Thread: Mold in A/C plenum-Mold assesment or replace?

In a recent central Florida home inspection I found fungi (mold) in the plenum above the air handler. I haven't seen any yet because I'm new to the industry and was wondering how most of my fellow inspectors report this type of issue. Recommend replacing affected ductwork (since it can't be cleaned) without assessment or have a licensed mold assessor come in and do tape lifts/swabs for lab to verify fungi type and if it is active and then remediate? This is a retirement community so a do-it-yourself tape life or swab is not an option. Your thoughts would be greatly appreciated!

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Personally I don't recommend testing, all mould should be considered bad and the conditions which cause same rectified.

Unless that insulation can come off clean, that's a replace in my opinion.
Nasty!
I would also want further evaluation by a qualified HVAC contractor to determine why it happened, and what to do to prevent it in te future.

Of course you recommend replacing the plenum or damaged ductwork. Testing won't reveal much useful information. Get a HVAC tech in there to check it all out.

A few questions:

Is the mold only in the supply side, which is cool and dehumidified? Is the system oversized? (Poor humidity control)
Was the thermostat set to "On" instead of "Auto"?

How did you get that photo (looking up) above the AHU, yet inside the plenum? Is there an access panel or hole in the ductwork? That could explain the excessive moisture in the supply side.

What did the coil look like?

There's a great chance most of the flex duct has mold in it and will need replacement as well.

Thanks to all for your responses. Dom, more pics and answers to your questions:

1) Is it only on the supply side? Yes, from what I can tell. Didn't access the return register and no access to return at the AH
2) Is the system oversized? System is 3 tons which is about right for 1927 sq. ft.
3) Is the system set to "on" or "auto?" System was set to auto when I arrived.
4) How did you get the photo? Pic was taken by removing the maintenance cover in front of the evaporator coils and looking up into the duct. All seems were sealed so I don't believe warm garage air was getting in.
5) How did the coil look? Coil looked brand new for a six year old unit. Homeowner says she has the unit serviced routinely but not mention of a new coil.

Hope the pics help explain the location.

Client just sent me a couple of pictures of inside of his duct work, is concerned about "mold". I inspected the house in May of this year.

I believe pictures are from the main supply trunk in crawlspace, crawlspace was damp with some light visible fungus growth on framing, efflorescence/water stains on walls, some duct work leaks- all reported with pictures in Inspection Report.

What do you think, I never get to see the inside of duct work. I would appreciate any opinions.

He asked if I should have found this as part of the Inspection- but he didn't ask hard. Or, if the HVAC company should have found it, who he apparently had do duct repairs as a response to duct leakage problems I found.

The SOP specifically exclude mould. Also I don't know of any inspector which looks inside the trunk lines for mould.

What does your contract state? Does it exclude environmental issues, such as mould?

Since you found concerns and directed client to a HVAC tech, then I would put the onus on the HVAC tech.

Originally Posted by Raymond Wand

The SOP specifically exclude mould. Also I don't know of any inspector which looks inside the trunk lines for mould.

What does your contract state? Does it exclude environmental issues, such as mould?

Since you found concerns and directed client to a HVAC tech, then I would put the onus on the HVAC tech.

My Contract and our North Carolina SOP certainly do not include inspecting the inside of duct work.

I just got these pictures, and it occurred to me I didn't really know exactly what to think of them.

I want to respond intelligently to my Client, and was curious if anyone else had an opinion. For all I know, lots of duct board looks like this inside.

thanks, John p

Who was down in the crawl and why did they open the ductwork to take pictures?

It may be the photos, but it looks like dirt/dust to me. Any voids in the duct will allow dirt inside, since it's down below the house.

Dom.

I think I see dust and possibly some mould but can't tell with a washed-out pic. He should have the ducts cleaned. You did your job and he knew there were moisture issues and dirty duct issues.