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Roof ventilation in
Texas has not been a standard business practice with the
serious lack of over all quality control.
With the added costs to
properly install a venting system. Most Texans are not even
being offered the Shingle Vent Systems offered today. Did you
know that Manufacturer specifications these days specify using
adequate ventilation systems?
Proud Installers of
Shingle Ridge Vent Products: Cobra Rigid Vent II
New roofs or even in existing roofs, we highly
suggest the complete ridge vent systems and since 1984 have
never done a roof with out a complete ridge vent system.
After cutting out the peak, normally 3"
on each side from peak or atleast 1.5" min opening if
truss header is in place as seen above. Simply use 2.5 inch
roofing nails to install the 4ft pieces of rigid vent and
start the new shingle caps over the vent system. Giving you
the low profile appearance as seen below:
Completed 65sq GAF 30 year
Timberline Project, BY: Richard the Roofer Dec 2007 for Rev
Barron Nelson. Red Oak, Texas
Installation prices:
Normally on lower pitched roofs: 4/12-7/12
pitch (Walkable) rates vary between 15.00 per lf to 25.00 per
lf. The more linear footage needed would lower the over all
rate.
NON-Walkable roofs rates start at 25.00 per
linear foot supplied and installed
Soffit vents also installed 25.00 per vent or
complete removal and replacement of existing soffits and new
pre-drilled soffit installations. Per job
Turbine vents: 175.00 per vent
Power Fans (owner supplied) 150.00 electric
not included
Consider this:
Adding just 1 turbine vent gets you 1 sq ft of
vent on a standard 12x12 hole for 175.00
You could get almost 12lf of ridge vent for
the price of 1 turbine vent with a total of 6sq ft opening vs
the 1ft per turbine vent.
If you don't have soffit vents, we suggest
leaving the turbine vents until you can get the soffits upto
our standards. We believe these types of vents are NOT
waterproof and will allow rain into your attic if not set
properly to the pitch of your roof.
Contact us now for your free consultation:
214-244-5349
Ventilation
Systems and Requirements
FHA
minimum property standards state ventilation should be
one square foot of ventilation for each 150 square feet of
insulated attic surface area.
Added
Costs? No more than 15-20.00 per linear foot in most cases!
Savings?
Tremendous reduction in Air Conditioning, much longer
life cycle of the roof system. Prevention of damaging other
critical areas of the attic, such as attic insulations and or
framing due to trapped moisture
What
is attic ventilation? By AirVent
®
Intake
and Exhaust
"Ventilate" comes from the Latin word for
"to fan." Simply put, it's the action of
moving air. Out with the hot. In with the cool. And
that's exactly how ventilation works. It provides
conditions that allow air to flow. Every time stale,
overheated air in your home or attic is vented out and
fresh air is pulled in to replace it, you have what is
known as an "air exchange."
But
ventilation is much more than a simple breeze blowing
through your house. It's a process that provides a
steady, high volume of air movement. Think about it as
a system of components, all sized and positioned to
provide constant intake and exhaust of air.
Evaluate
your needs.
There
are a number of variables to consider when selecting
the most effective ventilation system for your home.
Before you make any decisions, go up into your attic
and take a look around. A sure sign of poor
ventilation is an unbearably hot attic in the summer.
Another thing to check is evidence of moisture, such
as mold, mildew, rusted nail heads, damp or compressed
insulation or wood rot.
Once
you've completed a general inspection of your attic,
look for ventilation systems already in place, such as
gable vents or roof louvers. Note the size and
locations of each. Do the same with intake vents,
including soffit and eave vents.
Finally,
make an estimate of the square footage of your attic.
Most are slightly larger than the size of one floor in
your home. You'll need this figure to make sure you
install adequate ventilation.
If your
roof pitch is 7/12 to 10/12, plan to add 20% to your
calculation for vent requirements; 30% for roof
pitches of 11/12 and steeper.
Vent
Requirements
According
to most building codes, you need one square foot of
vent area for each 150 square feet of attic floor
space. The minimum is one square foot for every 300
square feet of attic floor space if there is a vapor
retarder or the space is balanced between the ridge
and intake vents. A balanced ventilation system means
about 50 percent of the required ventilating area
should be provided by exhaust vents in the upper
portion of your attic with the remaining 50 percent
provided by intake vents.
Please
remember, building codes specify the minimum amount of
ventilation. You may want to increase the requirement
to ensure proper ventilation.
Common
Mistakes
Too
many times, homeowners install products that
short-circuit their ventilation system. When designing
a ventilation system, avoid these common pitfalls:
- Using
a combination of different types of exhaust vents,
like power vents with ridge vents. In this case,
competing vents pull air from each other instead
of from soffit vents.
- Underestimating
your ventilation needs. Remember that 15 roof
louvers or 5 turbine vents would be needed to
provide the same ventilation as 42 feet of ridge
vent on the same house.
- Installing
exhaust vents without adequate intake. An
effective balance of intake and exhaust must be
achieved to properly ventilate your home. The flow
of air in your attic is limited to the amount of
intake.
- Installing
a ridge vent that doesn't have an external baffle
to increase air flow and protect from weather
infiltration.
Types
of Vents
(Click
here
to learn about a variety of ventilation products from
Air Vent.)
Roofing
Ventilation Solutions by GAF: Why
Use a System - Attic Ventilation
Calculating
Your Ventilation Requirements
Example:
Calculating the number of lineal feet of Cobra®
Exhaust Vent needed for a 30’x 40’ attic: |
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Step
1
Step 2
Step 3
Step 4
Step
5
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Calculate
attic square footage
How: Multiply length of attic (in feet) times
width of attic (in feet)
30’ x
40’ = 1,200 square feet
Calculate NFA
(Net Free Area) needed for this attic by
using the “1 in 300” rule
How: Divide attic square footage by 300
1,200 sq.
ft. ÷ 300 = 4 square feet of NFA needed
Convert square feet of NFA to square inches
How: Multiply square feet of NFA by 144
4 sq. ft. x
144 = 576 square inches of NFA needed
Split the
amount of NFA needed equally between the
intake and the exhaust
How: Divide square inches of NFA needed by 2
576 sq. in.
÷ 2 = 288 square inches of NFA needed equally
for exhaust & intake
Calculate # of
lineal feet of Cobra® Exhaust Vent needed
How: Divide the square inches of NFA
needed at the ridge by the NFA of the Cobra®
Exhaust Vent
(Cobra® Exhaust Vent has 16.9 sq. inches of
NFA per lineal foot)
288 sq. in.
÷ 16.9 = 17 lineal feet
This attic
requires seventeen (17) lineal feet of Cobra®
Exhaust Vent to meet FHA minimum requirements.
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Intake
ventilation MUST be at least equal to exhaust
ventilation. To determine the number of intake
vents needed, select your vent on page 12, and
install enough vents so that their combined
NFA is at least 288 square inches.
Remember:
Always have a balanced ventilation
system. In no case should the amount of
exhaust ventilation exceed the amount of
intake
ventilation
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