Stained Roof Decking In Attic

[Nick Ostrowski]

I saw this at a townhome today in the attic. There was an inspection done on the house back in December and the realtor had a copy of the other inspection report. The other report made no mention of this and indicated the attic was inspected from the hatch opening only.

The attic had 10+ inches of blown insulation but there was no vapor retarder that I could see when I dug through the insulation. Can lack of a vapor barrier alone result in this condition with migrating moisture and staining on the decking? The house had continuous soffit vents front and back with insulation baffles in the truss bays and mesh ridge vent. The exhaust point of the bathroom vent fan exhaust ducts was not observable and there were no vent hoods on the exterior walls.

[Scott Patterson]

I saw this at a townhome today in the attic. There was an inspection done on the house back in December and the realtor had a copy of the other inspection report. The other report made no mention of this and indicated the attic was inspected from the hatch opening only.

The attic had 10+ inches of blown insulation but there was no vapor retarder that I could see when I dug through the insulation. Can lack of a vapor barrier alone result in this condition with migrating moisture and staining on the decking? The house had continuous soffit vents front and back with insulation baffles in the truss bays and mesh ridge vent. The exhaust point of the bathroom vent fan exhaust ducts was not observable and there were no vent hoods on the exterior walls.

Sure looks like moisture is getting dumped into that attic.

In the south we have blown-in and no vapor barrier, other than the paper on the drywall.

[Raymond Wand]

Lack of vapour barrier is likely not the cause if a oil based paint was used on ceilings below the paint can act as a vapour barrier.

Looks like you have warm air being pulled up from floor/wall juncture from rooms below.

Soffit vents likely clogged when the insulation was blown in.

[Nick Ostrowski]

This staining appears in the rear half of the attic only and it is facing to the North/North East so it is getting less sun exposure. How much of an influence does the orientation to the sun have on the formation of this staining? Is the area staying too cool to evaporate any accumulating moisture?

[neal lewis]

Looks like mold?

[wayne soper]

could have been moisture prior to insulation installation but nontheless, heat and /or moisture is/was leaking into the attic where it condenses at the cold area above the soffit vents, determining whether it is an active condition could only be determined by doing testing within the home that is beyond our SOP's
I would recommend further investigation to insure problem is not active.
And yes, that would be considered Mold by any Mold Mitigation company that comes in the future to test, so adding the presence of mold like substance in the report also is a must.

[Darren Miller]

Lack of vapour barrier is likely not the cause if a oil based paint was used on ceilings below the paint can act as a vapour barrier.


Who uses oil based paint these days or for the last twenty years??

[Raymond Wand]

If you Google vapour barrier paints you would not have to ask the question.

PREMIUM PLUS Interior/Exterior Oil-Based Primer & Sealer | Behr Paint (http://www.behr.com/dsm-ext/v/index.jsp?vgnextoid=75fa771eb42cb110VgnVCM1000006b 0910acRCRD#view=17;vgnextoid=75fa771eb42cb110VgnVC M1000006b0910acRCRD;channel=PROJECT_CENTER)

There are also latex based paints as well which could be used for the same purpose.

[John Kogel]

We can clearly see a baffle in every rafter bay, so it is not caused by a lack of soffit venting, even if a couple of them got crushed or filled.

Moisture is coming up from inside the unit, IMO.

Lack of a vapor barrier might not of itself be a culprit, BUT that means a poor air seal at wall intersections with the ceiling. Any indoor air getting into a wall cavity is going straight into the attic.

I think the worst condensation on the sheathing occurs at the coolest points - the lower areas of the north side. The moist air could be coming in from another part of the attic. Also, look for the standards - pot lights, bath fans and check the hatch cover.

I inspected a townhouse where the old couple were using one of those oil-filled electric radiator heater to heat the whole place. He said it was to save on heating bills. :D
The attic hatch was at the head of the stairway, so the hot air from downstairs had a straight shot up into the attic (stack effect). It was a mold farm up there.

[Rick Cantrell]

Once you have ruled out the most obvious and most likely conditions, then consider not as likely conditions.
WAG
Heavy foliage under eves
Moisture laden air from the foliage is pulled into attic through soffit vents,
then condenses on colder areas of decking.
This would likely be seasonal, and only under certain conditions.

[Egbert Jager]

A vapour barrier is more than a layer of low permeability material; All the penetrations through that layer have to be sealed. Vapour boxes, sealant or tape. And that's assuming the house was designed/framed and sealed by a diligent crew.

