Roofing, Flashings and Chimneys
The primary function of the
roof system is to protect against and manage the
weather elements, particularly precipitation, thereby
protecting the interior and structural components of the
home. For the purposes of a home inspection, the roof
system consists primarily of the roof coverings,
flashings and chimney.
In addition to protecting the interior elements of the
home the roof components should also be designed, in
conjunction with the gutters and downspouts, to direct
rainwater and runoff away from the foundation area, to
help reduce the potential for soil erosion, compaction
and water entering the basement area.
Because of the important functions this system provides,
it's condition should be assessed regularly, and
maintenance provided when and wherever necessary.
There are two basic types of roof
construction, sloped (also called pitched) and flat.
Most sloped roofs are covered with individual pieces of
shingling material overlapped to prevent water
penetration. flat roofs are basically watertight
membranes that should have just enough slope to allow
water to run off. The slope of a roof can be a factor in
the life expectancy of the roofing material. The life
expectancy of a roof covering is also dependent upon the
type of material used, the quality of workmanship,
exposure to sun and wear from tree branches, snow/ice
and wind. For example, south and west roof faces have a
higher wear factor than north or east exposures, highly
reflective shingles tend to have a longer life
expectancy, and cement or slate roofs last much longer
than standard asphalt shingles (and cost a lot more!)
Asphalt shingling is the most common roofing material
used in residential construction in Canada. Other types
of covering for sloped roofs include asphalt roll
roofing, concrete or clay tiles, wood shakes and
shingles, and slate shingles. There are also fiberglass
shingles, metal shingles and metal sheet roofing
Flat roofs are built up with layers of molten asphalt
and felts, or covered with a membrane of modified
bitumin or asphalt base, or plastics or rubber. Most are
heat-sealed and some are glued.
The purpose of flashings is to prevent
the entry of water at areas on a roof where two
components join together or intersect (i.e. one roof to
another or a chimney thru a roof). Flashings can be
constructed of galvanized steel, tin, aluminum, copper,
lead or lengths of roll-roofing. The choice of flashing
material will be dependent upon the construction of the
roof and the material used for the roof covering.
Flashings will expand and contract, metal in particular,
with heat from the sun and air temperature changes. They
are also expected to move and stretch with typical
building shifts. The areas where flashings are required
are typically very vulnerable to water penetration.
There is a high risk of water leakage and wood decay
from a damaged, loose or poorly constructed flashing.
For all of the above reasons, regular monitoring and
routine maintenance of the flashing areas is essential
to preventing leaks.
The most common materials used in
chimney construction are masonry and steel. Masonry
chimneys can be brick, block or stone and are sometimes
stuccoed or parged. Chimneys often have more than one
flue. A flue is a separate and distinct channel for the
smoke on the inside of the chimney. In most cases, each
appliance within the house must have a separate flue. In
certain cases, two gas furnaces on the same floor within
a house can share a common flue, as can a gas furnace
and a gas hot water heater on the same level. Some wood
furnaces are designed to share a flue with an oil
furnace, if at the same floor level.
Some flues are unlined in that there is masonry exposed
on the inside of the flue. Unlined chimney flues are
most common in houses built before the Second World War.
These unlined masonry flues have performed reasonably
well for fireplaces and oil-fired furnaces, however most
have deteriorated beyond a safe condition. Gas
appliances require a suitable liner.
Flue can be lined with clay tiles or metal liner. For
more information about chimneys and chimney liners,
refer to the "Heating" section.
Skylights are windows installed into a
roof, where the ceiling is vaulted with the roof, or
where a well has been constructed thru the attic area,
to provide a passage from the ceiling to the roof
window. Ideally, skylights should be installed on curbs,
projecting at least 6 inches above the roof surface, in
order that proper flashings can be applied.
Some skylights are manufactured with built-in curb
and flashing assemblies. Sometimes skylights are
installed flush to the roof. This configuration almost
always leads to water penetration at the joint between
the skylight and the roofing material. Frequent
monitoring and regular maintenance of this joint are
essential to reducing the incidence of water
Evestroughs (gutters) and Downspouts (See "Exterior")
The component of roofs that is most
vulnerable to early deterioration is the area around the
flashings (chimneys, plumbing stacks, the intersection
of two or more roofs, skylights, etc.) It is not
uncommon for these areas to develop a leak well before
the rest of the roof material has aged significantly.
Also, because these areas are frequently made of metal
they can be more susceptible than the rest of the roof
coverings to damage from wind and expansion/contraction
from freeze/thaw cycles. So while flashings may appear
fine on the day of an inspection and the roof may be
relatively young in age, the flashings should be
monitored on a regular basis (at least semi-annually) to
detect any changes in condition that may indicate
maintenance or repair is necessary. Leaks left
unattended can cause serious damage to other parts of
the roof and structure.
Flat roof technology has been improving and some of the
newer methods are predicted to last longer with fewer
problems. However, as a generalization, flat roofs are
more vulnerable to leakage than sloped roofs. The
traditional method of covering flat roofs with built up
material does work, but it has a shorted life expectancy
than some of the newer materials and there is an
increased possibility of premature leakage. A primary
factor in the life expectancy of a built-up roof is the
workmanship of the installers. Built-up roofs with
excellent workmanship will last up to 15 years, while
the work of less skilled installers may develop problems
in 5 years or less. A flat roof that is past mid-life
may develop leaks fairly quickly. Because of this
behavior characteristic we recommend monitoring of flat
roofs to detect signs or symptoms that may indicate
If you are looking for Columbus Roofing, Flashings and Chimney services, please call us today at 614-263-8899 or complete our online request form.
Click Here For Your
Better Roofs Are Less Expensive
3 Things To Check When Hiring A Contractor
"Just a note to let you and your crew
know that they did a good job. I appreciate the way they kept me advised
of the job progress by using the door hanger. You need to be
commended for the effort you put into Customer Service – Something that
is hard to find nowadays"
Minerva Park, Ohio
Prefer to call us?
Call: (614) 263-8899
You Need To Know Before Hiring A Roofing Contractor"
Consumer's Guide that will help you avoid all
the hassles and headaches when you remodel your home.
Get One Today