Familiarize yourself with the elements of your roof and with the language
of roofing. Click here for
a glossary of terms.
Get at least several bids for any major roofing job. Prices from different
companies for the same work often vary by 100 percent, which may represent
thousands of dollars of difference.
Use estimators as your consultants, getting feedback from each to decide
exactly what needs to be done. Then go back to each with the final description
of what you want so each can bid on the same job.
Use our ratings of area roofing contractors, shown on our Ratings Tables,
to find high-quality companies.
Before using any contractor, ask it for proof that it is licensed and that
it has liability and workers' compensation insurance.
Get a copy of the warranty from the manufacturer of whatever roofing materials
are used. Also, get a warranty on the roofer's work, ideally for five years
or more; have the roofer write into your contract: "in addition to all
other warranties, if roof leaks within [five years, or better still, 10
years], except as a result of accidental damage, contractor will bear the
cost of labor and materials to eliminate all leaks."
Get a fixed-price contract. Specify by picture or words exactly what roof
areas are to be covered. Specify other details such as whether old shingles
are to be removed, whether flashings are to be replaced, who is responsible
for cleaning up and hauling away debris, and exactly what types and weights
of materials are to be used.
Arrange to pay for the work as late in the process as possible. Over half
of the contractors we surveyed will allow customers to withhold all payments
until work is complete. Try to arrange to withhold at least a portion of
the price until your roof has been tested by some stormy weather.
"Well, at least we've got a roof over our heads."
Yes, there's nothing more basic than the shelter a roof provides. It keeps
the rain out and the heat and air conditioning in.
Fortunately, roofs are quite durable and will protect you from the elements
for a long time before needing replacement. But eventually work will be
needed. When it is, the cost will likely be steep. And unless you make
your roof purchase carefully, you may spend thousands of dollars more than
necessary and get less-than-satisfactory results.
These are just a few of the hundreds of roofing horror stories we have
heard from our subscribers—
"Absolutely terrible. New roof leaked after a year and a half. Took NINE
months for them to finally deal with problem. Would always claim they would
call back tomorrow. NEVER did."
"Claimed we needed to replace a roof that did not and had never leaked.
Seemed like a con job."
"The final bill ended up several times higher than the initial estimate...
Less than a year after the completion of the service, rain water dripped
through the ceiling into one of the bedrooms in the middle of the night...
They didn't return our messages for several days. After we finally got
hold of them and they were scheduled to come and inspect the damage, they
did not show up. When they finally did inspect the damage, we were told
that they had not used the correct material when they performed the service
the first time...that we would have to pay the difference in cost of material
this time despite...warranty."
"Gave them one-third down when signing the contract. A BIG mistake. After
three months of delays, they increased the price by 30 percent..."
"They were two months late getting started and I had a lien placed on my
property by the shingle supplier because they didn't pay them on time.
They were very rude...."
"The first big rainfall we had, my roof leaked. I called them several times
to make repairs, they put me off over and over again, and never came to
Even when things don't go horribly, there are all too many minor annoyances—months
of waiting (with pots catching drips) for contracted work to begin, work
having to be redone, uneven rows of shingles, poor clean-up of nails and
debris, and damaged landscaping, for example.
The key to success is to find a good roofing contractor, agree in writing
on exactly what will be done, and keep a close eye on the job as it progresses.
Although the roofing business is one where costly mistakes are too common,
fortunately, there are many excellent roofers in the area—and the highest
rated companies are as likely as any to do your work at a low price.
We'll discuss how to choose a roofer, how to deal with the roofer you select,
and steps some homeowners may be able to take to avoid or delay the need
for expensive roofing work.
Our Ratings Tables give ratings of local roofing contractors. The table
shows which areas the contractors serve and which of the major types of
roofs each company works on.
The way most consumers select a roofer or other home-improvement contractor
is by asking friends or neighbors for recommendations. Unfortunately, getting
a few recommendations is not a sufficient basis for a reliable judgment.
Almost all service companies do satisfactory work some of the time, but
you don't want to be among the one-in-five unlucky ones. You want to know
about the companies that do very good work consistently. The ratings from
our surveys of CHECKBOOK and Consumer Reports subscribers, shown on our
Ratings Tables are a way for you to check with over 2,000 of your neighbors
for their opinions on area roofers. (For more information on our customer
survey and other research methods, click here.)
And these ratings are not subject to the kind of manipulation by the companies
themselves that is all-too-common with the comments often found on the
A number of the roofing outfits on our Ratings Tables were reviewed
very favorably by a high percentage of their customers. At the time of
our last full, published article, thirty-eight of the companies were rated
"adequate" or "superior" overall by 95 percent or more of their surveyed
customers; 27 were actually rated "superior" overall by 90 percent or more
of their surveyed customers. Unfortunately, however, substantial numbers
of the customers of some of the outfits listed on our Ratings Tables
regretted their choices: 15 of the companies were rated "inferior" overall
by at least 15 percent of their surveyed customers.
