Roof Ventilation FAQs-2

Roof venting questions & answers: FAQs set #2.

This article series why roof ventilation is needed on most buildings, how good roof ventilation is designed and implemented, and why a functional roof venting system needs both intake venting at the eaves or soffits and outlet venting at the roof peak or ridge.

Roof Venting FAQs

These roof ventilation questions & answers were posted originally at the topic home page: ROOF VENTILATION SPECIFICATIONS - that's a good place to review the topic and to find advice on just how much venting is needed and where it should be placed.

Also see our index to all Q&A about roof ventilation problems and solutions, found at ROOF VENTILATION FAQs

Article Index

• x
• [We're in process of editing the Q&A below - Ed.]

...

Tell me how to cut in venting slots in a soffit

Hello everyone, a little help please. Our soffit vents were never cut out. Only 3 of the 20 or so little wholes are showing light. How can I correct the wood blocking the soffit? On 2018-02-03 by Stefany Bushey

Mod reply - here's how I do it

Stefany

Typically for a plywood soffit covering we use a small circular saw, overhead (with eye protection etc) to cut a slot that extends the full width of the home. Your ncontractor will cut out a strip of width to just match the plastic or aluminum perforated screen insert for soffit venting that you'll find at your building supplier.

Of course one needs to inspect the soffit and attic to be sure the air path is not blocked by insulation - you might need to add baffles to continue the air path over the wall top.

How do I get attic venting if my house has no soffits?

My house does not have soffits, does have ridge vent. 2nd floor has 2 dormers with one vent each in the eaves.

The area is unlivable in high summer and winter, no installation on about half the area including both dormers. Shingles are being replaced in about a month or so, what should I do for adding venting. On 2017-08-21 by Steve S

by (mod) -

Steve

We describe some venting options when there's no usable soffit - at ROOF VENT if NO SOFFIT

Worried that soffit vents will draw humid air into the attic

I have gable vents and no intake vents in soffits. I live in a humid climate by the coast in the Northeast.

I have no mold in the attic or moisture. Sure it gets hot in summer but I can open up the attic excess panel and get the proper air flow to ventilate the attic.

My concern is that using continuous intake soffit vents will draw humid moisture into attic.

The house has been here for more then 50 years without problems except for accumulating heat during summer and shingles because I was not opening excess panel to attic for intake flow. Should I just keep doing what I am doing to prevent moisture from entering from outside? On 2017-04-26 by Rod

by (mod) -

Rod

Good points and good question.

We need the right ratio of intake and outlet venting for attic venting to work on its own; IN summer in most homes, even in a hot climate, the attic is hot as all getout, so drawing air in at the soffits and venting it out at the eaves ought to cool and dry the space;

In other words I'd not expect moisture to condense OUT of the incoming air as long as the attic is hotter than the incoming air itself.

You can keep doing what you've been doing; but in my OPINION gable end vents will never move air up under the lower areas of the roof, especially closer to the center of the structure; optimal venting cools and dries all of the roof underside surfaces.

Contractor wants to add two power vents low on roof to "fix" our too-hot attic!

I have discovered that the specifications on our home calls for 11.63 sf of venting for a total roof area of 3490 sf, in
austin Texas. This breaks down to 5.81 sf of soffit and 5.81 of ridge vent, or 142 lf of soffit vent and 47 lf of ridge vent to meet these requirements. However, we got 263 lf of soffit vent and only 22 lf of ridge vent.

We have a hot attic! Contractor wants to add two power roof vents fairly low on the fron of the house, but I'm affraid this is not the right solution. (We can't add more ridge vent, because no more available ridge!) Can you give me another solution? On 2017-04-09 by William

Explanation and advice by (mod) - don't do that

Power vents can increase the air flow through the attic but will of course not vent the roof nor attic space uniformly.

I would absolutely NOT simply count linear feet of soffit intake nor ridge outlet venting; one needs to actually look at the vents, notice obstructions, perforated screening, or other things that reduce airflow.

Typically we can increase the soffit intake venting by moving from simple vent strips to complete-perforated-coverings of the soffit underside.
That might feed enough air that if your ridge vent is also not obstructed - say by too-narrow cuts into the roof or by being blocked by roofing felt - to get the attic venting working.

How can I confirm that air baffles are working to vent a CapeCod Roof with Dormers?

I have a 30-year old cape cod with dormers on the front. The original construction used bead board soffit baffles, and I'm concerned that they have collapsed in many locations. They're under 3 1/2 " insulation, down the sloping wall to the soffit.

The entire length of the rafter from the soffit up to the point where I can reach it in the Attic is 8-10 feet.

Any suggestions for checking to see if these baffles are still working and there is air coming up from the soffit? If not, is there any kind of retrofit solution to open them up, e.g. some kind of rigid tubing or box structure that could be run down the underside of the roofing to form a more rigid passageway? Thanks for any experience you can provide. On 2017-01-12 by bugsy

by (mod) -

Bug

If you can't see daylight in the attic then the insulation is blocked.

If you can't see into the attic to make that inspection, and if you live in a freezing climate, look at the pattern of ice dam formation on your roof. No venting means more ice.

Yes there are rigid baffles that can be inserted between rafters from either side: outside or in the attic.

Or in a labor-intensive approach you can use a combination of furring strips nailed to rafter sides and solid foam insulation to give a 1.5-2" or more air space under the roof sheathing.

...

Continue reading at ROOF VENTILATION SPECIFICATIONS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ROOF VENT SOFFIT + RIDGE NEEDED
• ATTIC CONDENSATION CAUSE & CURE

Suggested citation for this web page

ROOF VENTILATION FAQs-2 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING VENTILATION

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Questions & answers or comments about attic moisture, condensation & ventilation: why are both soffit intake and ridge outlet needed?

	HOME	ABOUT	ASK a QUESTION	CONTACT	CONTENT USE POLICY	DESCRIPTION	POLICIES	PRINT	PRIVACY
	© 2026 - 1985 Publisher InspectApedia.com - Daniel Friedman