no problems since. When we re-insulated the ceilings a few years ago, there was no sign of any weather getting in.

 

[eytonxav]

This is one of the most efficient forms of ventilation and should not cause any intrusion problems if properly installed. As mentioned, you need to have sufficient soffet vents to get the proper flow going, but there is no such thing as too much ventilation regardless of climate. We've had them on our house for many years and the low profile ones do not look bad at all.

 

[Texas Proud]

Just be careful.... if you put them in you probably have to close off whatever you have now...

IOW, if you have whirlybirds close to the top of your roof, putting in ridge vents will have air flowing between the whirlybird and the ridge vent... not doing much for the rest of your attic...

I do not see where it would save any time on putting on a ridge if you do not have them.... at least on my old house they still put shingles on top of the ridge vents...

 

[rodi]

We have them and my husband (architect) insisted on them. In hot climates they extend the life of the roof (according to him.)

Since we live in So. Cal (land of wildfires) we made sure to have insect size stanless steel mesh (super small openings) to prevent against embers in a wildfire.

 

[JOHNNIE36]

Ridge vents are very common here in Florida. In fact, almost all the homes in my area have them and they are tiled roofs. Other areas with shingled roofs have them also so the type of roof you have doesn't make any difference.

I'm going to hitchhike on this topic and start another thread about replacing roofs.

 

[Tyro]

As stated by others, what's important is that a roof get ventilation. If it's got sufficient ventilation, there's probably no need for ridge vents; OTOH, if ventilation is insufficient/non-existent, they're a good inexpensive way of accomplishing it.

We had lousy ventilation, which did shorten the life of our last roof (shingles deteriorated, sheathing rotted in some places) so we had ridge vents installed the last time we re-roofed. It did not, IIRC, add that much to the cost, and we've had no problems resulting from them. FWIW, we're in the snow belt.

Tyro

 

[travelover]

As stated by others, what's important is that a roof get ventilation. If it's got sufficient ventilation, there's probably no need for ridge vents; OTOH, if ventilation is insufficient/non-existent, they're a good inexpensive way of accomplishing it.

..............Tyro

+1. Proper ventilation can be accomplished several ways, just make sure it is accomplished. A well ventilated roof lasts longer and also is cooler in summer and has less chance of ice damming in a cold climate.

 

[BTravlin]

Heat rises and ridge vents are good at expelling almost all heat accumulation since they are at the highest point in your roof system. Just replaced my roof and had them put in for just slightly higher cost. Roofer, home inspector and insurance adjuster all recommended them.

 

[Brett_Cameron]

I had them installed last year during roof replacement on the contractor's recommendation. The cost was low, $150 compared to $10k cost of roof replacement. seem to work well.

 

[gauss]

I specifically opted not to put in a ridge vent the last time I had the roof replaced.

I have a low profile ranch with a 5-12-13 roof pitch. I personally did not care for how the ridge vent would look from the front of the house. It was purely an aesthetic decision. Instead, they put a bunch of vents on the backyard side of the roof. The house was built in 1957 and is located in the industrial midwest.

-gauss

 

[gromit]

Be aware that installing the ridge vent leaves a layer of sawdust in the attic below where the roof cuts are made. Sawdust that falls onto boxes or plywood attic flooring is easy to clean up, but sawdust on top of blown in insulation is not. The line of sawdust is not too wide, but still messy.
That said, I still like having a ridge vent here in the hot South.

 

[JakeBrake]

Personally, I don't like the looks of ridge vents. I won't have them on my house. We have non-electric turbo vents that seem to do the job. The turbo vents are not visible from the front of the house. We do have a very steep roof.

My roof was replaced in 2008 after a hail storm. My roofing contractor at the time also did not like roof vents. My roof was previously replaced in 1992 after we were hit by a tornado. The house was built in 1984. I don't think I've ever paid for a roof replacement other than my insurance deductible.

Both time the roof was replaced, the roofing contractor removed everything down to the roof sheathing.

 

[scrinch]

We've had ridge vents on our house in northern California for about 10 years, and they seem to have worked well at keeping the roof cool. The one issue we had with them was bats coming into the attic space through the small gap (4'x3/4") at the gable end of the roof at the ridgeline. Once I figured out what all that noise up there was, I just waited for them to go out one evening and then plugged up the gaps with plastic netting. No more bats!

 

[John Galt III]

Thanks for the replies!

Timo2, I only have 2 vents on the roof. One for the upstairs bathroom fan and one for the sewer vent pipe.

