Although most of our clients are concerned with the appearance and protection
of older homes, we are frequently contacted by owners of new homes experiencing
chronic exterior paint failure. It is important to know that this problem
can be solved.
New home builders can easily avoid paint failure problems by taking preventive
measures during the construction phase of a house. By following several
simple steps, homeowners can ensure a high-quality, long-lasting exterior
finish. Fortunately, this process seldom involves a major additional expense.
Owners of homes with existing paint problems will benefit from understanding
what causes their paint to fail. Once these causes have been identified,
they can be addressed, and future problems can be eliminated.
The most common reason for exterior paint failure in houses built since
the mid-1970s is energy efficient, airtight construction. It seems ironic
that in solving one problem, the conservation of energy, another was created
- peeling exterior paint. At the time these new, energy-efficient homes
were designed and constructed, architects and contractors did not realize
all of the consequences of these previously untested construction methods.
Recognizing that exterior paint problems have resulted from efforts to
construct energy-efficient homes, many builders have experimented with
inexpensive, frequently ineffective solutions to the problem. The most
common procedure is to install a "vapor barrier" between the
interior wall and the fully-packed insulation. While in theory this barrier
should be effective, it can only function well if installed without seams
and used in conjunction with constant interior dehumidification and/or
"dilution techniques." Dilution serves to introduce dry (cold)
exterior air in an effort to moderate the level of interior humidity.
We cannot help but note that these efforts involve a considerable use
of energy and capital in themselves.
The vast majority of exterior paint failures on modern homes occur in
the spring, near the end of the heating season. These failures invariably
result from a high level of interior humidity forcing its way through
the walls and coming into direct contact with the cold, unpainted interior
surface of exterior siding, where it condenses. The resulting condensation
soaks the wood. Failure may be uniform or limited to specific areas of
the home (normally sunny side exhibits the most severe problem as the
sun acts to "draw" the moisture against the exterior paint film).
Please note that exterior paint failure may also be a symptom of a much
more severe problem - the rotting of interior construction framework;
a frequent occurrence in the presence of moisture, warmth and darkness.
Modern homes are also much more likely to attract exterior moisture as
the capillary action in the laps (edges of siding and clapboards) draws
moisture into the house.
These problems associated with airtight construction are not encountered
in older homes where the wall cavities are either empty or partially filled
with insulation, thereby providing an air channel which allows interior
humidity to escape. Admittedly, these older homes are sometimes drafty,
and fuel consumption is greater, but they seldom, if ever, experience
exterior paint failure.
The interior humidity problem and its impact upon exterior painted surfaces
is further exacerbated by the broad range of moisture sources found in
the modern American home. Clothes dryers, dishwasher, saunas, whirlpools,
and frequent daily showers contribute to extremely high levels of interior
moisture release. A family of four can easily release twenty gallons of
water vapor into the interior of a home in a single day! While the human
body is quick to recognize gradients of ambient temperature, we do not
possess the natural ability to sense extreme levels of humidity. It is
unhealthy to reside in a high-moisture environment and yet entirely possible
for us to do so unknowingly until the paint begins to fall off the
The following recommendations, received from trade professionals, have
proven to be effective in correcting exterior paint failure.
Preventing the Problem - Pre-Construction Planning
- Deal only with reputable professions who acknowledge that special
planning is required in the design and construction of energy-efficient
- Insist that seamless vapor barriers be properly installed before wallboard
or plaster is applied. Effort should be made to avoid "leaks"
such as those which occur around wall switches and baseboard plugs.
- Consider the use of less insulation that your wall can accept - use
3" insulation with 4" studs, 4"-5" with 6"
studs. This will allow for an evaporation chamber. Your walls will retain
a much greater "R" value with 4" of dry insulation than
with 6" of wet insulation.
- Rather than nail your clapboard directly onto the sheathing of your
new home, consider installing it onto vertical furring strips in order
to provide an air space of at least 1/4" between the sheathing
and the back of the clapboard. As an alternative, please consider the
use of roll-type spacing material such as "Cedar Slicker."
