My house was completed slightly less than a year ago. It's a pueblo style with a flat roof. We've had snow lately, and when it started there was lots of high winds and dry, light snow. I was sitting on the couch when I got dripped on through the T&G ceiling. Since we just had our warranty roof inspection, the odds of a leak are VERY small. When I climbed onto the roof, it appears that a snow ramp had built up to the roof vent right above where I'm getting drips (see photo, left side of vent). It seems that snow has blown in and melted. Regardless, the roofing company is still coming out to check things out again.

I'm not worried about much damage internally, if any. It will dry fairly quickly and I'm not expecting this to happen all the time in this region. The blown-in insulation is anti-mildew treated, plus there is no drywall under the T&G.

The seems like it happened to just be a mashing of a bunch of rare factors, so I'm not expecting it to be a regular thing; the other vents did not have such snow ramps. Still, I'm thinking of mitigations:

1. Get pieces of metal ducting or convoluted tubing to make a ring "damn" around the vent. I would cut slots into them against the roof for drainage, but it would be a decent wind shield to keep the snow doing this again. The roof pitch is doubled the required code (1/2" per linear foot).

2. Add duct extensions to the vents to raise their height slightly.

Thoughts? Most of the stuff I'm seeing online concerning this issue is about peaked roofs.

If your home is still under warranty - make the builder complete the repair/adjustments.

quote:

Originally posted by Graniteguy:
If your home is still under warranty - make the builder complete the repair/adjustments.

It is, barely. I've already contacted them. It seems like this isn't really a problem with construction, though I'd consider it a design flaw. I'm just trying to come up with some easy fixes if the warranty thing gets complicated to the point of not being worth my time over an easy DIY fix. They've been building houses like this using these vents for this roof type in my area for years, so if this was a regular issue, I would have thought they'd use a different vent design. The type of snow we had isn't exactly common out here.

Its a problem if it is leaking. Make them complete the repair.

You have the right attitude, flesheating virus. Rare condition, though likely repeatable.

I like your solution #2, extend the (open) vent upwards with maybe an 12-18" extension, and assume that clears the ability of drifting snow to breach.
Ensure flashing boot at base of penetration is tight and well sealed.

Architect here, thats what I'd do. Easiest and least invasive with no unforeseen consequences that may occur with a semicircle wing dam solution.

Thanks! My #1 is to have the warranty/roofers do it all. Just trying to hash out some thoughts. It's my engineering side that can't let this stuff lie for someone else.

Replace the vent assembly with one that comes out on the downstream side....roofer should know where to get them...that wat snow doesn’t get blown into it.

No drywall under the T&G(?), what did they use for a vapor barrier?

Flat roof vent
https://www.google.com/search?...OhAU&biw=962&bih=601

quote:

Originally posted by Excam_Man:
No drywall under the T&G(?), what did they use for a vapor barrier?

Here are some construction photos. In the first photo you can see them applying the T&G over the fabric (?) that holds the blow-in insulation in. In the 2nd photo towards the upper right there is a rectangular hole, that's almost exactly where the water is dripping in. I believe that was one of the locations where they blew in insulation. The more square bluish hole to the right of it is a register.





So not only did the wind and the type of snow happen to be perfect to get blown into this one vent, but it happened to be just above one of the few blow-in holes for the insulation, so there was a hole in the fabric RIGHT THERE. Sheesh.

If you have a plastic sheet up there the water could be coming in from anywhere and just running down and out at that particular spot.

Do you have ductwork running in the attic space? Was that insulated? Is is possible that what you're getting is moisture forming from condensation as opposed to a roof leak?

That shouldn't happen. Put a space and raise the height of the vent by 6". But no amount of wind should ruin your interior ceiling either.

Extension. I had “Squirrel holes” on my roof they looked like yours. When we replaced it the standards was for ridge vents that work fine.

quote:

Originally posted by a1abdj:
Do you have ductwork running in the attic space? Was that insulated? Is is possible that what you're getting is moisture forming from condensation as opposed to a roof leak?

Here is the relevant section from the house plans. There is no attic space. It's a flat roof pueblo style house.

Raising the vents and having built in louvers or such design should resolve the problem.
https://roofvents.com/attic-ve...nt-12-inch-diameter/

With the combination of twisting wind and light snow, snow can find its way into many venting systems, be it ridgevent, roof vents, gable vents etc.
Several different systems have been redesigned due to problems with snow intrusion. I've been in attics where there was snow drifts due to the amount of snow blown inside through the ridgevent.

I don't see a vapor barrier in your diagram. Without one, your heating and cooling loads increase and your comfort decreases.

Basically, you have a wood ceiling, insulation and then a direct path to the air space, which is being vented to the outdoors.

no sheetrock between T&G and the rafters ? Never fly here need to have fire barrier.

quote:

Originally posted by XLT:
no sheetrock between T&G and the rafters ? Never fly here need to have fire barrier.

Not sure if that’s code out here. How would I check? I felt like my builder was pretty up on code, having brought up some other obscure code points during the build.