Simple Strategies For Understanding &
Correcting Attic Mold
Attic mold is extremely common in
our Northern climate.
Attic Mold growth is generally directly attributable to 4 basic
1) Lack of adequate ventilation or improper ventilation
2) Existing, or past roof, or roof flashing leaks.
exhausted bathroom fans, and or, dryer vents.
damming as a result of inadequate insulation, and or,
to incorporate enough "Ice Shield Membrane along the eaves.
By far the most common cause of all attic mold is improper ventilation.
Attic Mold Pictures
attic mold photos are from some recent mold remediation jobs we
have performed during April and May of 2012. As you can see,
the mold types and severity vary from one attic to another. We
were able to restore all of these attic ceilings to mold-free
and clean looking wood.
discuss each problem and the appropriate remedy as well as
covering the basic mold remediation strategies recommended for
the Massachusetts area.
Let’s start by
explaining that in most attics the mold does NOT grow in
the summertime. This is because during the spring, summer
and early fall months the daytime temperature of the attic is
far to warm for the mold to effectively grow and the
humidity levels inside the attic are typically too low to allow
mold growth. Most mold will only grow between 40 and 90
degrees Fahrenheit. Some molds that belong to a special class of
mold ( the ones usually affecting northern climate attics)
called the Chrysophile molds will grow in temperatures as low as
the 20’s. Cladosporium is a black mold that we commonly
find growing on damp attic ceiling sheathing. Another common attic mold
is aspergillus. Its usually found growing in poorly ventilated
attics on the ceiling joists.
HOW THE MOLD GROWS
winter months when we heat our homes, some of the heat is
inevitably lost into the un-heated attic space. This hot
air mass then moves upward where it will dissipate outside if
the attic is properly vented.
If however the
attic is poorly vented the hot trapped air will encounter
the cold surface of the underside of the roofing boards or
sheathing. This hot –air- meets- cold-surface results in
dew-point being achieved. This dew-point created condensation
and is often more noticeable on the nails as the nails are more
efficient at conducting the cold temperature from outside. The
condensation then forms water droplets which can drip onto the
floor of the attic, or worse, sometimes run down
into the wall cavities below resulting in potentially “hidden “
mold which can be the source of frustrating to diagnose
Attic Ceiling Mold With Frosted Nail
Heads in the Winter
Often a roof
will have sufficient roof ventilation (ridge vent), but the soffits (eaves) are
not vented. Even more common is when a house receives new siding.
The siding contractor will install vented soffit panels. This
the eaves the appearance of being vented, when in reality they are
not, as no holes were ever cut into the plywood covering the
bottom of the eaves. Sometimes the attic is ventilated properly,
but an overzealous attempt to insulate has blocked the air flow
from the soffits to the ridge preventing proper ventilation. An
easy way to check whether or not the vents are there, or are
functioning properly, is to go up into the attic on a sunny day,
extinguish all lights and look for daylight coming
in along the edges. A well ventilated attic should allow visible
daylight in along the edges.
What is the best way to vent the roof?
ventilation is divided into two categories: Incoming air
and Outgoing air.
The most effective way for air to enter the roof is through
vents that are placed in the soffits along the eves. Continuous
strip vents provide the most reliable ports as well as
rectangular vents (if enough are installed). Round ventilator plugs are easy to install
but are usually to small to provide adequate air flow.
Stale or heated
air escapes through the top of the roof. There are many ways to
achieve sufficient ventilation including : Ridge Vents ,
Turbines or Powered Vents, Box Vents and Gable End Vents.
ridge vents are the preferred method for eliminating built up
hot air but may not be sufficient to ventilate short ridged
roofs like hip roofs.
heated attics or cathedral ceilings properly is often neglected
during initial construction. This often results in ceiling
drywall growing mold on the back side when the builder fails to
vent and baffle the area behind the ceiling insulation and
always need to be addressed by a professional roofer and special
attention needs to be paid to flashings around chimneys and
indeed any penetration found in the roof decking. Flashings
often require maintenance between roof shingling jobs and are
extremely important to maintain. Roof leak can often develop
into festering mold problems both in the attic cavity or worse,
inside of hidden wall cavities in the home.
occurs along the eves immediately above the plate-line of the
exterior walls. Leakage in this area easily penetrates into wall
cavities where it can become trapped between exterior finish
materials and interior vapor barriers. A surprisingly small
amount of water can raise the relative humidity of a wall cavity
to damaging levels. Mold growth may eventually become visible
along the wall base as it penetrates from exterior to interior
wall surfaces. More critically spore and VOCs (Volitile Organic
Compounds) released by mold can aggravate serious health
problems in the house's occupants. Especially at risk are the
very young and the old as well as allergy –sensitive or immuno-compromised
mild cases ventilation corrections are enough to cure the
problem in severe cases the roof shingles must be removed
and an ice dam membrane material (Grace is top rated) installed along the
lower eves to
prevent damming. It should run 6 feet up from the eaves.