On our Ratings Tables, for firms that were evaluated in our last full,
published article, we show counts of complaints we gathered from local
Better Business Bureaus (BBB) for a recent three-year period. Where we
were able to, we have also reported on our ,Ratings Tables a complaint
rate for each company, calculated by dividing the number of complaints
by our measure of the number of full-time-equivalent employees who perform
residential work for the companies. These complaint rates are intended
as a rough way to take into account volume of work and the fact that companies
that do more work are exposed to a greater risk of incurring complaints.
You can check current BBB complaint information on any company by contacting
the BBB where the company is located (see below for contact information).
On our Ratings Tables, in the details under our listing for the company,
click a link to the local BBB to go directly to the BBB's most up-to-date
report on any complaints about the company.
One way to cut the risk of being dissatisfied is to arrange to pay for
most or all of the work only after the job is completed. In California,
a roofer cannot require a downpayment of more than the lesser of 10 percent
or $1,000. But home-improvement contracts can still require that larger
portions of the contract be paid once work begins. Holding back additional
payments—or all payments—until work is completed gives you leverage to
ensure that work is done properly and on time. Our Ratings Tables show
what percentage of the contract price on a $5,000 roof installation job
each company "ordinarily" allows the customer to pay at completion or later.
About one-half of the companies allow you to hold back the entire amount
until completion, but some require that at least half be paid earlier.
It's well to think in advance about additional leverage you'll have if
you are not satisfied with a contractor's performance. A company may seem
conscientious and cooperative now but prove to be a bit harder to live
By choosing a contractor that is licensed, you ensure that licensing authorities
will have the threat of license cancellation as one form of leverage in
working to resolve a dispute. You also enhance the chances that the authorities
will feel you deserve their help—because you have taken the care to choose
a licensed contractor. Ask any contractor you are seriously considering
for proof of a currently valid license; then verify by calling the Contractors
State License Board (CSLB) at 800-321-2752 or by checking CSLB's website
at www.cslb.ca.gov. In California, any roofing job costing $500 or
more must be performed by a licensed contractor.
An additional advantage of dealing with a licensed contractor is that if
it fails to perform under your contract, you will be able to seek compensation
through CSLB's complaint process. One of the conditions for being granted
a license is that the company must maintain a bond of $12,500. If the Board's
inspectors find that a customer is due money back from a roofing contractor,
the contractor can be ordered to pay; if the contractor fails to do so,
its license can be suspended or revoked and the customer is allowed to
make a claim against the bonding company.
There is a statute of limitations on complaints to the Board: four years
from the time of the work in the case of patent defects (flaws that are
easily discoverable) and ten years in the case of latent defects (those
that are not readily discoverable). You generally must file your complaint
within these times in order for the Board to be able to take action on
your behalf. But if a contractor provides you with a workmanship warranty
for a period longer than the time specified in the statute of limitations,
you can press your claim through the Board for the full period of the warranty.
A $12,500 bond will be enough to cover the costs of most individual roofing
jobs. But if a company goes bankrupt, there are likely to be other claims,
and the bonding company's total liability is limited to the amount of the
bond. Wages of the company's workers will be paid first; then the bonding
company will divide the remaining funds among all claimants, pro-rated
according to the amount of their claims.
If a third party is injured by a contractor working on your home, or if
one of the contractor's employees is injured, you might be liable. The
best protection is to be sure the contractor has liability and workers'
compensation insurance. Before signing a contract, require that the contractor
show you current "certificates of insurance" for both liability and workers'
compensation. Insurance companies readily issue such certificates. Alternatively,
ask the contractor to provide you with contact information for its insurance
agent so you can verify that the contractor's insurance policies are up-to-date.
You want to be sure your roofer will be around to finish the job and that
you won't be left fending off the company's creditors that wish to place
a lien on your house.
A good way to assess financial soundness is to get—and check—references.
Ask for the names of major materials suppliers. Then ask suppliers how
much credit is commonly extended and what the contractor's recent payment
performance has been.
You can also drive by to take a look at the contractor's place of business
and you can check how long the company has been in operation. An easy way
to check back a few years is to look at an old phone book. (We recommend
keeping an old phone book so you'll be able to check on various types of
companies you might use.) Or you can check with the Better Business Bureau.
