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dman7800 04-13-2009 08:35 PM

Bad Attic Mold
 
I have a situation where my attic is becoming extremely moldy. We cannot put a finger on what is causing this problem. I am in the NW burbs of Chicago. There are many dynamics which seem to be causing this problem but nobody can put a finger on one of two things. I have been trying to reach Ed the Roofer via the link in his signature but I have not been getting a return call. I can post info but it is very complicated.

Thanks,
Dman

Ed the Roofer 04-13-2009 09:52 PM

I just sent you an e-mail.

My secretary had to take some time off for a medical issue and will be back tomorrow morning.

I am in the office tonight for another 1 to 1/1/2 hours if you see this message in time and wish to call.

Ed

dman7800 04-13-2009 10:08 PM

Thanks Ed, I got your email. I sent you one back. Look forward to hearing from you.

Dman7800

Michael Thomas 04-14-2009 12:27 PM

There many possible causes, but here in Chicago they usually come down to a source of warmer moist air from conditioned spaces below entering the attic and condensing onto colder surfaces, usually on the sheathing and rafters or trusses.

Assuming that the mold growth is not localized and clearly related to some specific moisture source (a kitchen or bathroom mechanical exhaust fan venting and the attic, a poorly sealed attic access hatch or pulldown stairway, an open chase communicating with conditioned space below, poorly sealed HVAC ducting - something of that sort), for example:

http://paragoninspects.com/images/mo...ehatch1500.jpg
Fig. 1

http://paragoninspects.com/images/mo...xhaust1500.jpg


then the problem is usually related to some combination of 1) multiple contributing sources of moisture in the attic (everything from continuous stud bays to the basement to poorly sealed recessed lighting fixtures in the ceiling below the attic), 2) insufficient insulation and vapor retarders between the condition space may attic, and 3) insufficient attic ventilation.

In a climate like Chicago's, the "typical" example (I observe this in around a quarter of the homes I inspect) takes the form of an attic with moisture damage and mold at the sheathing, most prominent the north side of the roof and closer the ridge, and the most common cause (assuming that this is a relatively recent condition) is that additional insulation has been added without taking care to preserve sufficient airflow from the soffits to the high vents at or near the ridge (the peak of the roof).

http://www.metrohome.us/resource_pag...in%20Attic.jpg

Other common causes include changes in venting intake and exhaust (for example recent re-roofing, and the ridge venting was nailed down too tightly, obstructing flow) and/or changes in occupancy and use. For example a client with three or four teenage children moves into a house previously occupied by a single, older owner - suddenly a lot more moisture from cooking, bathing and just human respiration is being introduced into the conditioned portion of the structure - or because the owners have recently installed a central humidification system and the supply ducts pass through the attic.

Deciding which of the three factors: moisture infiltration from conditioned spaces, insulation and vapor retarder's and attic ventilation (or which combination, and what proportion) is going to be the most effective (or the most cost-effective) to modify is a decision that has to be made on an individual basis for each property and occupancy.

And even then, there is a substantial element of trial and error - often you try the simple and least expensive solution first, even if you are not really confident that it will (completely) solve the problem.

For example if there are recessed lights in the ceiling below (a common pathway for conditioned air to to enter the attic, especially if they're located in a kitchen or bathroom) I look for evidence of increased discoloration at the sheathing above the lights, the same is true of other sorts of penetrations as well.

If I see this kind of localized discoloration in addition to the generalized discoloration on the north side it's possible that reducing air infiltration at these locations may be sufficient to substantially reduce condensation on the attic sheathing even if other problems (for example poor attic ventilation) are still present.

So it's possible that reducing air infiltration at this point will be sufficient to lower attic moisture levels to the point where condensation is no longer a major problem.

A roofer looking at the same attic may know from experience that improving the attic ventilation will also substantially reduce condensation, and if he or she recommended this solution they would not be "wrong", it just might not be the most cost-effective way to solve the problem (or, it might) - and unfortunately there is often no way to determine which solutions will "work" except by attempting them.

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Home Inspection: "A business with illogically high liability, slim profit margins and limited economies of scale. An incredibly diverse, multi-disciplined consulting service, delivered under difficult in-field circumstances, before a hostile audience in an impossibly short time frame, requiring the production of an extraordinarily detailed technical report, almost instantly, without benefit of research facilities or resources." - Alan Carson

dman7800 04-14-2009 09:04 PM

1 Attachment(s)
I talked to Ed and Im gonna send him some pics. The attic and roof is only 4-5 years old. Here is what I have going on.

Ed the Roofer 04-14-2009 09:34 PM

dman,

I don't recall from last nights conversation, but do you still have access to the inside of that attic, or did you seal off that scuttle hatch?

If access is available, I propose some moisture meter readings and possibly some FLIR IR photos to be taken.

I spoke with Michael and I believe that 2 sets of heads and eyes might be prudent in your case.

Has anyone in the family had any potential health issues since this first developed?

Ed

dman7800 04-14-2009 10:12 PM

Its on the second story and we use it for storage so it has a drop down staircase.

Ed the Roofer 04-24-2009 07:45 PM

What a rewarding experience this inspection wound up being for me, to have the talent and years of experience of Michael Thomas to jointly diagnose this particular home.

Although the attic was quite dark to film video in, the recording of the IR camera and the concurrent conversation that we had in the attic will definitely be of value at some point and time.

I guess what I am trying to say, is that when a home inspector is needed or a moisture mitigation diagnoses is mandated, make sure that the proper parties are involved.

Find people of a higher degree of talent and the final results will be quite valuable.

When I get the opportunity to upload the videos and photos, I will provide them for a review, in addition to each of our written reports.

The previous contractors advice and lack of building to the architectural specifications seem to be at the foot of all of these mold issue occurring.

If something does not sound right, or if it does not provide a complete solution, even if doen in a progression of viable steps, then go with your gut and reject that ill advised remedial work suggested.

Ed

Michael Thomas 04-25-2009 11:03 AM

Thanks for you kind words. It was great to have Ed and his crew there too, as he will be able to provide the client with suggestions and accurate estimates for corrective measures for the roofing and ventilation problems we discovered.

This was pretty much a classic attic mold inspection, and with the clients permission to reproduce our reports once this has made it's way though the courts (if that's in fact where it's headed) it would indeed be a good case study for understanding mositure and attic mold problems.

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Home Inspection: "A business with illogically high liability, slim profit margins and limited economies of scale. An incredibly diverse, multi-disciplined consulting service, delivered under difficult in-field circumstances, before a hostile audience in an impossibly short time frame, requiring the production of an extraordinarily detailed technical report, almost instantly, without benefit of research facilities or resources." - Alan Carson


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