U.S. patent application number 13/021942 was filed with the patent office on 2011-08-18 for ventilated roof apparatus and method.
Invention is credited to John C. Henderson.
Application Number | 20110201266 13/021942 |
Document ID | / |
Family ID | 44369970 |
Filed Date | 2011-08-18 |
United States Patent
Application |
20110201266 |
Kind Code |
A1 |
Henderson; John C. |
August 18, 2011 |
Ventilated Roof Apparatus and Method
Abstract
In ventilating a roof, an eave vent and a ridge vent are
provided. The eave vent and ridge vent each is equipped with a
fabric filter. The fabric filter is not waterproof and is wettable
and hence self-cleaning. The permeability to air of the eave vent
fabric filter is less than that of the ridge vent fabric filter and
the resistance to air flow of the eave vent is greater than that of
the ridge vent. The attic space under the roof acts as a manifold,
distributing low pressure throughout the attic space.
Inventors: |
Henderson; John C.;
(Springfield, PA) |
Family ID: |
44369970 |
Appl. No.: |
13/021942 |
Filed: |
February 7, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61337855 |
Feb 12, 2010 |
|
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Current U.S.
Class: |
454/365 ; 52/198;
52/95 |
Current CPC
Class: |
F24F 7/02 20130101 |
Class at
Publication: |
454/365 ; 52/95;
52/198 |
International
Class: |
F24F 7/02 20060101
F24F007/02 |
Claims
1. An apparatus, the apparatus comprising: a. a roof deck, said
roof deck being located on a structure, said roof deck covering an
attic space, said roof deck being pitched, said roof deck having a
ridge and an eave; b. a ridge vent located proximal to said ridge,
said ridge vent defining a ridge vent opening, said ridge vent
opening being in communication with said attic space through said
roof deck; c. an eave vent, said eave vent being located at said
eave, said eave vent defining an eave vent opening, said eave vent
opening being in communication with said attic space through said
roof deck, said ridge vent defining a ridge vent resistance to an
air flow, said eave vent defining an eave vent resistance to said
air flow, said eave vent resistance to said air flow being greater
than said ridge vent resistance to said air flow.
2. The apparatus of claim 1 wherein said ridge vent and said eave
vent are composed of a corrugated plastic, said corrugated plastic
defining a plurality of channels, said plurality of channels of
said ridge vent defining said ridge vent opening, said plurality of
channels of said eave vent defining said eave vent opening.
3. The apparatus of claim 2, further comprising: a. a ridge vent
fabric filter, said ridge vent opening being disposed on an outside
of said ridge vent, said ridge vent fabric filter covering said
ridge vent opening, said ridge vent fabric filter having a ridge
vent fabric permeability to air; b. an eave vent fabric filter,
said eave vent opening being disposed on an outside of said eave
vent, said eave vent fabric filter covering said eave vent opening,
said eave vent fabric filter having an eave vent fabric
permeability to air, said eave vent permeability to air being less
than said ridge vent permeability to air.
4. The apparatus of claim 3 wherein said ridge vent fabric filter
is composed of a wettable fabric.
5. The apparatus of claim 4 wherein said ridge vent defining a
ridge vent top and a ridge vent bottom, said ridge vent fabric
filter extending from said ridge vent top to said ridge vent
bottom, said ridge vent fabric filter being secured to said ridge
vent top and to said ridge vent bottom by a one of an adhesive bond
and a thermal weld, said eave vent defining an eave vent top and an
eave vent bottom, said eave vent fabric filter extending from said
eave vent top to said eave vent bottom, said eave vent fabric
filter being secured to said eave vent top and to said eave vent
bottom by a one of said adhesive bond and said thermal weld.
6. The apparatus of claim 5 wherein said eave vent opening is
composed of a first plurality of layers of said corrugated plastic,
said eave vent defining an eave vent support, said eave vent
support being composed of a second plurality of layers of said
corrugated plastic, said first plurality being greater than said
second plurality, said corrugated plastic of said eave vent support
defining a plurality of said channels, said eave vent opening being
in communication with said attic space through said channels
defined by said eave vent support.
7. An eave vent apparatus, the eave vent apparatus comprising: a
corrugated plastic, said corrugated plastic defining a plurality of
channels, said plurality of channels defining an eave vent intake
opening, said eave vent having a bottom side, said bottom side of
said eave vent opening defining an eave vent discharge opening,
said eave vent intake opening being in communication with said eave
vent discharge opening, said eave vent being configured so that
said plurality of channels defining said eave vent intake opening
are in communication with an attic space when said eave vent is
mounted to a top side of a roof deck having a ridge and an eave and
said eave vent discharge opening is in communication with a roof
deck eave vent opening proximal to said eave, said eave vent having
an eave vent resistance to air flow, said eave vent resistance to
air flow being selected so that said eave vent resistance to said
air flow is greater than a ridge vent resistance to said air flow
when said eave vent is mounted in communication with said roof deck
eave vent opening and said ridge vent is mounted in communication
with a roof deck ridge opening proximal to said ridge.
