On This Page:
Peeling or Rotted Hardboard
Paint Peeling from Masonry
Hiring the Best Contractor
Did you know that if a coat of paint is too thick it could be
There is a limit to the number of coats of paint that a surface can
support. As the paint thickness builds up over time and
the coatings get older, they loose their flexibility. As
the substrate expands and contracts because of
temperature fluctuations or moisture, the paint film may no
longer be flexible enough to move with the surface. At
this point, cracking or flaking of the coating usually results.
Too thick a layer of paint can also seal the surface causing the
paint to blister, see blistering below.
It is not uncommon to put a coat of paint on a surface that
appears sound only to have many layers of paint peel away.
Then the surface must be stripped. (When this happens,
more than one layer of paint will peel. If only the last
layer of paint peels, then there is a bonding issue. Most
likely, the surface was not properly prepared prior to the most
recent coat of paint.) The ideal thickness of a new coat
of paint is about 4mm.
Why does hardboard siding peel and/or rot?
Hardboard siding is
reconstituted natural wood. It is
fabricated by reducing natural wood to fibers, adding resins,
and then pressing the fibers together into panels. It can
be either tempered or standard. Tempered board is denser
and has a higher moisture resistance. Standard
hardboard should not be used outdoors in areas where it will
be directly exposed to the weather. Peeling is often due
to poor maintenance of the coated surface. It generally
originates at butt joints and drip edges. Water contact
directly with bare hardboard
in these areas eventually penetrates into the board, which
permeates and expands the compressed wood fibers in the board.
This leads to the board
rotting. The swelling process is irreversible,
resulting in delaminating of both the paint film and the board.
Hardboard must be primed, if it was not
primed by the manufacturer. All joints or bare edges must be
primed and caulked to avoid contact with water.
OSI Quad sealant is an ideal caulking to use on
hardboard siding. (OSI
Quad sealant is used exclusively by Scott's Painting & Staining Inc.
when any type of siding replacement is performed.) Coated
hardboard surfaces require regular
maintenance to detect possible areas of deterioration or cracking before
board failure occurs on a large scale. Where cracking or peeling
is observed, it MUST be scraped and sanded
immediately, then primed, caulked if necessary, and top coated.
All loose paint must be removed, and the edges of the areas of good
paint should be sanded smooth. For more information about rotted
hardboard siding replacement and getting money back from the
manufacturer for damaged siding check
out our rotted siding page.
Why does the paint keep peeling off of my masonry (concrete
blocks) and/or brick? A common
cause of peeling paint on surfaces composed of mortar, brick,
concrete, or concrete block is
efflorescence, where soluble salts are present. When
dissolved by water, they are carried to the surface and remain
after the water has evaporated. These salts can push paint
away from the surface and peeling results. You may also
notice white raised lines on the blocks; these are the salts
surfacing. Efflorescence occurs on brick walls of new
construction. A common building practice is to treat new
brick or concrete with muriatic acid, rinsing with water to
clean away excess mortar. Rinsing removes only those salts
on or near the surface. After painting, salts remaining
within the bricks will absorb the moisture and travel to the
surface, causing peeling. Peeling can also occur when
alkyd or oil paint is applied over unetched concrete.
Alkyd resins that come in contact with an alkaline surface form
a soap film between the concrete surface and the coating, called
saponification. This will cause softness and loss of
adhesion of the alkyd coating.
If efflorescence is evident, it must be removed before repainting.
First, remove all flaking or chalking paint from the damaged area by
wire brush and power washing. Fill cracks with masonry patching
compound, latex concrete patch, or a caulking compound such as
Vulkem 116. If the surface is very porous, apply an
alkali-resistant primer or block filler, such as
Sherwin Williams Loxon Masonry Primer. Cover with a latex
paint such as Sherwin Williams SuperPaint
Duration. To prevent
recurrence of efflorescence on interior walls, the exterior walls should
be sealed. NOTE: Extraneous water sources must be removed
before painting (e.g. migration at ground level, often caused by poor
Why does my (lap) siding keep blistering?
Blistering refers to the formation of a blister caused
by vapor expanding between the coated surface and the paint
film. Due to humidity, construction defects, or
lack of effective vapor barriers, moisture condenses on or
saturates wood siding. Lower humidity and high temperature
generate pressures within wood and on adhesive bond of the
coating as trapped moisture evaporates. Solvent-based
coatings (oil-based products) are most susceptible. Fresh
blisters are filled with water. As the surface dries,
water evaporates, but the paint film does not recover.
Blistering is accelerated by the swelling effect of moisture on
wood. Continued swelling and contraction between day and
night humidity and temperature variations weakens adhesion.
If blistering was caused by moisture, a number of solutions
exist. Repair loose caulking and install vents or exhaust
fans. If the home has lap siding, install siding vents.
Vents or fans allow moisture from in the house to evaporate
before penetrating wood siding. This will minimize future
blistering problems. If you have lap siding, painting
wedges can be driven between the layers of lap siding.
This allows a ventilation-gap for moisture to escape. This
solution solves problems where many layers of paint have
completely sealed the bottom edges of the lap siding to the
following piece of siding. Scott's Painting & Staining
Inc. can install these wedges prior to painting, if so desired.
Sand and scrape peeling paint to bare wood. Prime exposed
areas and repaint. If large areas of paint have blistered
and need to be removed, high-pressure washing or use of a heat
gun will speed the process. Heat blisters develop in
FRESHLY (within the first few days) applied coatings only.
When broken, they don't contain liquid and are not associated
with a surface defect that requires remediation. These
blisters may be removed by scraping and sanding. The
surface should be recoated under more favorable conditions.
How do you know if you have found the best contractor?
Great painting contractors make painting projects
easier. Here are some suggestions for successfully hiring
As interior and exterior painting continue to be among the most
common household remodeling projects, more and more homeowners hire
professional painting contractors. According to the National
Decorating Products Association, nearly half of all architectural paint
sold is purchased by professional contractors. Choosing a
reputable contractor is a very important decision homeowners must make.
It is wise for a homeowner to do some simple homework before signing a
Local paint stores can provide names of reputable and reliable painting
contractors. They want their customers to not only be happy with
their paint, but also with their contractor. After checking with
the paint store, start asking friends, co-workers and neighbors.
Most paint contractors know that if they do a good job, there is no
better source of new business leads than a happy homeowner.
After assembling a list of few possible contractors, itís time to
investigate the contractorís abilities. Think about the following
||Is the contractor well
||How long have they been in
||Can they provide proof of
||How many homes have they
||What type of paint do they use?
||Are they members of the Better
In addition to quality of work, several basic business questions
also should be asked. Homeowners should always make sure the
contractor has workerís compensation and liability insurance. If
not, the homeowner may be responsible for injuries that occur on the
job. The most important step is the one most often omitted, always
check references. Ask all references whether the job was finished
on time and within budget. Also, ask if they would use the
contractor again. Finally, put all terms and suppliers in
writing before the job is started. Try to determine if there is
something that each contractor does differently. Does one
specialize more in an area that is important to you such as siding
replacement or faux finishes. After all of the "interviewing" is
completed try to determine which contractor best fits your needs.
Remember that you get what you pay, for so unless you want a quick and
shoddy paint job, consider what you are getting and not who is the
cheapest. To see some references for Scott's Painting & Staining
Inc. check our references page.