On a very shallow pitch roof the ice dam membrane should
run the entire length from the eaves to the ridge vent. In severe cases
mold growth can spread into the exterior walls. The
drywall and wall insulation would then need to be
and disposed of and mold remediation performed.
vented bathroom fans:
Bathroom fans and dryer vents can generate a lot of moisture. They should
always be vented directly up and out through the roof. Often
times builders or do it yourselfers will discharge fans or dryer
discharges directly into the attic, greatly increasing the
overall humidity. Do-it-yourselfers often try to connect more
than one fan into a discharge and will commonly run the
discharge out to the eves or soffits rather than straight up and
out through the roof. The remedy is simple one fan one roof vent
directly vertically up through the roof overhead. On the outside
the vent has a hat and is not a risk for water leaks. Remember,
the soffit vents are air intakes. Venting a bathroom or dryer
through a soffit vent will allow some of the moist air to get
drawn right back into the attic.
Attic Mold Remediation Treatments
there are as many “treatments” for mold as there are remediators
out in the real world offering “mold remediation”. Mold spores
can grow at alarming rates. Under ideal conditions, one mold spore can develop into 12
million in twelve hours!
mold is feeding on the attic ceiling sheathing and ceiling
joists and what you can see with
the naked eye are millions and millions of them clumped
together. What you can’t see are the “roots”,
the mold organism
itself. The roots of mold (hyphae) can grow into the substrate
3/16 of an inch or deeper. What we think of as the mold (the clumped
spores) are actually the fruit or reproductive body, like an
apple on a apple tree. You cannot hope to solve a mold
problem leaving these roots and treating only the surface
of the wood.
Treating mold growth on a porous surface, such as wood, with bleach.
Bleach has an ion structure that prevents it from penetrating
into a porous substrate like wood, this means it leaves the
roots un-harmed. This technique leaves the
complete root structure intact and guarantees that if you ever
have a new water leak, or moisture continuing to condense on the
attic ceiling, the mold will go right into full
production and the mold problem will immediately return.
Our Mold Remediation System
Prepping the Home
surface mold growth
first thing we do is site preparation. We isolate the attic from
the rest of the house. We'll install an air scrubber machine. We put down protective
covering through the
walkways of the house leading to where we will be working. This
important step protects your home, and guarantees no staining or
dirt is carried into the carpets in the home. Your house is
important to us we will treat you as if we were working on our own house!
We apply a moldicide/cleaner/disinfectant/sanitizer
to the attic ceiling and joists that was specifically formulated
for mold remediation and will kill all types of attic mold.
Mold Stains - Getting Rid of the Evidence
This is absolutely a must. While mold stains are truly only
cosmetic in nature, failure to remove the stains will result in
untrained eyes (home inspectors )
mold is still active. Removing the stains is
the least important step scientifically, but it is the
Phase 4 -
Kill the Roots, This will keep it from coming right back!
Borate application to the Attic Sheathing and
We actually impregnate the attic ceiling wood with an
environmentally friendly solution from the mineral family.
This is made from an extremely finely ground mineral salt
specially designed for dissolving. It’s a cousin to the old
fashioned 20 mule team Borax we use in our laundry. This product is absolutely amazing. It's designed to
penetrate deep into the substrate (mold roots commonly grow 3/16's
of an inch into the wood) and kill the roots of the mold.
It not only prevents all hosts of decay and fungi, but it
also prevents wood boring insects such as; carpenter ants,
powder post beetles and termites.
Phase 5 - Application of an anti-microbial sealer
This is also sometimes referred to as an encapsulent sealer.
These coatings come either as a clear, or a white tinted sealer.
Many people mistakenly apply a white paint coating like Kills,
instead of a proper anti-microbial sealer. I've seen many
properties where the mold is re-growing right on the white paint
coating. A high quality anti-microbial sealer should also be applied if
there is any chance of the ventilation corrections not being
adequate to properly vent the home's moisture out of the attic,
or if, the home has higher than normal basement or upstairs
Note: It doesn't matter if
ventilation corrections are done before, or soon after mold
remediation is completed. But, ventilation corrections
must be done before the cold
weather returns. In Massachusetts that means in October, before
Long Extended Warranties
Advanced Mold Remediation warranties average from 7 to 10 years.
How long does it take?
Typically we can complete an
attic project in 1-2 days...Two days if we're applying a sealer. The work for an attic is typically
done by a three man crew, who work exclusively on attic and
crawlspace mold problems day in and day out, week in and week out.
They are highly trained and very efficient.
How Much Does it Cost ?????
that are currently being charged by other companies can vary
significantly. Average attic remediation costs industry wide
vary from 2500 to 6000. Our rates average between $2000 - $3900
with a 10 year warranty.
always contractors who will tell homeowners that their entire
roof needs replacement after going through an extensive
remediation and routinely charge tens of thousands of dollars
for projects that could be handled for a few.
companies want to tell you to replace your entire roof (boards
and all), and these estimates often range anywhere from 10 grand
to 30 grand, and routinely don't even solve the problem. Here's
why: What happens is a roofing company advertises mold removal,
not understanding all the causes of mold removal, nor some of
the solutions available today to remediate mold without removing
the attic ceiling sheathing. They see mold as a good way to land a big job to unsuspecting
homeowners, and don't realize that nearly always the mold is
caused by ventilation problems inside the attic and not on the
roof. Even though any good roofer should understand an attic
should have proper intake (soffit) vents, and proper exhaust
vents (ridge or box). They tell the homeowner they should
replace an entire roof and then often will re-install improper
ventilation or won't correct things like a bathroom ceiling vent
improperly venting into the attic.
process is far more effective and contains more steps than
our competitors. We offer long extended
warrantees to protect both your home and your wallet.
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