Five myths of roofing
Other Columnists
When it comes to protecting the home, it's what's on top
that really counts. On top, as in the roof.
It's the home's first level of protection - against sunlight, rain, snow
and wind - but the last thing a homeowner usually thinks about.
"No one thinks anything of the roof until it leaks," says Bill Good,
executive vice president of the National Roofing Contractors Association, an
Illinois trade group.
Unfortunately, when a roof goes bad, it can be one of the homeowner's
biggest - and most expensive - headaches. A leaky roof often means interior
water damage, so there are phone calls to the insurance company and a
restoration contractor.
A typical roofing replacement job on Long Island, which includes tearing
off the old roof and installing a new layer of asphalt shingles, runs about
$6,000, says Keith Kaval, co-owner of two companies that specialize in roof
replacement - Tim White Remodeling in Lindenhurst and Garden City Aluminum &
Roofing. "That figure is for a shingle with a 30-year rating," he says. It
doesn't include replacing sheathing, fascia boards or soffits, all areas that
might have rotted away, or new gutters.
Hold on. What do sheathing (the wood underneath the shingles) and fascia
boards (where gutters hang) have to do with roofing? A new roof means simply
replacing shingles, right?
Wrong. The roof is one of the home's most important "systems." It's how an
exterior shell sheds moisture. Home systems, like plumbing and electrical, are
several components working together to perform a larger series of similar
tasks. A roofing system primarily consists of the following:
Wood sheathing: This is also called the deck.
Underlayment: This is typically a fiberglass-reinforced paper that helps
shingles lay flatter and keeps the wood deck dryer.
Leak-barrier membranes: These prohibit water intrusion, including
ice-damming, at critical spots, such as the roof's outer and inner edges and in
valleys.
Flashing: Metal material formed to stop leaks at vents, pipes and other
objects that extend through the deck.
Ventilation: Fresh attic air prevents mold and moisture from damaging the
underside of the sheathing and keeps homes cooler during warm weather.
Shingles: The exposed layer that battles the elements, especially wind and
water.
So, to say roofing is just shingles is like saying plumbing is just water
or electrical is just outlets. Yet, far too many homeowners consider a new roof
simply a new layer of asphalt shingles. In fact, most think it's OK to cover
an existing layer with a new layer of shingles.
In their lifetimes, homeowners might purchase just one new roof. Making
poor decisions on such an important protective barrier can lead to moisture
problems, either inside walls or above ceilings, and structural damage.
With that in mind, here are five myths about roofing that every homeowner
should understand.
WRITE TO: Gary Dymski, 235 Pinelawn Rd., Melville, NY 11747-4250 or e-mail
Gary.Dymski@newsday.com
1. It�s OK to cover an existing layer of shingles with a new layer
Don't do it, even though nearly every local building code says it's acceptable.
Think of shingles as the skin of an apple. Ever bite into that bright red
skin only to get a mouthful of a soft, bruised, mushy interior?
Underneath shingles is a layer of wood sheathing, usually plywood.
Sheathing can rot because of leaks, inadequate attic ventilation or just age.
The best way to inspect this critical layer is to strip away the old shingles.
"Other than saving money ... there's no good technical reason to add a layer
of shingles to an existing layer," Good says. "It's always better,
technically, to tear off the old roof. "
Kaval agrees, "If you don't remove the existing layer, all you are doing is
putting a new cover over a failed roof. Without inspecting the sheathing
underneath, the roof is sure to fail again. "
Another issue, says Good, is weight load. Having three layers of shingles
on a roof adds weight and can damage sheathing and roof trusses.
2. All asphalt shingles are basically the same
Today's laminated and fiberglass-reinforced products are better than ever.
Shingles are rated for durability - some are warranted to last 50 years - and
wind resistance (up to 110 mph). Manufacturers, such as GAF and CertainTeed,
offer limited lifetime warranties.
And, boy, are there choices. Some shingles are made to combat specific
problems. For example, in humid areas like Long Island, some roofs, over time,
show a black mold. Algae-resistant shingles contain imbedded granules of zinc
and copper, which, when mixed with roof water, are natural algaecides. Other
shingles are manufactured to look like wood shakes or slate tiles.
"Technology is growing so fast," Good says. "Now shingles are being made that
have reflective properties. Granules contain substances that reflect sunlight
away from the house. This means roof shingles can help keep attics cooler. What
you have is a shingle with energy-efficient properties."
3. Flashing needs to be replaced only when a new roof is being installed
Flashing, the metal material fabricated to divert water away from vents, pipes
and other roof openings, including chimneys, is its own, separate animal. It
can lay in place for years and can protect even longer than other components of
the roof. Or it can fail in months and otherwise ruin a perfectly sound
roofing installation.
As a rule, flashing should be checked every six months. A visual inspection can
be made with binoculars. Look for dried caulking or sealant, cracked or broken
flashing pieces and damaged shingles in contact with the flashing.
If a visual inspection turns up potential problems, have a roofing contractor
climb the ladder for a better look or to make repairs.
