Exterior Peeling Paint, Paint Blistering & Cedar
Bleed
The Problem: Paint Failure
A major problem facing painting contractors and homeowners, alike, is paint failure and/or cedar bleed (tannin) caused by unwanted moisture buildup. The problem is common to houses of all types and ages, but it is most prevalent on houses with wood shingles or clapboard siding.
There are 3 major symptoms of paint failure due to trapped moisture buildup:
can range in size from inches to feet and may actually have water held in them (see photos)
Cedar bleed (tannin) , a rust
colored surface discoloration, appears in and near soft and split wood
grain as well as nail heads and butt joints, since moisture will always follow the path of least
resistance.
Rusty nail heads occur when
moisture, following the easiest route out, flows past the steel nail
causing rust to form around the head.
These are some of the typical paint failures that we are encountering in Southern Maine . . .
The Cause: Trapped Moisture
So...there's water, water everywhere, but where is it coming
from?
To understand why your or your customer's homes
experience paint failure, see how the following elements contribute to the
problem:
What is your temperature?
Due to the temperature differential between a home's interior and
exterior, a sweating process occurs and causes condensation to develop in
between the partitions. The best example of the process is to look at a
window without a storm window on a cold day. Moisture condenses on the
inside of the windowpane and you can write your name on the foggy glass.
It is the contrast between low exterior and cozy 68-70°F interior
temperatures that causes the vapor to condense on the inside of the cold
glass.
How is your home heated?
Most homes that experience paint failure and/or cedar bleed due to
trapped moisture release are heated by forced hot water systems. Homes
with hot air and electric heat systems also encounter the problem, but it
is usually not as severe. In general, the forced hot-water heating pipes
are commonly positioned at the base of the interior surface walls on each
floor of a dwelling. The water in those pipes is normally heated to 180°F.
The temperature differential between the inner wall and the exterior
substrate on a cold night can be as much as 160-180°F - a condition
lasting throughout a six-month heating season. During that time, heated
air condenses into water vapor inside wall cavities. You can readily see
what happens to the interior window surfaces with a 68-70°F temperature
differential, so you can imagine what happens between wall partitions with
a 160-180°F differential!
Peeling limited to the area outside your bathroom?
If so then chances are that moisture from the bath and shower (primarily)
is working its way through the wall and causing the paint on the outside of your house to peel. Baths and showers
generate a lot of humidity, and some of that water vapor is probably working
its way through the drywall, insulation, sheathing and even the building paper.
From there it continues into the wood siding, and it's just a matter of time
until the paint falls off.
Correct this problem right away, not only so the paint will stick, but because
the moisture may cause mold to grow inside your walls, especially in colder
climates.
The first step is to reduce the humidity in the bathroom. Weather permitting,
open a window while you're showering or bathing. If you've got a bathroom vent
fan, be sure to use it and make sure it's actually working. Let it run for at
least 15 to 30 minutes after you're done bathing or showering.
Your bathroom vent fan may be underpowered or improperly installed. Modern, higher quality vent
fans are relatively inexpensive for the results they provide. These fans can have a much higher
CFM (cubic feet per minute) while being quieter than the inexpense one that the builder may have stuck you with.
Click HERE to calculate the minimum CFM you need for your bathroom.
The second step is to stop the water vapor from moving into the wall. In
moderate and cold climates, you normally install a sheet of plastic as a vapor
barrier behind the drywall. In your case, it's probably missing. Instead of
tearing out the drywall to install one, simply let Maine Painting repaint your
wall with a primer that's designed to act as a vapor barrier. Then we apply two
coats of paint specifically formulated for bathrooms. Once we have that taken
care of, we can address the peeling paint on the exterior.
Spring cleaning anyone?
After a long cold winter, spring arrives and you open the house to air
it out. Right? WRONG! All of the moisture trapped
behind the substrate wants to escape. The sun hits the side of the building and acts
like a clothes dryer (without the tumble dry option), drawing the moisture
out through the siding. The surface temperature of siding exposed to the
sun for an hour or more in the summer can reach 140°F. If the moisture
cannot get through the pores of the paint, it will build up such pressure
that a blister will form on a painted surface, or the paint will peel,
and/or cedar bleed will occur on a stained surface.
Shade vs. SunMoisture
problems are most common on the surface areas that are interior-heated and
receive a large amount of sunshine. Areas shaded by shutters, blinds,
eaves or overhangs will usually show little if any paint failure or cedar
bleed, since the absence of extreme heat differentials minimizes the
moisture accumulation and drawing effect. As a result, the side of the
house that rarely receives direct sunlight will commonly show less
paint/stain failure due to unwanted moisture release.
The Cure:
If your home looks like any of the images above, then you need us!
In my many years of painting homes in Southern Maine, I have yet to find a painter that
knows how to permanently solve these problems. They will simply scrape, spot prime and
repaint only for the problem to return again the following spring.
Maine Painting LLC uses several
proven methods to permanently solve the problem. Depending upon many variables we may
use or recommend one or several of them. We also have a proven a moisture release system
that prevents and cures paint failure and cedar bleed problems on shingles and clapboard
siding (also called lap siding). Our process is so effective that it is backed up by our
written guarantee: The paint or stain on your home will never peel or blister again due
to this cyclical moisture problem.
Call or Email Stan at Maine Painting today for a free, no obligation estimate and appraisal.
WedgeVent Wedge Vent
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