If your roof has been damaged in a storm, be wary of contractors who appear
out of nowhere and offer to help. There are scads of roofers who make their
livings chasing storms—traveling from area to area in search of easy-to-obtain
business. Some of these companies do good work. But many do not, and if
your newly repaired roof begins to leak a year or two later, you might
find it hard to track down the out-of-area contractor.
You may get two types of warranties on roofing work: a warranty on materials
from the manufacturer and a warranty on workmanship from the roofer. Many
manufacturers also offer extended warranty protection.
The materials warranties offered by the major shingles manufacturers are
very similar. Asphalt composite shingle manufacturers, for example, agree
to pay for the cost, including labor, of repair or replacement of shingles
proven to be "defective." The duration of the warranty varies with the
quality of shingles you buy. A manufacturer's warranty generally begins
with a specified period of time (for instance, five years) during which
the warranty covers the entire cost of replacing defective shingles. After
that initial period, the manufacturer's exposure is reduced on a pro-rata
basis each year for the remainder of the warranty's duration.
Roofers' warranties of their labor are often much less well spelled out.
Some simply say "labor guaranteed for X year(s)." Others say "guaranteed
against defects in workmanship for X year(s)." It's not clear whether these
statements mean that you will recover costs or have work redone for free
only if you can prove that the work was done improperly, or whether it
is enough merely to show that the roof leaks. It's also unclear whether,
if the workmanship is defective, the contractor must provide only labor,
or must also provide required materials.
You'll be better protected if you find a roofer that will let you write
into your contract in addition to all other warranties: "If roof leaks
within X year(s), except as a result of accidental damage, contractor will
bear the cost of labor and materials to eliminate all leaks."
Roofers' warranties most often run for one to two years, but some are for
five years or more. Most have different warranties for different types
of roofs, and shorter warranties for repair jobs than for roof replacements.
To supplement roofers' warranties—and to protect against roofers going
out of business and not being around to honor their warranties—most manufacturers
now offer extended warranties that cover workmanship. To buy one of these
warranties, you have to use a contractor that has been approved by the
writer of the warranty, which usually involves a check on proper licensure
and insurance coverage. Also, the warranty seller will require that the
roof be installed according to proper specifications (adequate ventilation,
premium felt paper, extra protection at locations of likely leaks, etc.).
Extended warranties usually cost $4 to $10 per 100 square feet of the roof,
depending on the length of the warranty. If your roof measures 2,500 square
feet, and a typical, 20-year extended warranty costs $10 per 100 square
feet, you'd pay $250 extra for it. As with most other extended warranties,
CHECKBOOK is skeptical that the value of these manufacturer-offered warranties
justifies the cost, but they do represent an additional form of protection.
The quality of a roofer's work and its financial responsibility should
be your primary considerations. No price is a bargain price for a roof
that leaks or looks unattractive or that is simply never installed. But
once you have identified roofers that measure up on these quality factors,
price becomes critical.
You will want to have roofing work done on a fixed-price basis, following
We worked with a few subscribers to get bids on roofing jobs for their
homes. So much as possible, each subscriber had all the roofers bidding
on his or her home bid on the same specifications. The roofer-to-roofer
price differences on the same job were striking.
Table 1 gives examples of different roofers' bids for several of these
subscribers' jobs. For one of the jobs, prices ranged from $4,495 to $13,344—a
difference of more than $8,500. For another job, the roofers' price quotes
ranged from $6,600 to $12,950—a difference of more than $6,000.
The message is obvious: get several bids.
Get your bids from companies that rate high for quality. Our experience
with roofing bids over the years has revealed very little pattern: contractors,
including high-quality contractors, may have high prices on some jobs and
low prices on others. There is not much price-quality relationship.
We can't give you a firm rule as to exactly how many bids you should get.
There is no way to know in advance whether the next bid will be lower than
others—a second bid might save you thousands of dollars or might be higher
than the first bid and thus save you nothing. Likewise with the third bid.
Figure 1 illustrates expected savings from getting additional bids based
on tests we have done getting multiple bids to replace an average-size
asphalt composite shingle roof.
The likely gain by increasing from two bids to three bids is, of course,
smaller than the expected gain by increasing from one to two bids. Increasing
from three bids to four bids can be expected to be even less productive.
Naturally, the shape of a curve like the one in Figure 1 would be different
for different jobs. But for many jobs, the likely savings from getting
three, four, or more bids will readily justify the time required.
Figure 1—How Much a Typical Consumer Might Expect to Save By Getting More
than One Bid on a Re-roofing Job
Here are a few guidelines on getting bids:
Invite out more companies than you really care to see. Some won't show
up for months, if ever. When you've seen enough, simply call the remaining
contractors and cancel. During some periods, especially after a roof-damaging
storm, you may have to invite many contractors to get even a few to appear.
