Rooftop Tips: Patch Or Replace:
Sir/Madame: The leak in your roof is too serious
to repair. I'm afraid you need a whole new roof.
But don't worry, I can put it on for you and
give you a really good deal to boot. Traditional
Sales Pitch.
The roofing professionals of the world have a
somewhat earned reputation of almost always
telling you that you need a new roof. They
almost never suggest patch repair because it
isn't very profitable.
But patching is very practical and can extend
considerably the life of many roofs and is
thought necessary to achieve the normal life
expectancy of most roofing systems. And it often
can be carried out by an energetic
do-it-yourselfer.
Assuming the roof was competently installed, it
has a predictable life expectancy. If the roof
is relatively young, it's a good bet that simple
patching will get it to its expected retirement
time.
Here's how you can determine what type of roof
you have and its approximate life expectancy:
Built-up, gravel and slag roofs are made from a
layer of marble chips, gravel or slag stuck in a
layer of tar and are usually relatively flat.
Life expectancy: at least 20 years.
Tin, terne and other metal roofs are made by
joining the edges of metal sheets together to
form a smooth surface. When the roof is very
flat the seams are soldered together. When there
is enough pitch or incline to readily run water
off the roof, the metal sheets often have their
edges turned up so they can be butted and bent
together to form standing seams. These seams run
the full length of the roof from front to back.
Metal roofs normally are painted but you will
find some coated with tar. Life expectancy: at
least 60 years with painting. Tar promotes rust
and will shorten the life of metal roofs.
Rolled mineral roofing looks like big lasagna
noodles laid side to side and sprinkled with
colored sand. Life expectancy: about 10 years.
Elastomeric or rubberoid roofing is a thick,
rubberized covering. Life expectancy: more than
10 years.
Asphalt shingles are used in the most common
type of roofing. Shingles come in many shapes,
sizes, textures and weights, with the heavier
weights lasting longest. Life expectancy: about
15 years and more.
Wood shingle and shake roofing is made from
small, thin rectangular splits (for cuts) of
cedar, redwood and cypress. You can buy long
panels which look like the smaller pieces but
are installed in larger sections. Life
expectancy: approx. 20 years.
Asbestos Cement Shingles look like thin
rectangular starched grey corduroy pieces. The
roof will frequently show differing colors
around flashing. Life expectancy: about 40
years.
Slate roofing is actually an abundance of
miniature blackboards overlaying each other. The
qualities range from S3 to S1 with life times
from 40 to 80 years. These figures are
approximate, but if your roof is considerably
younger than these ages and you have a leak, it
is very probable that simple patching will get
you back on track. At the very least, ask
someone qualified who does not have anything to
sell you to inspect your roof for you.
The location of the leak is critical: Almost all
roofing leaks occur at flashing points. Flashing
refers to those materials which join different
parts of the house to the roof. Flashings are
usually metal but can be asphalt composition as
well. They can rust through or split due to
expansion and contraction with the weather or
even pull out of position. You can usually check
them from the underside.
Take a strong flashlight into your attic and
sight anywhere two roof surfaces come together,
where plumbing pipes or attic fans open through
the roof, where a roof surface intersects a wall
and especially around masonry chimneys. Stains
or darker colored wood indicate a leak. It may
indicate an old leak so unless the ceilings
below are being damaged, return during a
cloudburst.
Other than flashing leaks:
Wind driven tree branches and sometimes heavy
winds themselves can lift up, damage, or even
tear off small or large sections of roofing
systems. Small areas are usually easily noticed
from the ground and should be quickly replaced.
Color matches are unlikely and this type of
repair is best left to professionals.
Shingles that appear to bulge up slightly may
have a roofing nail backing up and out of the
sheathing. Lift up the shingle, pull out the
nail and set a new nail beside the old hole. Use
plastic roofing cement to seal over the old nail
hole.
The wind will sometimes come from just the right
(or wrong) angle to cause a little leak. These
leaks are very difficult to detect but usually
indicate that a shingle is not well sealed down
and can occasionally be remedied by applying
roofing cement along the edges of the suspected
shingle. (Finding the right shingle usually
takes the patience of Job the wisdom of Solomon,
and the luck of all Ireland).
