Ridge ventilation at all peaks?

[dave houlihan]

Last week I had a roof installed on my ranch (low slope). Complete tear off and replace shingles. The way the house is built, the roof peaks are in the shape of a lower case "t". (Without the curly tail.)

The roofer installed ridge vents on the long part of the "t" but only the rear half of the cross of the "t".

In my opinion, all of the peak should ridge vents. Also, the contract stated: "Install cap over venting ridge to roof peak as per manufacturers specifications."

I would appreciate an opinion as to whether it is necessary to vent all peaks, and whether my contract requires the contractor to do so.

Thanks very much.

[dennism]

Necessary is a relative term. But it is a good idea to vent all peaks.
If it was in the contract to install ridge vent at all ridges, it should be installed.

Some ridge vents, usually plastic or fiber mesh, are meant to be covered/capped with the asphalt shingles.

There is a short video and info here that may help. Roof and Attic Ventilation

[Gunguy45]

Well, the part you quoted just says to cap the ridge vent, not how much vent should be installed. I agree that they all should be vented, for aesthetics if nothing else.

What other type of venting do you have? Continuous soffit? Gable?

You can't really have too much ridge vent (outflow), but if you don't have enough intake you really don't gain that much I don't think.

Whats the square footage of the attic space? How many feet of ridge vent do you have? What other venting do you have?

Take a look at post #2 in this thread. The links have some very good info.

Attic Ventilation

[dave houlihan]

Thanks for the responses. I have continuous soffit and also one gable vent. I would say of about 1900 sq ft of the part that has no ridge vent is about 250-300 sq ft. There is some restricted airflow in the attic between the unridged v. ridged area. I am quessing that there is about 55-65 feet of ridge vent. The no ridge vent area would add 10-15 feet.

I must say I read the contract wording a little different than Gunguy45, that is

"Install cap over venting ridge to roof peak as per manufacturers specifications."

whereby "cap over venting ridge" refers to the type of ventilation to be installed to the "roof peak". Any and all roof peaks.

In any event, would we agree that good construction practice would be to install the ridge vent at all peaks. When putting on a new roof, the cost 10-15 feet of ridge ventilation seems fairly marginal, so not putting it in seems foolish.

I haven't paid for this yet and if not significant I don't necessarily want to make an issue out if it is unreasonable to do so.

What would you do if you were me in this situation? I'm tending towards asking the contractor to put it in and/or possibly hold back a fair amount to get it done.

[Gunguy45]

1900 sf needs about 6.5 sf of vent area, evenly divided between intake and exhaust.

If you have 55ft of good ridge vent at about 18 sq in per foot, you have about 6.8 sf of exhaust.

Personally, I don't think I'd worry about it, but it's not a big deal to install some venting in the flow restricted areas. Pull off the existing cap, cut the shingles and roof decking, put on the vent and cap it. Prob less than an hours work.

We'll agree to disagree on the meaning of the quoted portion...lol.

I wouldn't get into it over specs of the contract, unless there is something that says "install ridge venting along full roof peak" or similar. Just express your concern about the restricted area's and ask that they put some venting in that area.

[dennism]

Agree with gunguy.

Ask for the remaining vent to be installed. Not a lot of work.

The contractor should know that a happy customer is worth that little bit of extra effort.

[dave houlihan]

Thanks Dennis M and gunguy. I'll let you know how it works out.