Use estimators as your consultants. When getting your first few bids, you
probably won't know exactly what work is needed. So ask each contractor
for its suggestions and the reasons behind them; then weigh the arguments
and settle on your own set of specifications.
Once you have a tight description of your specifications, call back the
contractors that have already bid on your job and ask them to adjust their
bids accordingly, and give a copy of the specifications to any additional
companies you wish to have bid.
You probably don't have to be there to meet with estimators unless you
need to point out water damage occurring inside your house. If you won't
be meeting with estimators in person, make sure to leave copies of your
Get more bids on larger jobs. If you can save 20 percent on a $10,000 job,
that's $2,000, but a 20-percent saving on a $500 job is just $100.
Get more bids if the difference between the first two or three bids is
Get more bids on jobs where labor, rather than materials, makes up a large
portion of costs. Contractors pay roughly the same amount for materials,
but they may differ significantly in what they charge per hour for labor
and in how much their workers can accomplish per hour.
Get more bids if it's easy—for example, if you'll be home anyway or if
you can arrange for the roofer to see the job without you there.
For small repair jobs, some contractors work on a time-and-materials basis.
Avoid this arrangement, if possible; you're much safer with a fixed-price
contract. But if you must pay by the hour, check the hourly labor rate,
how many workers are included in the rate, the minimum charge, whether
you'll be charged for travel time, and how partial hours are rounded. You'll
find getting this information is like pulling teeth.
It's not enough to choose a good roofer. To get the roof you want, when
you want it, at the best possible price, you must also deal with contractors
Be sure you know what you need.
Inspect your roof carefully. Does it all need to be replaced or are parts
of it newer, in better shape? Are the gutters in good shape? How about
the flashings? Is there rot in the fascias or sheathing? Is your attic
properly ventilated? You can get free help from each estimator you talk
with; each may point to slightly different remedies. To make your shopping
meaningful, you will want estimates on about the same work from each company,
but you will also want to ask for their proposed variances from the basic
work plan, the reasons for these variances, and the effects of the variances
Figure 2—Parts of a Roof
Familiarize yourself with the language of roofing. This figure will help.
Specify in your contract exactly what you want done.
The proposals estimators give you will often be imprecise. Simply add your
own specifics before you sign. For example, for an asphalt composite shingle
Specify, by picture or words, exactly what roof areas are to be covered.
Indicate whether or not old shingles are to be removed. The reasons for
removing old shingles before applying new ones are, first, that additional
layers may overload underlying sheathing and structural lumber—especially
if you will be getting new heavy-weight architectural shingles—and, second,
that old shingles can become warped as they dry out and age, causing new
shingles to appear uneven. For these reasons, most of the local codes prohibit
application of more than two layers of shingles except in unusual circumstances,
and roofing over old shingles is less common than it once was because most
manufacturers' warranties won't cover shingles laid over old ones. On the
other hand, it costs less to roof over than to remove old shingles before
If shingles are to be removed, indicate that a new layer of felt is to
be applied under the shingles as required by local codes. Also indicate
the type and weight of the felt.
Specify the types of shingles to be used—their make, color, shape, wind
resistance, and weight. Light colors tend to absorb less heat from the
sun and may therefore last longer, but there's no hard evidence on how
much longevity you gain, and dark may look better on your house. Instead
of the simple, flat, three-tab shingles that were the roofing staple for
decades, many homeowners are now selecting "architectural," or "dimensional,"
shingles. These shingles are layered, cut, and colored to give more depth
and shadow lines and to look more like slate or wood shingles or shakes.
You will want to see an actual sample of the specific make, color, and
style of shingle that the contract specifies.
Specify the warranty on the shingles. Using shingles with a 30-year warranty
rather than a 20-year warranty might cost you a little extra but might
spare you or the next owner from facing the cost of labor and materials
for roof work for an extended time—although we have been unable to find
scientific evidence that 30-year shingles will really last significantly
longer than 20-year shingles. Architectural shingles are generally heavier
than simple, three-tab shingles, and often have warranties of 40 years
Indicate which, if any, flashings are to be replaced, which are simply
to be reused, and what materials are to be used. Unless the contract says
so specifically, a roofer is not legally required to repair or replace
flashings. If you have copper flashings now, most experts recommend that
you leave them. Aluminum flashings, on the other hand, are often replaced
since they are frailer than copper and cost less. Be sure to specify whether
replacements are to be aluminum, copper, or some other material—and what
weight they will be. If flashings are to be copper, insist on at least
16-ounce (per square foot) material, and try to get 20-ounce material for
valleys. If flashings will be aluminum, insist on at least 0.032-inch thickness.
