Hello everyone. I have some major moisture issues in my attic. I'll try to be as thorough as possible. Sorry in advance for the long read.

We had a new roof put on in October 2011. I live in Colorado. That winter, there was zero issues: interior water damage, exterior siding damage, attic moisture, etc. Within the last 3 weeks or so we've had two snowstorms come through that dumped about 4 inches each time. With in the last 3 weeks, temperatures have not peaked over 40 degrees and got as cold as single digits. A little over a week ago I noticed what appeared to be water marks on the outside of our masonite siding, mainly on the back of the house first. As the days progressed and the snow on the roof began to thaw I noticed these water marks get worse and buckling begin. The water marks also began to appear on 3 out of the 4 sides the house

I went into the attic to check for any type of damage as I automatically assumed it was a roof issue. Below are some pics I took. It appears the plywood and rafters are total soaked. However, I did not see any actual dripping or streams of water. The attic moisture was isolated only on the back of the house. We have 3 soffit vents each on both sides of the house and 3 ridge vents. None of the vents are blocked.

Here is where I'm baffled. No variables have changed except for the new roof being put on. Thermostat has remained constant compared to past years, humidifier has stayed constant. There is no sign of any interior damaged, it all appears to be exterior. The house is 12 years old with zero moisture issues before. I'm not sure how this all would have happened within the last two weeks. Another thing I find odd is that my neighbor behind my house just had a new roof put on in the last month as well as had the house painted. I've noticed that they to now have these watermarks appearing at the bottom of the eave of their house. They had no previous water markings on their siding until after their roof was put on.

Any help would be appreciated. Do I need to look at better insulating options? Is this possibly a roof issue? Is this a project that is going to come out of my wallet or can I go back to the roofing company or file a claim with my homeowners insurance. Thanks again for the long read.







Roof plywood on the back side of the attic

 

Looks like ice dams to me, but have you looked for ice on the roof? Back of the house faces which direction? I'm assuming it's the side that would get afternoon sunshine?

The only thing you might have on the roofer is if you have a code in your area that requires ice and water shield on the first 3' or first 6', and along rake (gable ends), and the roofer didn't do it. Or if they omitted roofing underlayment (as some contractors do) when that is required either by local code or by the shingle mfg's warranty. Roofers can't help it when they do their job correctly and ice causes water to backup and run uphill.

But it would probably be helpful if you would identify in the attic exactly where the sheathing or insultion begins to get wet... is it at the seam above the first sheet of plywood from the gutter or the first 2 sheets, or the first 3 sheets, or what? If it's an ice dam, it usually will be on the lower 1/3 of the roof.

I would contact your insurance adjuster asap.

 

There may be several things going on here from weather to ventilation, to did they cover the ridge gaps. Let's review a couple and start trimming the list down.

1. It happens all too often, a new roof and the installers covered the gaps at the ridge and forgot to cut them out before the ridge vent was installed. Inspect and test from the inside to be sure air is flow out those ridge vents.

2. You said <We have 3 soffit vents each on both sides of the house and 3 ridge vents.>
In general, soffit vents should be the full length of all soffits and the same for the ridge vent. What size are the soffit vents and what is the total length of the ridge venting. Plus, what is the approximate floor area of your attic.

3. In your last picture I don't see baffles to hold the insulation away from the bottom of the roof and provide a gap for air flow. There should also be something at the end of those rafter bays to keep the insulation from filling the soffits.

4. With that much moisture, it is probably a combination of too little venting and too much air leakage into the attic. Insulation prevents heat flow, but air leaks carry the moisture. Have you done any air sealing?

5. Do you have any heat ducts, supply or return in the attic?

6. Are your bath and kitchen fans vented to the outside, and where? Also, where does the dryer vent exit?

7. What is the humidity level inside your home? Do you run a humidifier or dry cloths inside. Stacking firewood inside will add a lot of moisture.

8. Do you operate any unvented gas heaters?

These will get us started.

