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Ridge vent mesh typeStop Ridge Vent Leaks
Causes & fixes for windblown rain or storm leaks at roof ridge

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How to stop hurricane or wind-blown rain leaks at roof ridge vents:

This article describes the cause of leaks into buildings at the ridge vent on both steep and lower-slope roofs during heavy winds, wind-blown rainy conditions, or hurricanes. We describe methods to cure a roof that leaks at the ridge vent and we list products specifically designed to resist stormwater entry at ridge vents.

This article series describes the best practices for roofing, attic, & cathedral ceiling ventilation to prevent attic or roof-space condensation mold contamination and to reduce building energy costs.

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Prevent or Cure Wind-blown Rain Leaks at Ridge Vents on Roofs

Fake ridge ventQuestion: how to vent a roof in high wind areas while stopping windblown rain-leaks

2017/06/06 Yolanda Ferrandi said:

We have a low sloped roof over our carolina room which has a raised vent at the top of the roof and ther roof slopes down from the vent at both sides of the vent.

Rain does not come in when we have heavy rain, however, with strong winds with last october's hurricane, the tape at the seam of our sheetrock ceiling in the carolina room opened, but still no water came into the room.

We've had heavy rain several times over the past month, but no water enters from the ceiling.

I believe the raised vent at the top middle of roof over carolina room has a problem only when we have a hurricane or very heavy winds, m before we have the ceiling tape re-sealed and the ceiling repainted, I need to have the raised vent
Problem fixed.

This question was posted originally at FLAT ROOF MOISTURE & CONDENSATION

Reply: causes of & cures for wind-blown leaks at ridge vents

Yolanda,

Indeed heavy wind and rain can cause water entry at a roof vent if the vent flashing designed to prevent that is missing, bent-down, or otherwise damaged or inadequate in height for your climate. You don't give your location, but if you are in a coastal area you may indeed need a different ridge vent.

If your home has an older-style conventional metal ridge vent, wind-blown rain leaks in high-wind areas are a well-known topic; leaks typically occur at the exposed roofing nails used to nail down the ridge vent and worse leaks when wind blowing rain up-roof overpowers the rather low (about 1" high) flange flashing along the lower edges of the ridge vent. These problems are likely to be more severe on lower-sloped roofs.

Your options to stop leaks at your roof's ridge vent during high wind and rain include:

Key Issues with Ridge Vent Leaks During Storms:

Ridge vents are frequently fastened down using ordinary roofing nails since these are normally handy. It is pretty common to find ridge vents dislodged or blown off during a hurricane (Figure 8). Even a partially dislodged ridge vent can begin to act like a scoop that collects wind-driven rain and directs it into the attic.

Most roofing manufacturers now make ridge vents that have passed wind-driven water tests. They are identified as having passed Florida Building Code’s Product Approvals or Testing Application Standard (TAS) 100(A).

Typically, they include a baffle in front of the vent tubes that provide the passageway for hot attic gasses to escape. This baffle is intended to trip any flow of wind and water blowing up the surface of the roof and deflect it over the top of the roof ridge.

Check Ridge Vents and Their Installation

When they are used, ridge vents are the last part of the roof to be installed. Consequently, the connection is readily accessible and frequently visible without having to pry up the edge of the vent cover top. Check the type and condition of the fasteners. If the fasteners are nails, replacement of the fasteners is in order.

If the vent has clear holes or slots without any baffle or trip next to the edge of the vent channels, the vent is probably not one that is resistant to water intrusion and you should consider replacing the ridge vent with one that has passed the wind-driven water intrusion tests.

Remedial Measures to Stop Wind-Driven Rain Entry

Replace nails with gasketed stainless steel wood screws that are slightly larger than the existing nails and, if possible, try to add fasteners at locations where they will be embedded in the roof structure below and not just into the roof sheathing.

Close spacing of fasteners is recommended (e.g., in the range of 3 to 6On center, commensurate with the design wind loads). If the ridge vents are damaged or are one of the older types that are not resistant to water intrusion, they should be replaced with vents that have passed the wind-driven water intrusion tests - FEMA (2009)

Ridge Vent Leak Prevention Research & Products

Ridge vent closeup showing mesh

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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2019-06-18 14:12:38.891301 by (mod) -

Mike,

These are minor, common finishing details on roof ridges. At the lower ridge that abuts the lager higher roof,

You might apply roofing mastic under the corners of the shingle lapping the top of the abutting ridge.

On the upper ridge at the end, because we're at the highest point on the roof where there is no accumulated run-down quantity of water during rain, the leak risk is very low. Still it's good to seal any exposed nail heads.

Where there exposed nail heads, when the roof surface is dry and clean, I like to use a silicone sealant as a more-durable seal than mastic where it will be exposed to sunlight.

On 2019-06-09 03:52:11.906182 by Ron

Reroofing a north-south 3/12 sandwich roof, no attic. Currently east-west ridge vented with baseball sized soffit vents every 16 inches on both north and south soffits. Roofers want to upgrade the ridge vent and several are offering roof exhaust edge vents. Roofers disagree about whether they should be used. What is your opinion on these? What would be your recommendations for best venting options overall? Would you replace the ridge vent or soffit vents, which would incur some expense?
We are in Denver CO, where we have extremes of snow and cold weather, hail, and heat and warm weather. High humidity and mold are not a factor in our dry climate.

On 2019-05-31 15:40:05.765699 by steve

I should have been more specific, but the leak is coming from the OLD flat roof where the exising vent comes up. And moisture, be it condensation or maybe the ridge cap, is getting through the new wood/metal and seeping in. This ONLY happens with deep snow, not when it rains! In a way I am upset with the roofer knowlingly NOT extending the soil vents through the upper added-on. The previous roofer did not extend the soil vents so this next roofer figured he shouldn't have to! So it is hard to determine if it's condensation or ridge caps or vent boots, or a combination of any three. Thanks.

On 2019-05-23 by birdman

How do you bend a metal roof ridge cap where a smaller gable roof meets a bigger gable roof so that the smaller gable roof's ridge cap goes under the bigger gable roof's steel roofing panels?? Use a hammer and pound the love out of it? see red circled area in pic. Need close up detail and how to bend. Thank you.

IMAGE LOST by older version of Comments code - now fixed. Please re-post the image if you can. Sorry. Mod.

This Q&A were posted originally at InspectApedia.com HOME

 


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