The heavier the flashings, the less the chance that they will be damaged
on installation or will erode away, and the greater the possibility that
they will be reusable in the future. You'll also want to specify what width
of flashing is to be used to ensure it will protect the slope and angle
Specify whether any ventilation is to be added. Proper ventilation of your
attic allows the water vapor that rises through your house to be released,
reducing the chance of rot. Also, in the summertime, good ventilation of
hot air from your attic might keep your house cooler. You'll want to press
roofers to explain their recommendations regarding ventilation. There is
debate in the industry as to how much ventilation is desirable. Local building
codes specify minimum ventilation requirements. The best approach usually
is to put vents in both ridges and soffits. A good system will include
vents that will allow cold air in under the entire roof and good insulation
above ceilings to keep warm air in the house from entering any space immediately
beneath the roof.
Specify whether the shingles are to be algae-resistant. Growth of algae,
especially in damp and shady areas, can be an eyesore. Shingles can be
manufactured incorporating tiny flecks of zinc or other materials that
retard algae growth. Algae can be treated after the fact by washing down
the roof with readily available chemicals—but choice of resistant shingles
can help you avoid having to do that.
Specify that the contractor is responsible for a complete cleanup. Remember
that nails and cuttings of flashings will be hard for you to clean up and
can be a hazard. Many contractors use magnetic devices to pick up metal.
You may want to require a daily cleanup—so the area won't be a mess for
the period of the work, and so you can see early on how well the roofer
cleans and be prepared, if necessary, to supervise carefully. Poor cleanup
is a problem cited again and again by subscribers we survey.
Write in a requirement that the contractor will haul away all debris; otherwise,
you may be stuck with messy piles and no legal right to make the contractor
remove them. It costs a contractor about $100 to haul away shingles removed
from an average-size roof.
Indicate whether metal drip edges are to be installed at the eaves and
the rakes. These edges, which prevent water from curling back under the
shingle edge to reach the wood, are generally a good investment, at about
$1 to $2 per linear foot.
Be similarly specific on other types of roofs. For example, say what grade
of shakes or shingles is to be used on a wood roof, the exact make and
composition of concrete or synthetic shingles or tiles, how many layers
and what kind of stone is to go on a built-up roof, what type and weight
of metal and paint are to be used on a metal roof, and what materials and
application techniques are to be used on a modified bitumen or single-ply
Determine if your roof work requires a permit and inspection; if so, specify
in the contract that the company must secure a permit and that the work
must be inspected and approved before final payment.
Check with your local building inspection office to determine whether a
permit is necessary for your roof work.
Indicate in the contract when work is to begin and how long it is to take.
Given frequent customer dissatisfaction with delays (as reflected in our
customer survey findings), you will want to have the right to get out of
a contract and find another roofer if your original contractor proves too
Spell out a fixed price for the work to be done and the formula for covering
You should be able to get a binding contract at the price your company
gave you in its estimate. Most companies, however, will insist on a loophole
for the possibility that they will find damaged fascias, sheathing, or
structural lumber. Most of the contracts we have collected simply stated
that the required carpentry would be done on a "per foot" or a "time and
materials" basis. You should be sure your contract states how charges will
be figured. Typical is a charge per square foot, or per linear foot.
Seek to pay for your work as late as you can, and indicate in the contract
what the schedule of payments is to be.
About half of the roofers we surveyed will allow you to pay nothing until
your entire job is completed. Although companies have their standard policies
on payment scheduling, most will bend to accommodate a customer with good
credit standing. In particular, never let your payments get ahead of the
completed work or pay in full until the job is completed. Press for enough
leeway in your payment schedule so that your house is likely to have to
face some stormy weather before final payment is due.
Be sure that the contractor carries workers' compensation and general liability
Before you sign a contract, ask to see certificates of insurance. If the
insurance documentation is not available at the time you wish to sign,
you can write into the contract: "Contractor is required to provide homeowner
with certificates of workers' compensation insurance and personal liability
and property damage insurance. Work is not to commence, and no payments
are required, before such certificates are provided." In addition, it's
a good idea to write in a statement that you "will be held harmless for
any damages which would be covered by general liability or workers' compensation
Specify in the contract whether any subcontractors will be used and, if
so, who they will be.
Say in the contract: "no subcontractors other than those listed are authorized
to do work on homeowner's premises, contractor is not authorized to give
any other subcontractors access to homeowner's premises, and homeowner
is not liable for payment to any other subcontractors."
Arrange to pay for work only after you have evidence that subcontractors
and suppliers have been paid.
