PEELING, FLAKING EXTERIOR PAINT & MOSS OR ALGAE ON
SURFACES
Depending on what part of the country you're in this homeowner problem
will take on different meanings. In wet, temperate climates there is more
trouble with moss and mildew and painting or staining are made all the
more difficult because of the dampness. In dry climates like the Prairies
the peeling and flaking are often a result of sun and wind damage. For hot
extremely dry climates the peeling and flaking are due to the sun as well,
but also the heat. The most common thread that runs through each and
every one of these scenarios is the product used and its application.
This topic actually encompasses two distinctly different issues, one deals
with environmental affects on outdoor surfaces, the arrival of moss for
example, while the other is the application of new paints and stains and
how best to maintain them.
Cleaning Exterior Surfaces of Moss & Algae
This won't be as big an issue in some parts of the continent but it is a
problem for many homeowners. North facing walls and roofs, pathways
and steps can all fall victim to the slippery and unsightly green stuff that
shows up when things are wet and warm. There is virtually no way other
than cleaning to avoid this problem for walls and flat surfaces on the
ground, but roofs can be treated a bit differently. There are a multitude of
cleaning products on the market and you will have to make yourself aware
of what's available in your community, but, here is a bit of an overview of
what can be used:
1. Bleach-based products work well for moss and algae on walls, paths
and steps. There are very strong solutions, like one called 30 Seconds,
that kill the spores once the bulk of the moss is gone. Any spores that
are left behind will develop into new moss very quickly.
2. Caustic cleaners (virtually the opposite to bleach and not to be mixed
with it) are good for cleaning algae from steps and other surfaces like
walls. It doesn't necessarily kill the spores but does clean away the
slime and grime. One such product is called The Duke, a Ducasolbased cleaner that can be used straight or diluted for a variety of jobs.
3. There are other products on the market that are iron-based, iron is
effective in killing moss, but you must use extreme caution for a variety
of reasons. Moss killer for lawns, either in granular or liquid form, can
be harmful to anyone with any kind of respiratory condition like asthma.
It can also stain sidewalks and other surfaces like siding and gutters if
it's used incorrectly or carelessly. There are strong roof moss killers
that are iron-based but these should not be used for the reasons
mentioned.
4. Elbow grease always works too, although it isn't as effective in keeping
the moss at bay for very long.
Prevention is always a good thing to teach your customers. If there are
places around their property where moss and algae are constant problems
and even dangerous, there are things that a homeowner can do:
1. Open up the space to more airflow. Airflow, sunlight and dryness are
all enemies of moss and algae. They like it dark and damp with nice
still air. Tree and shrub trimming can be done, as well as examining
the way fences and other obstructions work near the house. Perhaps
removing a solid fence and either leaving it open or adding an open,
chain link fence would work. Re-locating a shed that may restrict
airflow is a good idea too. Cutting back trees and shrubs is critical to
the health of a house and should be a part of an annual maintenance
schedule.
2. Change path surfaces from solid and potentially slippery to coarse and
porous.
3. Install some sort of anti-slip strips on stairs even asphalt shingles if
need be, to reduce the falling hazard. This is very important for seniors
or anyone who is a bit unsteady on their feet. There are stainless steel
grids available on the market too (getagripstairtreads.com).
4. For roofs, sloped or flat, the homeowner should use zinc-based
products that come either as rolls of striping or tubs of granules. The
zinc leaches across the roof as it rains and creates an environment
that is unfriendly to the moss and algae. This should be replaced every
couple of years regardless of what it says on the product.
5. Keep things clean and dry as much as possible. This means removing
leaves and other debris as they occur and keeping things tidy and
unobstructed.
Peeling & Flaking Paint
Once any moss or algae has been removed from exterior walls the
homeowner may then have to tackle loose paint or stain. There are a
variety of reasons why this happens but the most common one is poor
preparation before application. Paint and stain can become 0old and fail
over time, but this usually results in fading and thinning, not actual peeling
of pieces of product.
Here are some common mistakes made when getting ready to coat an
outside surface:
1. Coating damp or even wet material. The surface may seem dry
enough but if the weather has been wet, or if the wood is newly
installed, the moisture content may still be too high. This is particularly
critical for any oil-based product. Oil paints and stains, unlike latex or
acrylic products, cannot "breathe" and form a solid membrane that
traps moisture. Once the sun comes around and hits the wood surface
the trapped water tries to escape thus causing bubbles.
2. Coating over existing paints or stains and not knowing what they are.
There is a standards rule about placing latex products over oil but they
needn't always mean failure. Preparation is crucial in this case too.
When the homeowner doesn't know what was there they can still
scrape, wash with a TSP solution (trisodium phosphate), and sand.
Once the surface is clean and dry the homeowner would apply a top
quality exterior wood primer to establish a good base before final
painting.
3. A common error made often is painting or staining when it's too hot, or
when the sun is directly on the surface. When any coating dries too
quickly the surface hardens and the under layer stays soft. The product
doesn't have a chance to cure properly and eventually fails. Care must
be taken when applying any exterior coating in the summer.
4. Using the right tools is also important such as the right type of brush
and roller. It doesn't pay to use cheap tools the result will tell the story.
5. Finally the homeowner should always use the right product for the job
at hand. There can be a lot of difference between coatings and many,
even expensive ones, will not be applicable for every surface or use.
The homeowner should take care to give the right information at the
store in order to get the right product.
Peeling and flaking of old paint and stain can be dealt with as long as a
step-by-step approach is used. Council your customers to take their time,
do their homework first, and call in the experts when there's any doubt.
Copyright Morgan Jensen 2010