Its been said that the smoke coming from a hole the size of a pencil will kill a person in the next room before fire raises the termperature. A pencil sized hole at each pot light, smoke detector, ceiling fan, at all the elctrical penetrations through wall top plates adds up to fairly sizable flow of humid air. Throw in a bathroom fan, or a poorly sealed kitchen fan, the moisturee adds up in a hurry. Condense that moisture on a layer of water sensitive construction material that's backed by a non-breathable layer of shingles and you've created a fool-proof failure scenario. Hopefully you're not the guy walking on that section when it fails.

Worry about the all the big holes, then worry about how permeable your paint layer is.

[Mark Parlee]

The exhaust point of the bathroom vent fan exhaust ducts was not observable.

Nick
I have seen this many times. The vents were dumped into the soffits and convective air currents led to a situation like you are observing

[Matt Fellman]

Super common around here... always worst on the north/east sides. Often I'll find a wet crawl, signs of excessive cooking (boiling pots of soup, etc.) and/or bath fan routing problems. The insulation installers also cover the already minimal number of soffit vents in many cases.

As for a previous inspector not mentioning it, I've run into that too. It's not that they didn't see it... their defense is they aren't inspecting for mold. I've heard of a couple of cases in my area where that was the exact scenario. Seems ridiculous to me.... If I'm there an I see something odd I'm sure as hell going to mention it. I don't care how many attorneys have told me not to ever say the "M" word :)

[Lon Henderson]

Whenever I see that, it's always on the north facing roof side. Once, it seemed to be caused by the 20 large aquariums in the house that kept the humidity high in the house. The ventilation in the attic wasn't adequate for that much chronic humidity.

[Nick Ostrowski]

The reason I bring up the other inspector saying nothing about this is because he didn't actually enter the attic. His inspection of the attic per his report was conducted from the access opening only and he did not walk the attic. I have seen far too many defects in the far reaches of the attic to ever conduct the attic inspection from the access hatch alone. As long as it can be walked, I'm doing it. Not walking a walkable attic would be like inspecting the structural foundation walls and ceiling structure of the basement from the bottom of the stairs.

These pics are from my inspection this morning. The 1st pic is the view from the access opening for the attic. Looks OK. The 2nd pic is what I saw when I crawled in and looked at the far end of the attic.

[Bill Wieczorek]

Nick
I have seen this many times. The vents were dumped into the soffits and convective air currents led to a situation like you are observing

Agree with Mark. There was time when bath vents were ok when dumped into the eves and the county was ok with it. No longer the case.

About the oil base paint/primer, it can't be be sold in Illinois anymore.

[Rolland Pruner]

What about leaking chimney venting?? Is it close??

[Nick Ostrowski]

What about leaking chimney venting?? Is it close??

No chimneys in this house. Furnace and water heater were high efficiency models venting via PVC pipes to exterior at 1st floor level and the gas fireplace had a direct vent hood on the exterior wall.

[Greg Brainerd]

One thing that nobody has considered is ice dams. The damage is on only the north- northeast side. I'm in Montana, so I see a lot of that. I also see that from the bath fan exhaust dumped into the soffits, but that's typically when the exhausts are on the windward side and then the mold is fairly localized. Ice dam damage can be fairly localized as well. I looked at a house yesterday that had an east/west ridge and gable vents and a continuous ridge vent. An ice dam was forming only at the northeast corner- I know that because it was still there- and sure enough the roof deck was damaged right there with staining and delaminated plywood. Ice dams come back to ventilation- just a different source of where the moisture is coming from.

As for calling it out in the report, use the "M" word and use it loudly. Forgert the attorney's advice. They will profit if you waffle on this! In 2003, I described a similar situation as "unusual staining in the attic that should be investigated by an appropriate specialist". Turns out, the house had a mold history that nobody disclosed. The seller, agents and I were all sued. My attorney said I'd probably win in court, but it would cost more. That wound up at about $13,000.

I turned the claim into AIG promptly and they never responded. I called them the day before the response was due in court, and they told me to go fish- no mold coverage. They had done nothing but hang me out to dry, so if you're with AIG, change companies at the next opportunity- their policy isn't worth the paper it's written on. That said, I've never filed a claim with anybody else. They might all be bad, but if they aren't going to pay, I'd feel better being stiffed by a low cost carrier rather than by a high priced carrier.

[Nick Ostrowski]

I made liberal use of the word "mold" in the report and stated "possible mold/fungal growth". I do it any time I see this type of condition and I have yet to have anybody question me or come after me for stating something is mold or looked like mold. If somebody did, I'd bet them a mold test fee. If it's not identified as mold, I'll pay. If it is mold, you pay.

I've never understood the fear associated with calling something what it is.