A subcontractor, supplier, or worker may be able to get a lien on your
house if the roofer does not pay for labor or materials used. To protect
against that possibility, you can write into your contract: "Prior to each
payment, contractor must provide homeowner lien releases covering work
to which the payment applies. Each release must state the name of the company
or individual making the release, the releasing party's address, the materials
or services supplied, the amount the contractor has paid for these supplies
or materials, and the address of homeowner's roof, and must be signed by
the releasing party."
Press for a strong written guarantee.
On asphalt composite shingle roofs, manufacturers' guarantees ranging from
20 years to 50 years are available. On built-up, modified bitumen, or single-ply
flat roofs, available manufacturer warranties range from less than 15 years
to more than 25 years. Roofers' guarantees of their workmanship usually
run from one to five years, but you may be able to get one for seven or
10 years or even longer.
If after signing a contract you wish you hadn't, move to cancel it.
If a roofer solicited your business at your home, you are free to cancel
until midnight of the third day after signing. Be sure to put your cancellation
letter in writing. It is sufficient to get it in the mail within the three-day
cancellation period, but send it via certified mail with return receipt,
FedEx, UPS, or some other way that gives you a record of the date you sent
it and its receipt by the contractor.
If possible, be at home some of the time when the work is being done.
If you are, you can catch early any misunderstandings about the materials
to be used, and you can spot any gross flaws in workmanship. (See examples
Leave a number where you can be reached.
Things will go more smoothly if your contractor can quickly reach you when
problems arise—such as problems with damaged sheathing or an unexpected
second layer of old shingles.
If possible, give the roofers access to a toilet, cold drinks, and other
Keep a file with your contract and specifications, any contract modifications,
invoices, canceled checks, and lien releases from subcontractors and materials
If you are not satisfied with your roofer's work, complain.
First negotiate directly with your roofing contractor. If that doesn't
work, complain to a complaint-handling agency.
You can save money by inspecting your roof regularly to spot incipient
problems. And you can save by making simple repairs yourself.
You won't save money, however, if you injure yourself or damage your roof
as you work on it. A few tips—
If your roof is steep or made of wood or slate, stay off it altogether.
There's just too much risk of a fall or damaging the roof by breaking shingles.
Even if it's safe to walk on, stay off your roof as much as possible. It
is easy to crack shingles or pull out nails, particularly if shingles are
warped. Much of the repair work done by roofers takes place shortly after
new TV antennas or satellite dishes have been installed or removed. Some
disreputable roofers in fact have turned the damages from careless roof-walking
to their advantage: they come out for a minor repair, or offer a free inspection,
and advise that a complete re-roofing job will soon be in order. By walking
on the roof roughly, they ensure that their prophecies are soon fulfilled.
If your roof is safe to walk on, use soft, rubber-soled shoes like tennis
shoes. These are best both for the roof and for your own safety.
Don't work on the roof in wet or windy weather. A wet roof or ladder can
be dangerously slippery, and a wind can easily knock you off balance. Be
sure you don't have wet grass or mud on your shoes.
Watch out not to put your weight on loose shingles or on weak spots that
you might put a foot through.
Be careful that neither you nor your ladder touches power lines.
Lift your ladder carefully, and position it properly. Put the bottom end
against the house; from the top end walk toward the house lifting the ladder
over your head until you reach the house and the ladder is upright; then
move the bottom end away from the house about one-fourth of the ladder's
length. So that you can more easily step off of and onto the ladder, the
top of the ladder should extend at least three feet above the edge of the
roof. Climb the ladder by stepping onto the center of each rung and using
both hands on the sides of the ladder. Tie off the ladder to the gutter
to reduce the risk of its being blown over.
When replacing damaged shingles, be sure that the newly installed shingles
lay flat over older ones. Also, try not to over-bend existing shingles
that do not need to be replaced. If you bend shingles too much, they'll
crack or split, and you will have to replace them also.
It's a good idea to inspect your roof at least annually and after a major
storm, even if you haven't noticed leaks.
If you have an unfinished attic or crawl space, you can do the most important
work from the inside. Look for any evidence that water has come into contact
with the rafters or sheathing. Poke at dark spots to see if they are rotten.
Be sure to look carefully around areas where vent pipes, chimneys, skylights,
or other elements pass through the roof. If you spot a hole in the roof,
jam a length of wire up through so you'll be able to find the hole from
If you have a finished attic, your task is more difficult. You can look
for signs of water damage on the ceiling and walls, but the location of
such damage may be far from the leak that causes it. Water often passes
through a leak and runs along rafters, only dropping off when it hits an
irregularity or obstruction. Problems you can't locate from the inside
have to be spotted by out-of-doors inspection.
To do an outdoor inspection, begin by checking gutters and the foundation
area for fallen shingles. Then look over the roof for missing or damaged
shingles (you may even be able to do this from the ground with binoculars).
