comp roof and venting

[Guest]

I'm getting estimates for a new roof. My question is I've been told by a few that the pitch is to low for ridge vents. but others say it's ok and they are the best way to go. They are more expensive .. so are they just trying to get my money???

I'm just outside of Seattle, Wa.

The pitch is 2:12.

Also does any know about ice and water shield instead of felt underlayment?

Thanks
Amy

[JD]

Hi Amy,

Most ridge vents, whether rolled or in strips will require a minimum 2.5 in 12 pitch, since that is the minimum warranty pitch for composition shingles. Many state a 3 in 12 minimum. Owens Corning has a ridge vent product that says it can be applied at 2 in 12 though. I have used Owens Corning vent products, but not this exact product.

VentSure® Corrugated Strip Low Profile Ridge Vents
http://www.owenscorning.com/around/vent ... ?ProdID=56

My opinion would be that if you have an older home with cathedral ceilings, a ridge vent would be a good idea. The homes I am talking about will have 2x6 roof rafters with roof sheathing on one side and ceiling panels on the other. No cross ventilation at all. If moisture gets trapped between the rafters, the vapor accumulates at the ridge where it can dry rot the roof sheathing and the rafters where they meet the marriage beam.

On newer homes with cathedral ceilings, they are using a framed truss which allows cross ventilation. On these roofs or any home with flat ceilings, you may be better off with gable vents.

Using ridge vents with the 2x6 type rafters is kind of like a desperation afterthought. After many homes had water damage due to lack of venting, ridge vents was the best solution the manufacturers could come up with, which did work in most cases. But the ridge vents are actually made to work with eave vents for a total system. Without the eave vents, we are counting on the ridge vents to work in more of a venturi fashion than a flow-through ventilation unit.

I see you are from Bothell. I lived in Kenmore and Lynnwood for many years. Nice to meet you. Is that French restaurant "Georges" still there on Bothell Hwy?

JD

[Frank]

I'm getting estimates for a new roof. My question is I've been told by a few that the pitch is to low for ridge vents. but others say it's ok and they are the best way to go. They are more expensive .. so are they just trying to get my money???

I'm just outside of Seattle, Wa.

The pitch is 2:12.

Also does any know about ice and water shield instead of felt underlayment?

Thanks
Amy

Make sure your contractor is registered and get all warranty paper work. Your contractor in WA state is responsible for the permit. He also by law in WA state must by the permit or could be fined. I know I live in Oregon.

[Guest]

Don't worry .. that's what I do for living. I work of a drywall supply company and I'm the one that checks everyone's license. I'm also going to require a lien release before final payment.

I've looked at the codes and I am going to stay with the can venting.

Now I just have to decide which color I want. I'll be painting the house next year ... I think I'm going with Mountain Timber.

I'll post pictures ...

Amy

[Jim from Canada]

Check out this ridge vent system. I really like it as the cupolla keeps the vents above the snow on a low sloped roof.
http://www.ventilation-maximum.com/eng/indexen.htm


Jim