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Posted

I need some referrals for Seattle area mold inspection companies. I will be reinspecting a house I inspected ten years ago. My clients had a new roof installed five years ago and started smelling mold three years ago. This year they observed moisture running down the interior sides of the exterior walls of the house. They called the roofer out who reported the plywood sheathing was not cut back when the ridge vent was installed and that was the cause of the mold smell. This small blunder is being repaired tomorrow and I am returning to the house on Friday to perform a full inspection.

The owner says the mold smell is so strong they keep windows open in the winter. These folks are real nice, but why they let this problem fester for so long is beyond me. If I find wet, moldy conditions in the attic I want to refer them to a reputable mold contractor.

Posted

Hi Brad,

Don't refer them to any inspectors who are calling themselves mold inspectors. Refer them to a real lab. NVL Labs on Aurora has a top-notch mold/asbestos tech there. He'll tell them what they need to do and if they need a full treatment supervised by the lab I'd recommend they contact Jim Renfroe at Wood Care Systems in Kirkland.

ONE TEAM - ONE FIGHT!!!

Mike

Posted
They called the roofer out who reported the plywood sheathing was not cut back when the ridge vent was installed and that was the cause of the mold smell.

I doubt it.

To get water running down the walls the water vapor pressure has got to be pretty high and that's got nothing to do with the attic. The lack of venting in the attic would most likely cause a problem in the attic and not on the interior walls of the home.

Are the rooms carpeted? What happens first is that the water vapor condenses out near the bottom plate of the wall, where there's lots of cold air. Carpet gets wet, back spots up with mold. Could have been going on for a while before things got worse and then they noticed water higher up on the wall.

Chris, Oregon

Posted
This small blunder is being repaired tomorrow and I am returning to the house on Friday to perform a full inspection.

I'm also having a problem imagining moisture running down the walls just from poor attic ventilation. Bad flashing, furnace now exhausting inside the home, blocked off bath/kitchen ducts? Any chance you can get there tomorrow before the roofer fixes his "small blunder" and maybe covers up the bigger ones?

Posted

Hi,

There's no opening at the ridge but there are openings under the eaves. I'll bet the insulation at the perimeter of the attic is touching the underside of the roof. Lots of houses around here they only have vents in every other rafter bay and the insulation is pushed right up against the roof in those bays without the vents. Moisture-laden air is moving up into the attic and insulation. When it hits the cold underside of the roof at the perimeter between the vents, it condenses and drips down through the insulation to the wall plate, saturates the drywall and then runs down the interior wall.

ONE TEAM - ONE FIGHT!!!

Mike

Posted

You need to get a good look at ALL the ventilation systems in that house. Make sure that the kitchen and bath exhausts are functioning (and being used), check the funace and water heater flues for leaks and or back drafts, and make sure that the roof vents are set up properly. If there is a crawl space it will also need proper ventilation or be conditioned space.

I had a wacky moisture issue in my home last winter that drove me crazy until I figured it out. All the window sash on the north side of the house had mold growing on the along the bottom rails. Turned out it was a loose flue on the water heater dumping moisture into the house. It was fortunate that a little condensation and mold were the only problems this caused.

Tom

Posted

Off to the house this morning. Thanks Mike, I have been referring NVL for many years. All interesting items to check into during the inspection. Having the owner of the house with me should help develope some better past history for the house.

Posted
Originally posted by Ponyboy

Off to the house this morning. Thanks Mike, I have been referring NVL for many years. All interesting items to check into during the inspection. Having the owner of the house with me should help develope some better past history for the house.

Well the mold issue was not as bad as the homeowner was telling me on the phone. The pictures below are of the the walls in the master bedroom. The white efflorescence looking stains look like water condensing on the interior wall surfaces. I did not find elevated moisture readings in the GWB. No black mold in the house. The attic was totally dry, well ventilated and no signs of mold or elevated moisture levels.

This house was a wreck when I looked at it five years ago. Since then; the windows have been updated, new oil furnace installed, new electric water heater, new roof, new gutters. The only structural moisture issues I found were a plugged dryer vent, the bathroom fan venting into the attic which was fixed by the roofer on Thursday, low air flow from the bathroom fan, and the main floor bathroom surround and floor rotting out and absorbing moisture.

These folks keep the furnace down at 40 degrees. They only turned it up when we went through a recent cold snap, to maybe 50 degrees and then turned it back down. I think when the interior temperature was raised the humidity level went up and then when they turned it back down the water condensed on the inside walls???

I convinced then to run their furnace more and heat the house at about 60 degrees. I will also have them repair the noted defects and improve the attic (low) and wall (probably zero) insulation.

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Posted

Hi Brad,

I agree, sounds like you nailed it. the walls of their house are acting like a cold coke bottle and all of that moisture they are creating is condensing at the coldest parts of those walls, the plates and corners. I often see the same thing in closed off sections of houses where elderly folks have been living alone for years. Hope you told them that the money they're saving by keeping the heat so low is probably going to cost them later in condensation issues.

ONE TEAM - ONE FIGHT!!!

Mike

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