- Eliminate the possibility of a moist basement by providing good water
drainage and sealing all exterior foundation walls.
- Install exhaust fans vented to the exterior in kitchen, bathrooms
and laundry room. Clothes dryers and Jacuzzis must have exterior venting.
Cover all standing water when not in use (hot tub/Jacuzzi).
- If possible, plan a well-vented crawl space and/or attic with at least
one sq. foot of ventilation area for every 300 square feet. The same
one sq. foot of ventilation should be provided for every 150 square
feet or crawl space. Crawl space and attic insulation must be installed
with the vapor barrier or foil side toward the living area.
- Specify that each piece of trim and siding to be used on the home's
exterior be primed on all "six" sides with Hollandlac or ECO
Primer/Undercoat before being nailing in place. All cuts should be sealed
by carpenters with one heavy, grain filling coat of primer/undercoat
immediately before nailing. Many lumber yards and mills offer "factory
priming." If you use this service, please insist that FPE primers
be used exclusively and confirm that they will not be over thinned -
many of these pre-coating firms use very low quality waterborne primers
whose sole attribute is quick drying. (Unless you are able to monitor
activity closely at the mill, we recommend priming at the jobsite.)
- Please note that homes heated with a ducted hot-air system are much
less likely to experience problems with humidity related paint failure.
- Prime the "top side" of all floor sheathing material used
between the first floor and basement with Hollandlac or ECO Primer/Undercoat.
Don't get unduly upset or plan on waging a successful legal battle with
your architect or builder. There are practical remedies. The following
are offered as options for your consideration:
Recommended Reading for Owners of Problem Homes
- Determine the location and degree of the problem. Keep in mind that
exterior paint failure is not the problem, but merely the solution.
A simple moisture meter will enable you or your contractor to measure
the existing level of moisture within your siding. Where failure is
particularly severe, we suggest that you arrange to have your home inspected
by a structural engineer or other person capable of measuring levels
of moisture in wall partitions. If these tests are conducted with the
correct instruments, there will be little impact upon the appearance
of your home. Ideally, testing should be conducted in late spring or
early summer when moisture levels will still be near their peak. Paint
application should not begin until after July 1.
- Install exhaust fans vented to the exterior in your kitchen, bathrooms
and laundry room. Ideally these devices will be tied into your lighting
switches so that they activate automatically when these rooms are occupied.
NEVER vent exhaust devices into an attic.
- Examine all crawl spaces and attics in order to bring them up to the
ventilation specifications indicated for new construction.
- Attempt to eliminate any sources of moisture infiltration from the
outside. A damp or leaky basement can frequently be corrected by installing
new external drainage and/or ventilation devices.
- Prime all interior sides of all exterior walls with Hollandlac or ECO
Primer/Undercoat. These alkyd primers will serve as "barrier coatings,"
drastically reducing the passage of water vapor from your home into
- Install a dehumidifier or air conditioner in your living area. Although
there is an expense involved in running this equipment, it will make
your home environment healthier and drier, and may save you thousands
of dollars in maintenance expenses.
- Do not, however, bring unseasoned firewood into your house, not even
in the cellar, as a cord of green wood can be expected to release more
than 200 gallons of water!
- Install vent plugs in siding channels or consider the use of the WedgeVent
System. The WedgeVent System is recommended in the event
that you are unable to obtain moisture levels below 15% by natural venting.
Use of WedgeVents can, however, create a wavy distortion in siding.
- Remove and replace exterior wood which has already begun to rot. Such
wood can normally be detected with a pocket knife. Avoid future problems
by encapsulating new wood as recommended in pre-construction steps.
- Do not allow snow or ice to maintain contact with exterior siding
for extended periods.
Finishes for Exterior Wood: Selection, Application and Maintenance,
by R. Sam Williams, Mark Knaebe, William Feist, 1996, 128 pp, $19.95; Forest
Product Society, 2801 Marshall Ct., Madison, WI 53705-2295; 608-231-1361,
Remedies for Common Paint Problems (flip cards), $25; The Rohm &
Haas Paint Quality Institute, Box 1248, Philadelphia, PA 19105-9965; 215-592-3179;