Homeowners FAQs
Topics:
Selecting a contractor
Q. I received three significantly different proposals from contractors. How should
I decide which contractor to select?
A. Clearly written proposals that are detailed and broken down into separate line
items are a good sign that the contractor is being thorough and has prepared an
accurate estimate. The following is a partial list of items your estimate or proposal
should include:
- The type of roof covering, manufacturer and color
- Materials to be included in the work, e.g., underlayment, ice dam protection membrane
- Scope of work to be done
- Removal or replacement of existing roof
- Flashing work, e.g., existing flashings to be replaced or re-used, adding new flashing,
flashing metal type
- Ventilation work, e.g., adding new vents
- Who is responsible for repairing/replacing exterior landscape or interior finishes
that are damaged during the course of the work
- Installation method
- Approximate starting and completion dates
- Payment procedures
- Length of warranty and what is covered, e.g., workmanship, water leakage
Also, be sure to read the recommendations listed in
A Homeowners Guide to Buying a New Roof (FYI) and
Guidelines for Selecting a Residential (Steep-slope) Roofing Contractor
for more information.
Q. I received several estimates to replace my asphalt shingle roof system and the
prices vary greatly.
A. If one estimate seems much lower than the others and it sounds too good to be
true, it probably is. Many fly-by-night contractors' below-cost bids seem attractive,
but these contractors often are uninsured and perform substandard work. If an estimate
is confusing, ask the contractor to break down the estimate into items/terms you
can understand.
Q. My contractor is offering a one-year warranty on my asphalt shingle roof system-is
that the industry standard?
A. Before answering the question, a clarification needs to be made about the different
warranties you will come across during your roofing project. First, there will be
the asphalt shingle manufacturer's warranty. In general, this warranty covers defects
in the manufacture of the shingle. The period of coverage can range from 20 years
to a lifetime. Please read NRCA's
consumer
advisory bulletin addressing roofing warranties for more information. Once
the project is complete, be sure the contractor provides you with a certificate
for your records.
Second, the roofing contractor will provide you with a warranty on his workmanship.
Typically, this will cover installation and related issues. The warranty should
contain what items are covered and what will void them. Many contractors offer one
year or two years of coverage; however, there is no industry standard.
Project problems
Q. My contractor just started working on my roof and it's the middle of winter! At
what temperature is it too cold to install asphalt shingles?
A. There are no specific temperature guidelines regarding when it is too cold to
install asphalt shingles. Asphalt shingles do become brittle in cold temperatures,
with fiberglass shingles more likely to break than organic shingles. Breakage can
be minimized or eliminated if the shingles are stored in a warm area and loaded
onto the roof a few bundles at a time. Another concern is that the self-sealing
strips will not seal or bond sufficiently in cold temperatures. Hand-tabbing (the
application of quarter-size dabs of adhesive to the underside of shingles) is recommended
if the building is located in an area prone to high winds. This will help prevent
the shingles from blowing off the roof until warmer weather arrives and the sealing
strips can set properly.
Q. Only the underlayment has been installed on my roof and it rained last night.
Now, the underlayment is wrinkled. Does it have to be replaced?
A. If the wrinkling isn't severe enough to affect the shingle installation (i.e.,
the wrinkling won't telegraph through the shingles and they won't appear buckled
or wavy once installed), the underlayment probably can remain in place. The effects
of wrinkling also will be minimized by using heavier weight shingles.
Q. My contractor installed the felt covering (underlayment) two weeks ago and hasn't
installed the shingles yet. How long can you leave underlayment exposed?
A. Time is not the critical issue; the condition of the underlayment is what's important.
Wrinkled or buckled underlayment should be replaced so the shingles lay flat.
Q. During the reroofing of my house, the contractor left one side of the roof unprotected
and when it rained, water entered the house and my ceiling and walls are damaged.
Who is responsible for repairing the interior of my house?
A. Before signing a contract, make sure that it contains language addressing who
is responsible for any damage that occurs as a result of the roofing work. All items
of concern and work to be done should be included in the contract.
Q. My contractor re-used the existing flashings on my roof and after he finished
installing the new shingles, he left! I've left several messages with the company
and no one will come back to install new flashings. Shouldn't that be included in
the work?
A. If the contract didn't specify the installation of new flashings, it wasn't included
in the original scope of work. Be sure that all items of work to be done are included
in the contract before signing it.
Technical questions
Q. What is the best asphalt shingle to use on my roof?
A. Asphalt shingle material performance depends of the quality, quantity and compatibility
of asphalt fillers, reinforcements and surface granules. There are two kinds of
asphalt shingles (based on the type of reinforcement mat used); fiberglass and organic.
Fiberglass shingles are more fire- and moisture-resistant than organic shingles.
Organic shingles have good wind resistance, high tear strength and can be installed
in colder temperatures.
Asphalt shingles should be in compliance with American Society for Testing and Materials
(ASTM) standards and applicable building codes. Fiberglass shingles should meet
ASTM D 3462, "Standard Specification for Asphalt Shingles Made from Glass Felt and
Surfaced with Mineral Granules," and organic shingles should meet ASTM D 225, "Standard
Specification for Asphalt Shingles (Organic Felt) and Surfaced with Mineral Granules."
