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Attic Condensation


Ponyboy
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Afternoon inspection today has been vacant since April, heat off until the inspection today, built in 1999. Slab-on-grade daylight basement. No vapor barrier on the attic insulation.

Get into the attic and it is soaking wet. All of the OSB is moldy, wet and slightly swelled. Water is dripping everywhere and the insulation and trusses are wet with water dripping off of the sheathing. The eave vents were blocked with the cardboard insulation dams. In the garage the slab is spider cracking and water stains were present at all of the cracks. A few larger cracks clearly look like water coming in through the cracks.

The basement laundry room did smell musty and some mold was observed on the lower sheetrock which is against the foundation wall. The vinyl floor also had purple staining consistent with moisture damage.

Could slab moisture be making it through the house and condensing in the attic?

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My guess is that the origin of the moisture is, as you suspect, from inside the home, but the heavy condensation smacks of a severely under-ventilated attic.

These banks really make a huge mistake when they elect to stop conditioning the home.

Any potential humidity problem becomes all too real once the HVAC is unplugged.

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Hi Brad,

I agree with Michael, they should have continued to condition the air in the house. Built in 1999, it should have had an air change method present and they should have had it on. Houses are permeable boxes sitting on soil, which itself is a big water wick. When people live in them, they constantly open close windows and doors, add heat, remove heat and are constantly modifying the interior atmosphere of the house. When they leave, and some idiot at a bank makes the decision to try and cut their loses further by turning the heat off or waaaaay down, such as in the house I did yesterday, they just create problems that are going to increase the depth of their loss.

Here's an idea; the next time we have training seminars, let's provide some training for bankers that deals with how to close and maintain properties without increasing their losses. Bet there's a market for it.

What did you recommend?

ONE TEAM - ONE FIGHT!!!

Mike

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Huh, we have snow today? Where were you?

I agree with the Mikes but also think that the attic has been suffering since day one. That looks like more than the result of one season. Are your clients walking? I know I would. There's enough inventory out there that dealing with that mess (and the bank) makes no sense at all unless it is very, very cheap and they are willing to tear the place apart.

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That looks like more than the result of one season.

Agreed. If I had to swag how many air exchange fan timers I've found turned off, disconnected or with not tab settings, I'd have to say it's at least 65 to 70% of what I look at that's equipped with those systems.

People are their (and the house's) own worst enemy.

ONE TEAM - ONE FIGHT!!!

Mike

P.S.

Although there was that brand new house two winters ago. I was called in March. The couple were from Cali. They'd bought the house without getting it inspected the previous October - new house, they figured it would be perfect (Yeah, riiiggghhhht). The wife was getting headaches and nosebleeds; they suspected a problem because she had verified (by a doctor) allergies to common airborne fungi.

First, I found that though an intake duct and actuator were connected to the HVAC system in the basement, and the tabs on the timer up in the laundry room were correctly set and the switch was in the correct position, the system wasn't coming on. When I opened the attic hatch, the smell just rolled out into the house - it literally smelled like the inside of a cowbarn in winter. Up in the attic, the underside of the roof was covered with a fine mat of green fungi that is just about the same shade of green as the kelly green work shirts that I wear.

In the attic, the cardboard baffles had been collapsed and were blocking air from the eaves, ducts were disconnected from the roof and were venting interior bathroom air into the attic, there were too few jack vents and they'd installed gable end vents that were short circuiting the airflow up under the roof.

The house is located in a narrow draw with high hills on both sides and the gable end vents are oriented perpendicular to the draw and the prevailing winds so they were basically useless. Very tall trees surrounding the house keep it shaded all the time so the sun never reaches the roof to warm it up and initiate strong convection to dry out the deck.

It was the perfect storm of screw-ups. I recommended they get the whole house air change system fixed, tear off that rotting OSB deck, pull out and discard all of that insulation, treat all of the exposed framing with borates, re-roof, install full-length ridge vents, close the gable end vents and then reinsulate - making sure that the baffles weren't collapsed that time.

The client was a lawyer with one of the largest firms in the country. Since I haven't heard another peep out of anyone about that house in about two years, I'm assuming that the builder came back and bit the bullet hard on that one.

ONE TEAM - ONE FIGHT!!!

Mike

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This house was located North of Granite Falls. Icy snowy roads on the way out and worse on the way home.

The house had been owned by the same person since built. I don't think anybody been in the attic over the last ten years. This condition really looks like a long term problem. I will be recommending unblocking the eave vents and adding a fan to improve air movement in the attic. I am also going to recommend further investigation by a mold expert.

The roof sheathing was swelling from moisture, but I was not going to recommend removing it?

The moisture from the slab is the really intriguing part. The picture doesn't show the problem well. But every hairline crack in the slab looks like muddy water has seeped up and dried. A few cracks had clear evidence of active water seepage.

I am writing this report today so I was looking for other opinions.

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The roof sheathing was swelling from moisture, but I was not going to recommend removing it?

Geez, I would.

If you're dead set against saying "the sheathing should be replaced."

How about, "The sheathing is swollen and covered in mold. I'm betting that it'll need to be replaced to ensure structural stability and to reduce the area affected by mold. Re-decking then re-roofing then re-insulating the attic spaces along with any necessary mold remediation can easily add up to a very significant amount of money. Expect to pay 12-20 dollars a square foot. The affected areas are approximately xxx square feet. There may also be, and probably is, more damage that's yet to be discovered that could push those costs even higher."

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No furnace or humidifier in this house. The house is heated by electric wall heaters.

Chad, I am not against recommending a tear-off, just wanted to check with some folks before I made the call. I have not observed an attic this bad before. I will recommended roof and sheathing replacement, more ventilation and further investigation of the walls for moisture damage.

Great forum for talking about these issues.

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I wouldn't hestitate to write that the roof sheathing needs replacing.

Also, IMO, attic fans may not help much.

They've got to stop air leakage from the house in to the attic.

And then: I wouldn't recommend a "mold expert." It'd probably create more confusion than it would solve. After all, once the sheathing is replaced, the mold will be gone - notice it isn't infesting the truss wood. That's curious in and of itself. In fact, what's growing up there may not even be mold.

Camhoin Connell (sp?) would have some interesting things to say about this one. . .

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This is what it will look like when the roof gets replaced

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Yes some idgit lopped off the tops of the trusses, but man it was vented well; soffit and ridge vents, the original gable vents (the ridge for the new rafters was sitting on top of the drop gable trusses), and at least a half dozen exhaust louvres. I'm pretty sure they missed the moisture issue, because the new sheathing was all this lovely shade of blue-black.

Tom

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