When it isn't the roofs fault:
If your roof only leaks when there is the
combination of a deep snow on the roof and very
cold weather, it probably isn't a roof leak.
This is usually ice damming and is treatable by
adding insulation and improving the ventilation
under the roofs' surface or blocking up air
bypasses from the living space of the house into
the attic. Don't ever block up the attic vents
in the wintertime attempting to save heat; this
can cause ice damming.
Finding a competent professional: Always ask the
following questions to determine the
qualifications of any roofing contractor:
Do you subcontract the installation? Companies
that specialize in sales may not be great
installers. The bigger companies like Sears and
Wards exercise a considerable amount of control
over the people they subcontract to. The price
is usually higher, but it's generally worth it.
Larger firms also give you a better shot at a
meaningful warranty.
Who, by name, will install the roofing?
How many roofing mechanics do you employ and how
many men will be on the crew?
How experienced are your workers?
When could you start and finish?
What local work have you done and how long have
you been in business under this name at your
present location? Go to the reference desk of
local libraries for back copies of the Yellow
Pages to double check. A sizable ad run
consistently in the yellow pages is a strong
sign of professional stability. Check for
complaints with the Better Business Bureau.
Also, beware of sales pitches based on
materials. Name brand materials don't vary much
in cost and generally account for no more than
30 percent of the cost of an installation.
Chimney flashings are at the top of the list of
roof leaks. More recent house construction has
seen roofers simply cement metal flashing to the
bricks of the chimneys. In a relatively few
years the cement dries out and the flashing
pulls away from the chimney. This can be quickly
reattached by daubing plastic roofing cement
(sold in small cans in hardware stores) behind
the flashing with a thin putty knife. Older
better flashings were tuckpointed into the
masonry joints but these also frequently leak
with the passage of considerably more time. A
repair that is somewhat unsightly but very often
effective is to simply smear plastic roofing
cement over the metal flashing where it curves
under the shingles.
The next most common flashing leakage is around
plumbing "back vent" pipes which protrude
through the roof. You will find them above baths
and kitchens and should examine the pipes as
well as the wood roof sheathing around them.
Sometimes the wood will not show a stain but a
vertical rust line streak may be visible on the
pipe in the attic. These leaks are almost always
associated with some paint or plaster damage
below, sometimes several stories below. The leak
can almost always be sealed by cementing around
the metal collar that surrounds the pipe out on
the roof. Rafter movement and the effects of
sunlight make this a chore to be done about
every 5 years.
The next most common flashing leak is probably
in valleys. This is where two roof surfaces come
together with the consequent channeling of a
great deal of water down through this
intersection. Top quality flashing here will
display sections of metal separating the two
sloping roof sections all the way up the valley.
Lesser quality flashing might see composition
roofing used in place of the metal or see the
shingles themselves "woven" together at the
valley. Metal or composition materials that have
buckled and split can be cemented easily. Valley
openings that are narrow or that don't widen as
they progress down the roof sometimes feed water
under the overlapping shingles. These edges can
frequently be cemented. The esthetics should be
considered prior to attempting this.
Split level or split entry houses almost always
have a low and a high roof. Expect trouble where
the low roof intersects with the wall of the
taller section of the house. If the higher roof
has an overhanging soffit above this area you
can usually rest easy. Leaks here often show
themselves in stairways and behind kitchen
cabinets. Cementing of the flashing can be done
but it is always unsightly and vulnerable hence
this one is best left to a professional.
Having them is almost a guarantee of a leak:
Contrary to popular opinion, skylights don't
have to leak. A properly flashed skylight will
be watertight for 20 years and more.
Unfortunately it often seems there isn't a
roofer in town who knows how to do it. Once
again, roofing cement is your bridge to longer
life but the permanent repair calls for the
flashing to be redone by a competent
professional roofer.
Dormers cut through two roof surfaces as on a
gambreled barn type roof are very frequent leak
points. These leaks will usually occur within
two years of the house being built and are
almost always due to lack of proper flashing at
the higher roof level. No patching will do. Bite
the bullet and hire a professional to install
metal flashing.