If you've seen water damage on a ceiling or wall inside, try to locate
the point on the outside of the roof immediately above this damage and
then carefully work back and forth up the roof looking for the culprit
leak. Be sure to check that flashings around chimneys, vents, and other
protrusions have not developed holes or pulled loose.
In addition to spotting leaks and water damage, your inspection will reveal
whether the entire roof is due for replacement—
A roof of asphalt composite shingles (which may have either a fiberglass
or natural fiber base) needs to be replaced when it has simply eroded away;
first the granules on the surface disappear and then the shingles themselves
wear down. The first places to wear out are the surfaces below the decorative
cutouts or at the ends of shingles. When holes have eroded through the
shingles, abundant leaks are in store. Although asphalt composite shingle
roofs typically last more than 20 years, a roof's life might be less than
15 years or more than 50 years depending on how hot the roof gets, the
quality of the original roofing materials, and other factors. Even before
holes appear, your roof is on its last legs if shingles appear gray and
bloated and if a piece of shingle will crumble easily between your fingers.
Wood shake or shingle roofs may go bad from drying out and splitting or
warping. As shingles curl, they pull out nails and blow away. When you
begin to lose them, it may be time for a new roof. Wood shake or shingle
roofs occasionally last as long as 50 years, but one can fail much faster
if it is in a shady area where dampness, rather than drying out, is the
problem. In these instances, you may need to hire a roofer to treat your
roof with a preservative spray every three to five years. It is not uncommon
for a roof that cannot dry between rains to become mossy and rotted within
Tile or slate roofs can last indefinitely (though individual pieces may
have to be replaced).
Metal roofs need to be replaced when they become riddled with holes too
difficult to patch; but if maintained properly, they, like high-quality
slate and tile roofs, should last indefinitely.
Built-up roofs (composed of layers of hot bitumen and roofing felt, usually
topped with stone) need to be replaced when they become so dried up and
cracked in many places that leaks begin to occur. Other telltale signs
are blisters and places where the layers have delaminated. A four-ply built-up
roof should last 20 years or more.
Problems with single-ply and modified bitumen roofs are most likely to
occur at seams and around the drains. Look for separation at the seams
and bubbling or cratering of the membrane. Single-ply and modified bitumen
roofs should last 20 years or more.
If you discover a leak, you can easily apply a temporary remedy.
One option is an emergency patch using roofing cement, available from most
hardware stores. You just apply the compound generously to the roof surface,
even if it is still wet.
Another option, for a shingle roof, is to slide a piece of galvanized steel,
copper, or aluminum under the shingle above the location of a leak. The
metal should be large enough to cover the leaking area so that water will
be carried away from the leak.
There are also permanent repairs that some homeowners will be comfortable
If you find loose asphalt composite shingles, remove the loose nails, drive
in new nails, and cover the old holes and the heads of the new nails with
roofing cement. If asphalt composite shingles are merely warped, hold them
flat with a spot of roofing cement about the size of a quarter.
If it is necessary to replace a shingle, that is more difficult. Very carefully
lift the shingles that lie over the bad shingle, remove the nails holding
the bad shingle, remove the shingle, insert a new one, and replace the
If you have a small defect at a bubble in a built-up roof, you may be able
to cure it by slitting the bubble, cleaning out under the bubble with a
trowel or putty knife, sliding cement in under the bubble, pushing the
bubble down, driving in a row of nails on each side of the slit, and then
covering the area with a layer of cement, a layer of roofing felt nailed
around the edges, and a second layer of cement.
For a larger defect in a built-up roof, the process is more difficult.
You need to cut out a square of roofing material containing the defect.
Cut out the area one layer at a time, with each deeper square smaller than
the one above. Then cut new squares of felt to fit and put them in place,
starting with a layer of cement and alternating cement and felt until you
have replaced each layer. Drive nails around the perimeter of the top patch;
then apply another layer of cement, another larger piece of felt to cover
the whole area, and finally one more layer of cement.
Small holes in tin or galvanized steel roofs can be patched with a spot
of solder. Larger defective areas in these roofs can be patched with a
square of tin soldered around the edges or with a piece of canvas. If canvas
is used, just apply a coat of paint as adhesive, then the patch of canvas,
and then two or three more layers of paint.
For small holes in aluminum roofs, use aluminum-pigmented caulking compound.
Larger holes (an inch or more) can be patched with a piece of aluminum.
Coat the patch with the aluminum-pigmented caulking compound and hold it
in place with sheet metal screws that are coated in caulking.
