I hate water!

[lml999]

We've had ongoing issues with humidity in our attic, and now I think I know why...

Some background:

We bought a traditional colonial, in southern New England, with an unfinished attic two years ago. The house is 23 years old, the roof is about 5. The fascia boards have full drip edge venting and a ridge vent runs the length of the house. No soffit vents.

On top of the FG insulation in the attic floor, we blew in additional cellulose insulation. The installers did a mediocre job of installing the plastic chutes between the joists, and used smaller ones than I would have used.

I had the gutters cleaned and gutter guards removed. The gutters were clean, no buildup. I thought the gutter guards might have been blocking some airflow to the drip edge vents.

Over the course of the winter, I noticed some frost on exposed nails in the attic. There's also some light mold on an area of the inside part of the roof, which I thought was caused by a poorly sealed attic ladder.

I also noticed drip lines in the cellulose. I thought it lined up with the exposed nails.

I've also noticed a couple of places on the second floor (below the attic) where there's some light water staining on the celing. Not much, and most of it is by the ceiling/wall intersection. There's at least one area that's nowhere near the wall.

However...

This weekend we had heavy rain and wind. I went back up to the attic to check this morning and found that it's really humid. I also noticed more drip lines in the cellulose, and they align to the ceiling joists. Interestingly, they also align to the plywood underlayment joints.


In the attached photo, you can see the drip lines in the cellulose.

Most, perhaps all of the dripping is on the northeast side of the house, which doesn't get much sun. I assumed that this was a winter issue due to less heating of the northeast side versus the southwest.

So here's my hypothesis:

Windblown rain, usually from the north, gets in past the ridge vent and travels down the roofing joists. Some gets diverted at the plywood joints and travels horizontally. Some drips down as it travels, and some ends up at the bottom of the joist, staining the ceiling.

So...it looks like I need to get someone to inspect, and probably replace, the ridge vent.

And to improve the air flow, I probably need to clear out the insulation at the lower edge of the roof and install larger air chutes. Because of the standing cellulose, that's going to be a PITA.

Does this make sense, or am I all wet?

 

[blades]

yes. On right track. I have ridge vent we get strong winds stuff gets blown in it . it is lined with some sort of black fabric mesh , which in some areas is shot. get drip lines from that. Roof is a 12/8 so I can't reach anywhere near that ridge. Vent panels got a few that need to be reset. These are the full 16" width muti v shaped ones. I haven't noticed excessive moisture in my attic. i have straight cellulose up there.

 

[peakbagger]

Interesting, not the first time I have heard of a ridge vent leaking and inadequate air flow out the ridge vent leading to a damp attic. There are many brands out there and I think some are better than others at keeping water out and air flow adequate. I have the ones that look like it was cut out of a stack of corrugated plastic that looks like cardboard. Contrary to popular wisdom I also have two gable end vents one on the end of the house with a prevailing wind and the other on the lee side. Folks claim all sorts of evil happens with a ridge vent and gable end vents but IMHO, the more air flow in the attic the better and in theory that will pull up more air through the proper vents in the soffits. The ridge vents were added afterwards but the reason the gables stayed is my ridge vents will be covered with snow for weeks if not months in winter and contrary to popular belief they do not melt their way clear, thus when i need the ridge vents the most after a heavy snow fall to prevent ice damming they are covered with snow while the gable vents are fine.

The other thing to consider is that typically contractors put far too little soffit vent area in. A three inch continuous strip is a minimum. I see the perforated vinyl soffits and wonder how well they flow compared to a slot type soffit. Far worse are the drill in aluminum vents, better than nothing but not much.

One thing I do have on my up wind gable end vent is an interior tray hanging from the joists just inside the bottom of the vent lined with plastic and sized larger than the vent. I have fine screening in my vent but have found fine snow in the tray during unusual snow events. If not for the tray, the snow would sit on the insulation and eventually work its way down into the finished ceiling below. I have seen several older and couple of newer homes with mystery brown stains in the drywall caused by this. Unless they catch it when it happens the snow is long gone and melted by the time they get up in the attic.

 

[lml999]

<sigh>

As mentioned earlier, the roof is about five years old.

There is mesh in the ridge vent. I don't know if there's something over that, or whether shingles were installed right over the mesh. I do see some daylight when I look up in the attic, so there is some opening. I'm going to talk with a good local roofer to see what he recommends. Whatever it is, I'll have him do it.

There seems to be a couple of ways to create a ridge venting system, one is to lay that mesh over the opening and then simply nail shingles over it. Another way is to use a venting system that installs over the opening, and then shingles install over it. Seems like this second approach would give better air flow...but I also need to keep rain from blowing in...

 

[sportbikerider78]

I have forms like this that I installed when I did my roof. I have CRAZY blowing wind and lots of rain, with no drips below. I know because I am in my attic at least 3 times per year.
Could it be that yours are just not wide enough to cover the gap you have cut into the ridge? Maybe your roofer cut too much of a gap initially.

Show us a pic from your roof.