Bud

 

1) Just like the ridge, the soffit vents need to be as continuous as practicable. Lack of uniform air ventilation from eave to ridge will create areas of non air movement. Like the ridge, its best to make the soffits 100% vented.
2) Be sure to install vent baffles. The loose insulation fill can easily block air movement.
3) Don't thin out the insulation at the eaves. Low R's at the perimeter walls will increase the chances of ice daming. In your next home, specify roof trusses with a 12" 'raised heel' so you get at least a full 12" insulation depth above the exterior perimeter walls.
4) Was ice/water shielding installed on the roof at the eaves, rakes and valleys? At the eaves were they installed 24" (horizontal depth) inside the vertical plane of the perimeter wall? In your case that probably means at least 2 rows of ice/water shield. The best stuff on the market is the Grace product. Most contractors hate it because of its unforgiving adhesive properties if you misalign the product but it selfseals the best at nail penetrations. Ideally too, the ice / water material should have been extended down the fasica before the fascia cover, drip edge and gutters were installed. Any ice buildup in the gutters will protect the fascia board from premature rot.
5) Any penetrations in the ceiling gypsum board ceiling? Any recessed lights? Avoid recessed lighting in an attic situation. Limit recessed lights to ceilings with conditioned spaces above. Even with attic insulation, any penetration of the gypsum board is an avenue for warm moist air to enter the attic. Even a junction box for a surface mounted ceiling light fixture is an avenue for warm moist air to leak into the attic. Seal the penetration with spray foam from the attic side.

Finally, test your interior space humidity.

 

Sorry for the delay on a response. Been traveling for work. I went back up to the attic and the roof to look around again after most of the snow had melted. There is no damage on 3 out of the 4 sides of the house. Both a roofing adjuster and a insurance adjuster have came out but can't determine the issue. Our insurance company is now sending a engineer out. When I was back up in the after I noticed that neither the soffit or ridge vents are obstructed and air is flowing through both. Below are some pics I snapped while I was on the roof. I still don't see any sign of moisture in the attic except on the back of the house even though water damage is showing on 3 sides

New vents that were installed when the roof were put on.



Edge of the smaller roof..



Top of smaller roof.

 

Let's see what the engineer says, but the problem is obvious. Adding humidity to the inside that is getting into the attic and probably through the walls and reaching a cold surface. Why now and not before the roof will take some more investigating, but what you are seeing on the walls is probably not coming through the shingles.

What is your inside relative humidity and temperature?

Bud

 

We keep the house around 72 during the winter and the furnace humidifer is set at 28%. This around where its always been during each winter.

 

Are you saying that those turtle vents were added when the new roof was put on? If you had, and still have, continuous soffit and ridge vents, then those added vents could be one source of the problems you're seeing now.

Any vents between soffit intakes and ridge outlets can interrupt and/or disrupt the function of the soffit-to-ridge system. I will look for some references on that but, as a first trial, you might try blocking those from underneath. Did the roofer consult with you before installing those? If so, what reason did they give for adding them?

 

In the 4th picture down, it looks like you are missing several ridge cap shingles. (at least 3)

None of the pictures show any continuous ridge ventilation.

 

Sorry. I should have clarified. They replaced all existing vents. No additional ones were added.

 

I'll get a closer picture of the ridge cap shingles. I'm not sure how many should be there. Complete novice here.

 

Thanks again for everyone's responses. I'm really surprised that there is no sign of water damage on the interior. I've checked the sheet rock in all places of the house. With as much damage to the exterior I would have thought water would have found a way inside. I'm going to knock on my neighbors door behind me tomorrow as I'm starting to see the same moisture signs on their siding and they just put a new roof on and painted the exterior with in the last month and a half. I don't think they've noticed it yet.

 

So here was another question I had that I don't believe I asked before. Regarding ventilation in the attic. Would installing additional soffit vents on the back side of the house cause problems? Like I mentioned before, there are 3 already on both sides of the house, but is adding more a issue? I'm going to look into warm escaping into the attic, but would having more vents up there help with keeping the temperature down in the attic?