House attic mold is one of the most "popular" items in my property inspection reports. And now is time for an explanation of how to kill mold and/or how to clean mold in the attic. But before I do that, let me give you a little advice, something to consider before you sign a few (if you're lucky) thousand dollars contract agreement with a mold remediation company. mold remediation services are often beneficial
Attic mold remediation TIP - an alternative (to consider):
Let us assume that you are in the middle of a real estate transaction, and the home inspector just revealed to you that your entire house attic is contaminated with mold.
If you have a brand new roof, you can only blame yourself or try to blame the roofing contractor for not checking the attic before replacing the roof (he will laugh at you unless you've actually asked the guy to check the attic before the roof replacement). If you have an older roof, the importance of this advice is even greater.
Call at least 2-3 mold remediation companies for an estimate - specify to the representatives that you want to have the mold removed and the attic ventilation system corrected/installed if necessary / ask if the attic insulation requires replacement.
With the numbers from the mold remediation contractors, call 2-3 roofing contractors, and ask them for a quote on the roof replacement cost, including decking boards/plywood (ask the roofer to check the attic area), attic ventilation improvement, and insulation if necessary.
Be cautious if they only suggest humidistat controlled power vent installation - without properly functioning soffit vents or any type of vents along the lower portion of the roof, this might not be an adequate solution.
If the attic insulation replacement is not required (in most cases, it will not be possible to tell without laboratory testing), ensure it's sealed with plastic foil before the roof and its decking replacement. Fold the foil sealing its contents after the contaminated decking has been removed, and dispose of it as a regular waste and asbestos testing kit are available at cheap rates.
If you only have a small area of attic contaminated with mold, the roof replacement option would be more expensive. But with an entire attic that needs mold remediation, it might be cheaper (or even much cheaper) to remove all contaminated decking, install a completely new roof, and correct ventilation issues.
I have seen $3,000.00 - $10,000.00 invoices for the attic mold remediation process in approximately 1000 square feet of attic area.
Benefits of the roof/decking replacement over the mold removal:
roof and decking replacement might be cheaper than cleaning an entire attic contaminated with mold
the real-estate transaction killing mold is gone
attic ventilation improvement is much easier during the roof replacement and often handled with no significant/additional cost
the buyer gets a brand new roof
Even if the roof replacement price is slightly higher than the mold remediation process, it is still worth considering because you are gaining a valuable house update (new roof) that will be disclosed on a real-estate listing.
In some cases, the roof decking and framing are contaminated, and replacement of the decking only would not entirely solve the problem. In such a case, you'd have to clean contaminated joist or trusses.
How to kill mold and how to clean mold in the attic.
This is not a mold killing or mold cleaning case study. It is just an explanation based on my observations and EPA (Environmental Protection Agency) recommendations.
Even if you are dealing with a small contaminated attic area - 10' x 10' is the maximum area recommended by the EPA to be treated by non-professionals, forget about killing mold by spraying it with bleach or other disinfectants. It's been confirmed by laboratory testing that it does not kill all of the spores and in most cases, you'll be just making a mess.
The best way to kill the attic mold (just like any other mold) is to remove it from the surface it's growing on or remove the contaminated surface!
EPA recommends four mold cleanup methods, and all of them can be applied in the attic, assuming that it is a small area (up to 10 sq. feet).
You can clean the surface by using a wet vacuum - the type you can fill its tank partially with water to contain mold residue from the contaminated surface.
Wipe the surface with a damp sponge or rag - use clean water or wood cleaner.
Use a high-efficiency HEPA vacuum cleaner on thoroughly dried surfaces, and dispose of the picked-up contents in well-sealed plastic bags.
Remove all contaminated material, seal it in plastic and dispose of it as regular waste. They recommend using a HEPA vacuum after this, but in the attic, you'd most likely have to remove the floor insulation (if contaminated). You can also cover the insulation with plastic foil and fold the foil sealing its contents after the cleaning process.
You may or may not have any allergic reactions to mold. However, always use protective equipment, especially in the attic area exposed to insulation fibers and dust.
As minimum protection during the mold removing procedure, EPA recommends Gloves, an N-95 respirator, and eye protection (preferably fully enclosed goggles). You can add a half-face respirator or full-face respirator with HEPA filter, disposable full-body clothing, headgear, and foot coverings as additional protection. Read more about professional mold removal