Many cracks in flashing can be repaired, temporarily at least, with a layer
of roofing cement. Cement can also be used to fill small joints where flashing
has pulled loose from a chimney; simply scrape out the old mortar or cement,
put the flashing back in place, and fill the joint with cement.
Moss and Algae Damage
Moss or algae growth can be a problem for some roofs, particularly for
roofs of wood shingles. When moss or algae grows on a roof, it holds moisture
in, and can cause shingles to rot. Moss also can work down to the sheathing,
causing structural deterioration. You can remove moss or algae growth with
a commercial cleaner applied with a garden hose and/or by using a power
Some homeowners will feel comfortable doing more than simple repairs. You
may, for example, feel you can replace damaged sheathing and rafters and
you may wish to do your own re-roofing work. Many books and periodicals
that will help you in these more difficult jobs are available in libraries
Don't plan to take on an entire re-roofing job unless you're in excellent
physical shape, not afraid of heights, well-informed about building construction,
and not reluctant to do very hard, tedious work. A bundle of shingles weighs
about 70 pounds, and a typical roof might require more than 60 bundles,
each of which has to be lifted up. Also be wary of doing your own re-roofing
on a steeply pitched roof (more than five or six inches up for every 12
inches horizontal), a roof that requires new structural work underneath,
or one that has numerous dormers and other obstructions. Don't even consider
putting on a built-up roof and think twice about installing your own tile
roof; the tools and skills required for such roofs are beyond the reach
of most homeowners. Finally, remember that thousands of dollars worth of
damage can result if a rainstorm occurs when your house is without a roof.
Although you can probably provide for temporary covering to avoid or minimize
such damage, one advantage of professional roofers is that they almost
certainly will work faster than you can.
You'll be more careful in choosing and dealing with roofers if you're aware
of all that can go wrong.
Where water has leaked and sheathing has rotted, shingles are simply nailed
onto the rotten sheathing. The nails will pull out and shingles will come
Unseasoned materials are used to replace sheathing. The materials will
shrink, causing shingles to buckle.
At points where two different planes come together, flashing isn't put
into place or woven valleys of shingles aren't used. Leaks will occur at
Old flashings are reused although they are corroded, eroded, or punctured.
They will leak.
No counterflashing is used or what is used is not properly embedded in
the mortar or adequately attached. Counterflashing should be installed
over flashing materials to keep flashings dry; without it, water will leak
past the step flashing.
Valley flashings are too narrow. In a heavy downpour, water will wash up
under the shingles and turn back down under the flashings.
Flashings are not of heavy enough material. They will crack, puncture,
or erode away, causing leaks.
Instead of consisting of a series of short- to medium-length pieces stepped
over one another, flashings are long pieces, nailed at various places along
their length. With expansion and contraction caused by temperature change,
the metal will fatigue and split or nails will pull out.
Nails are too short. If nails are not long enough, they may pull loose.
Nails do not have barbed (or otherwise deformed) shanks. They may pull
Nailheads are too small. They may puncture the surface of the shingles,
hastening deterioration and leaks.
Nails are driven into knotholes or spaces between sheathing boards. They
will work their way up, forming lumps in shingles.
Too few nails are used. Shingles may come loose in wind or with repeated
Successive courses of shingles are not overlapped as required for the slope
of the roof. Water will back up under shingles or go through nail holes.
Cutouts or edges (end joints) of shingles on successive courses are not
adequately spaced or openings of one course are too near nail holes on
the course below. Water may weave from an opening on one course down through
a nearby opening or nail hole in the course below, causing leaks.
Too little space is allowed at joints of wood shakes or shingles. They
may swell and buckle in damp weather.
Shingles or slates are too heavy for the framing. Sagging of the roof may
damage shingles or create leaks where shingles do not lie properly.
Damaged or cracked shingles are used. They may leak.
In a new roof that is applied on top of an old one, tops of shingles are
not properly placed against butt ends of shingles on the roof. The roof's
surface will appear uneven.
The courses slant or the cutouts and edges are not properly aligned (they
are neither random nor regular). Appearance suffers.
Bulges and warps in shingles of a previous roof are not flattened. Appearance
suffers and leaks may occur.
Gutters sag, are loose, do not slope adequately, or are installed too low.
If gutters overflow or if water flowing from the roof overshoots gutters,
it may cause water to enter the house.
A built-up roof is applied over a metal roof. The metal will expand and
contract, tearing the felt.
Bituminous paint is used on a metal roof. It may form bubbles, allowing
the metal to rust underneath.
Contractors State License Board
P.O. Box 269116
Sacramento, CA 95826-9116
Santa Clara and Santa Cruz Counties
1112 S. Bascom Avenue
San Jose, CA 95128
All Other Bay Area Counties
1000 Broadway #625
Oakland, CA 94607