Residential - Ventilation
Ventilation is the key to the longevity of your roof.
During the summer months, without proper venting, the attic space can
heat up enough to actually bake the shingle from the underside killing
the life of the roof. This is probably what started the old adage that:
"It doesn't matter if you get a 20 or 25 year shingle, you're lucky if
you get 14 or 15 years out of it." again, venting is key!
During the winter months venting is just as important.the concern now
is moisture. In winter, because the home is closed up tight do to the
cold outside, moister from day to day activities such as cooking
showering and perspiring are now trapped in the home and will collect
in the attic. This can cause mold and mildew to form in walls and dark
corners of closets.
So if you see where someone has put a plastic bag over their turbine
vent to keep it from spinning in the winter...wrong!
Now that brings us to what types of vents are available and which
one(s) should be used for your particular situation.
There are basically four types of vents presently being used; static
vents, turbine vents (whirly-bird), power vents and ridgevents.
One, is the static vent (an exhaust vent). This vent is best described
as a hole with a lid on top. To install it you must first cut a hole in
the side of the deck on the roof and then set it in, weaving the
shingles around it so that it is properly flashed. This vent is not
atheistically appealing and is always put on the back of the home so
that it is not seen from the front.
Two, is the turbine vent or whirly-bird (an exhaust vent). This vent is
applied in the same manner as the static vent. It is a mechanical vent
because it uses the wind to spin its top to try and draw out the air
from inside the attic. This vent is also placed on the back of the home
for the same reasons as the static vent, although, in order for it to
work properly, it must stick up over the ridge enough to collect wind
from all directions, thus making it visible from the front.
Third, is the power vent (an exhaust vent). Again it is applied in the
same manner as the two previous vents and also on the back of the home.
It is a mechanical/ electrical vent. A good one will be equipped with
not only the standard thermostatic control but also a humistatic
control. These vents are usually set to turn themselves on at 90
degrees in the summer using its thermostat and again in the winter when
the humistat detects moister. These vents are designed for various
drawing capabilities based on the square footage of the area to be
vented so choose a size that best suits your needs.
Fourth, is the ridgevent (an exhaust vent) this vent gets its name
because of the location to which it is installed. It is applied by
cutting about 1-1/2 inches of decking away from either side of the main
horizontal ridge beam leaving one continuous opening at the very top of
the roof. It is then closed over with the ridgevent system and them
camouflaged with the capping shingles to finish the job. It is
important to note several things about this vent:
It is esthetically appealing because it can barely be seen from either
the front or the back of the home and it also provides more ventilation
per square inch then either the static vent or the turbine vent while
comparatively costing less.
Because it works on the premise that hot air rises, it sits in the best
possible location of the roof...the very top.
It is also designed to work in harmony with the soffit vents. (intake
vents located underneath the overhang of the roof)
It works like this; as the hot air in the attic rises and escapes
through the ridgevent system at the very top of the roof, a draw is
caused pulling cooler air in through the soffit vents at the lower
level thus creating a continuous exchange of attic air.
Note: for homes that do not have a soffit system there is a vent called
a starter vent that is recommended to simulate a soffit