Nobody mentioned higher heat bills in Winter, so I guess that's not a significant concern, if there is ample insulation on the attic floor.

 

[travelover]

Thanks for the replies!

Timo2, I only have 2 vents on the roof. One for the upstairs bathroom fan and one for the sewer vent pipe.

Nobody mentioned higher heat bills in Winter, so I guess that's not a significant concern, if there is ample insulation on the attic floor.

Neither of these provide ventilation for the attic space. If you get a ridge vent, make sure they also install soffit vents for incoming air.

 

[timo2]

Thanks for the replies!

Timo2, I only have 2 vents on the roof. One for the upstairs bathroom fan and one for the sewer vent pipe.

Nobody mentioned higher heat bills in Winter, so I guess that's not a significant concern, if there is ample insulation on the attic floor.

Regarding insulation, I live in Colorado, so did think about the cold air in the attic. but heat lost to poor insulation is still going to be lost, roof vents or no. and I'm thinking that poor insulation and no vents actually would increase the amount of condensation under the roof? my ceiling insulation that I replaced in 2010 was still the original 1972 insulation, so it was definitely bad.

I do have a solar attic ventilation fan that runs whenever the sun is out, winter and summer (for 9 years so far). all the insulation people I got estimates from liked it. That has not affected my winter heat bills either.

 

[John Galt III]

Neither of these provide ventilation for the attic space. If you get a ridge vent, make sure they also install soffit vents for incoming air.

Correction! I was wrong about the vents. I have 2 silver "cake box" vents, one on each slope, that just open into the attic with no hoses attached, and one tube type vent on the front slope (sewer vent?). Also, a gable vent in top of the gable. Looks like all are passive. Never hear a fan running. Also, I have lots of soffet vents in the eaves. I was up in the attic 20 years ago, and saw them. Today I rigged up a mirror on a stick and looked around. It looks like my bathroom fan just vents into the attic through a tube that sticks up about 5 feet above the insulation. Using my mirror on the stick I could not find the "sewer vent" or "vent pipe". Will have to get into the attic again somehow, through that small square access hatch ...... ugh...

 

[Dimsumkid]

You need to make sure your bath vent doesn't just exhaust directly into the attic, if so you need to finish it through the roof or the soffit. You're adding moisture in the attic whenever you run the bath fan which promotes mold growth. You should check all your soffit vents to make sure they're not clogged with dust, debris and loose insulation. If you decide to do ridge venting, you will need to cover up the gable vent to help promote proper airflow from the soffit to ridge vents. Otherwise, you'll just be pulling air from the gable to the ridge when isn't what you really want to do

 

[samclem]

Ridge vents are fine. They are not functionally any better or worse than standard roof vents placed near the ridge, but some people like the look a bit more.

If a home has standard roof construction (an insulated ceiling over the top inhabited floor with a roof over that), then the attic space definitely needs to be ventilated effectively. That means soffit vents (so air can get in) and vents up high (ridge, gable, "box" etc) so the hot air can get out. This is important in hot climates but also very important in cold climates, else the moisture in the warm air from the home will condense on the cold roof/framing and mold/rot will result. Gable vents can be "okay" for the upper vents, but they often need to be very big in order to get the job done (see math below).

How much ventilation is enough? One rule of thumb is that the Net Free Area (NFA) of the top and soffit vents combined should equal 1:150th of the attic size. The NFA is shown on vents of all kinds and accounts for the obstructive effects of screening, bracing, etc: The NFA can typically be about 1/2 of the actual area of the hole for the vent. So, a 2000 sq foot house would need 2000/150=13.33 sq feet total NFA of soffit and top vents. That's about 6.75 sq feet NFA for top vents and 6.75 sq feet NFA of soffit vents.

Soffit vents: Having vents in the soffits does little/no good if the path of the air is blocked by attic insulation. It is important to have trays installed or take other steps to assure the air can get up into the attic.

Today I rigged up a mirror on a stick and looked around. It looks like my bathroom fan just vents into the attic through a tube that sticks up about 5 feet above the insulation.

That's a bad setup. Even worse: I've seen clothes dryers vented that way, rather than going outside. Every load of laundry= a gallon or two of water piped up there to the attic to cause mayhem (condense on the roof/truusses in the winter, condense on the ceiling and add to the heating load in the summer). Bathrooms, clothes dryers, stove hoods should all be vented to the outside through a vent in the roof, wall, or (less good but far better than the attic) through a dedicated vent out through the soffit.

For what it's worth.