Consumers also should keep in mind a roofing warranty's length should not be the
primary criterion in the selection of a roofing product or roof system because the
warranty does not necessarily provide assurance of satisfactory roof system performance.
See NRCA's
consumer advisory bulletin
addressing roofing warranties for more information.
Q. One contractor's bid includes No. 15 underlayment and another contractor says
he only uses No. 30 because it's the best. Who is right?
A. For asphalt shingles, NRCA recommends a single layer of No. 15 asphalt-saturated
underlayment be used with roofs having slopes of 4:12 (18 degrees) or greater. For
roof slopes between 3:12 (14 degrees) to 4:12 (18 degrees), NRCA recommends a minimum
of two layers of No. 15 underlayment. If you are installing a heavier-weight shingle
with a projected long service life, using No. 30 underlayment instead of No. 15
would be appropriate.
Q. Are two layers of No. 15 underlayment the same as one layer of No. 30 underlayment?
A. No. Two layers of underlayment are referred to as a "double-layer of underlayment"
and there is a 19-inch overlap between layers. One layer of underlayment is called
a "single-layer of underlayment" and there is 2 inches of overlap between layers.
NRCA recommends a double-layer of underlayment for roof decks having slopes of 3:12
(14 degrees) up to 4:12 (18 degrees).
Q. My contractor wants to use staples instead of nails to install my asphalt shingles.
Is that okay?
A. NRCA recommends galvanized steel or the equivalent corrosion-resistant roofing
nails for asphalt shingle installation. Also, verify the governing building code
requirements and what the shingle manufacturer recommends.
Q. My contractor suggested installing a ridge vent on my roof and I already have
two single static vents. Do I really need a ridge vent?
A. NRCA suggests the amount of attic ventilation be balanced between the eaves and
ridge. The intent of a balanced ventilation system is to provide nearly equivalent
amounts of ventilation area at the eave/soffit and at or near the ridge. For a balanced
ventilation system to function properly, approximately one-half of the ventilation
area must be at or near the ridge.
Proper attic ventilation is one of the least understood concepts in residential
roofing. To learn more, read "
Principles of Attic Ventilation" an article by Mark Graham,
NRCA Associate Executive Director of Technical Services, that appeared in NRCA's
magazine,
Professional Roofing or see
Technical Bulletin 98-2.
Q. My house has a roof with a 2 1/2:12 (11 degrees) slope. The manufacturer says
it's okay to use asphalt shingles, but my contractor says it isn't. Who's right?
A. There are some manufacturers (and even model building codes) that will allow
the application of asphalt shingle roof having that slope; however, NRCA does not
recommend shingles on slopes less than 4:12 (18 degrees). Asphalt shingle roof systems
are watershedding and rely on gravity and roof slope to effectively drain water
off the roof.
Q. My house has a flat roof. What is the best roof system for a flat roof?
A. There is no one roof system that is best for all applications. Keep in mind that
even if you are using the best materials, your roof system still can be installed
improperly and you could end up with a leaky roof. Good workmanship and proper attention
to detail (e.g., flashing and drainage issues) are just as important as material
selection. Also, maintenance plays an important role in roof system integrity and
service life.
To assist you in your decision-making, homeowners should be informed of what is
available. Please refer to the Roof System Types page to learn about the different
low-slope roof systems.
Also, keep in mind low-slope roofing materials manufacturers may not offer material
warranties to homeowners. The only warranty you most likely will be able to obtain
is from the contractor. So it is critical you work with a professional roofing contractor
and get a detailed, thorough proposal. Be sure to read the recommendations listed
in
A Homeowners Guide to Buying a New Roof
(FYI).
Maintenance questions
Q. How can ice dams be reduced or removed?
A. Remove as much snow as possible, but call a professional roofing contractor if
your roof is steep, the snow is deep or the ice is thick. NRCA does not recommend
using ice picks or shovels (or any tool with sharp edges) because there is a chance
of damaging roof coverings and flashings. NRCA also does not recommend hosing down
a roof with water or use of a hot air gun. Electric heat cables generally have limited
effectiveness.
Q. Can ice damming and backup occur without gutters?
A. Yes, and it is more probable for roofs with lower slopes, especially in valleys
and upslope from curbs, chimneys and penetrations.
Q. I want to use melting pellets to melt the snow on my roof. Will it harm the asphalt
shingles?
A. Generally, chemical melting compounds do not reduce the overall expected service
life span of asphalt shingles. Staining may occur until all the residue is washed
away. Calcium or magnesium chloride pellets are less harsh and stain less than sodium
chloride.
Q. How do I clean algae and moss from my asphalt shingle roof?
A. Use a mild solution of chlorine bleach and water or mild detergent gently applied
with a sponge or hand-held sprayer and rinse thoroughly. Do not use a power washer
or high concentrations of bleach, and do not scrub the shingle surface. The
Asphalt Roofing Manufacturers Association also offers cleaning
recommendations.