4. Attic insulation saves energy and helps roof performance
Adding more than the required insulation can block ventilation openings at the
soffits and eaves and might trap moisture. Trapped moisture can warp and rot
sheathing from the attic interior and also can be a source for mold. Actually,
there is a special relationship between insulation and ventilation.
Insulation is rated by thermal resistance, called R-value, which indicates
the resistance to heat flow. The Department of Energy recommends that attic
insulation in the Northeast have a minimum R-value of 49. The higher the
R-value, the greater the insulating effectiveness.
Determining existing R-value is based on the type of insulation material and
its thickness. For example, the most common attic insulation in new homes is
fiberglass blankets or batts that are about 16 to 17 inches thick. The
fiberglass has an R-value per inch of 3.2; the result is an insulation layer
with an R-value of between 51 and 54. Increasing the R-value with another
layer of fiberglass would seem to be logical. However, adding insulation can
vary the temperature at the wall, possibly creating condensation inside the
attic.
Proper ventilation eliminates moisture buildup and maintains steady attic
temperatures, in both cold and warm seasons. A rather complicated formula is
used to determine ventilation requirements. The important concept is that
ventilation requirements are related to the area of the attic floor.
"The rule of thumb is for every 150 square feet of attic floor space, you
need one square foot of net free area," says Joan Crowe, a technical services
manager with the roofing contractors association.
Ventilation devices, including fans, vents, louvers and ridge venting, are
rated in square inches for net free area (NFA). Crowe says two things are
crucial to proper ventilation: Any added insulation must not block ventilation
openings at the eaves and soffits, and ventilation must be equally divided
between the eaves and soffits and the roof ridge.
Signs of inadequate ventilation are ice-damming, mold on the underside of
the sheathing and excessive frost accumulation on the roof deck or in the
attic.
Ask your contractor how ventilation requirements were calculated. Or you
can figure it out at www.gaf.com. Click first on the "Residential Homeowner"
link, then "Learn about Roofing" and "Why Use a System. " When the roof diagram
appears, click on "Attic Ventilation."
5. Gutters are separate from the roofing system
Roofs are designed to divert water from the structure. The gutters are the
final piece of the process; they prevent water from dripping down exterior
walls and move it from the foundation. It's why many roofing installations can
include new gutters and downspouts.
"I find that 90 percent of roof leaks are gutter-related," Kaval says.
At the very least, clean gutters of debris, sediment and leaves regularly.
Repairing damaged runs might be as easy as tapping in a few gutter spikes with
a hammer or reattaching downspouts with a riveting tool. Clogged and sagging
gutters can cause leaks behind exterior walls and contribute to ice-damming.
Over an extended period, a faulty gutter system can rot away fascia boards,
soffits and the sheathing at the roof's edge.
SOURCE: NATIONAL ROOFING CONTRACTORS ASSOCIATION
ONLINE SOURCES
More than 80 percent of home roofs nationwide are covered with asphalt
shingles. Other common roofing options include wood shingles, slate tiles and
metal. Here are some online roofing resources:
Asphalt: GAF Materials Corp. (www.gaf.com); CertainTeed
(www.certainteed.com); Owens Corning (www.owenscorning .com); Elk Building
Products (www.elkcorp.com); National Roofing Contractors Association
(www.nrca.net)
Wood shingles: Cedar Shake & Shingle Bureau (www.cedar bureau.org)
Metal: Metal Roofing Alliance (www.metalroofing.com)
Slate tiles: National Slate Association (www.slateassociation .org)
A LICENSE TO CLIMB ...
Here's the No. 1 tip on hiring a roofing contractor: Choose one who is licensed
and insured.
An experienced contractor will have the proper equipment and training to
work safely on a rooftop, says Bill Good, executive vice president of the
National Roofing Contractors Association.
The 120-year-old, Illinois-based trade association has a wealth of
information geared to homeowners, including steps for hiring a qualified
contractor, online at www.nrca.net.
But Good has a story about one homeowner who did not hire a properly
licensed and insured contractor. It seems that one worker was atop the roof
laying shingles and the other was at ground level. The worker on the roof,
perhaps concerned about falling, had tied one end of a rope around his waist
and the other around the bumper of the company truck. It seems the worker on
the ground had an errand to run, so he took a break and drove away in the truck.
"The homeowner was found liable, in this case," Good says, "because the
contractor was not properly insured."
There are other reasons for hiring experienced contractors, including the
new technology in roofing materials and systems.
"Most manufacturers today are developing roofing systems," says contractor
Keith Kaval, a member of the New York-Long Island chapter of the National
Association of the Remodeling Industry. In order to properly install such
systems, manufacturers require contractors to complete training courses.
Manufacturers such as GAF and CertainTeed certify contractors who use their
products. Each manufacturer has a roof-warranty program that covers both labor
and materials. "Homeowners should know that hiring the least-expensive
contractor doesn't necessarily mean they are hiring the best contractor," Good
says.
-Gary Dymski