8. The apparatus of claim 7, the apparatus further comprising: A
soffit fabric filter, said eave vent opening being disposed on an
outside of said eave vent, said eave vent fabric filter covering
said eave vent opening, said eave vent fabric filter having an eave
vent fabric permeability to air, said eave vent permeability to air
being less than a permeability to air of a ridge vent fabric filter
when said eave vent is mounted in communication with said roof deck
eave vent opening and said ridge vent is mounted in communication
with said roof deck ridge opening, and said ridge vent has a
discharge opening covered by said ridge vent fabric filter.
9. The apparatus of claim 8 wherein said eave vent fabric filter is
composed of a wettable fabric.
10. A ridge vent apparatus, the ridge vent apparatus comprising: a
corrugated plastic, said corrugated plastic defining a plurality of
channels, said plurality of channels defining a ridge vent
discharge opening, the ridge vent apparatus having a bottom side,
said bottom side of the ridge vent apparatus defining a ridge vent
intake opening, said ridge vent intake opening being in
communication with said ridge vent discharge opening, said ridge
vent intake opening being in communication with an attic space when
said ridge vent is mounted to a ridge of a roof deck and said ridge
vent intake opening is in communication with a roof deck ridge
opening in said roof deck, said ridge vent having a ridge vent
resistance to air flow, said ridge vent resistance to air flow
being selected so that said ridge vent resistance to said air flow
is less than an eave vent resistance to said air flow when said
ridge vent is mounted to said roof ridge and said eave vent is
mounted in communication with said attic space proximal to an eave
of said roof deck.
11. The apparatus of claim 10, the apparatus further comprising: A
ridge vent fabric filter, said ridge vent discharge opening being
disposed on an outside of the ridge vent apparatus, said ridge vent
fabric filter covering said ridge vent discharge opening, said
ridge vent fabric filter having a ridge vent fabric permeability to
air, said ridge vent permeability to air being greater than a
permeability to air of an eave vent fabric filter when said ridge
vent is mounted to said ridge of said roof deck, and said eave vent
is mounted in communication with said attic space proximal to said
eave, and said eave vent has an intake opening covered by said eave
vent fabric filter.
12. The apparatus of claim 11 wherein said ridge vent fabric filter
is composed of a wettable fabric.
13. A method for ventilating a roof, the method comprising: a.
providing a ridge vent, said ridge vent being composed of a
corrugated plastic, said corrugations defining a plurality of ridge
vent channels, said plurality of ridge vent channels defining a
ridge vent discharge opening, said bottom of said ridge vent
defining a ridge vent intake opening, said ridge vent having a
resistance to air flow from said ridge vent intake opening to said
ridge vent discharge opening; b. installing said ridge vent, the
roof defining a roof deck having a ridge and an eave and defining
an attic space, said roof defining a roof deck ridge opening
proximal to said ridge, said roof deck ridge opening communicating
through said roof deck, said ridge vent being installed so that
said ridge vent intake opening is located in communication with
said attic space through said roof deck ridge opening; c. providing
an eave vent, said eave vent being composed of said corrugated
plastic, said corrugated plastic defining a plurality of eave vent
channels, said plurality of eave vent channels defining an eave
vent intake opening, said eave vent having a bottom side, said eave
vent bottom side defining an eave vent discharge opening, said eave
vent intake opening being in communication with said eave vent
discharge opening, said eave vent having an eave vent resistance to
air flow from said eave vent intake opening to said eave vent
discharge opening, said eave vent resistance to air flow being
greater than said ridge vent resistance to air flow; and d.
installing said eave vent proximal to said eave of said roof deck,
said eave vent discharge opening being in communication with said
attic space.
14. The method of claim 13 wherein said ridge vent includes a ridge
vent fabric filter, said ridge vent fabric filter being configured
to cover an outside of said ridge vent discharge opening, said
ridge vent fabric filter having a ridge vent permeability to air,
said eave vent including an eave vent fabric filter, said eave vent
fabric filter being configured to cover an outside of said eave
vent intake opening, said eave vent fabric filter having an eave
vent permeability to air, said ridge vent permeability to air being
greater than said eave vent permeability to air.
15. The method of claim 14 wherein said ridge vent has a ridge vent
top side, said ridge vent fabric filter extending from said ridge
vent top side to said ridge vent bottom side, said ridge vent
fabric filter being attached to said ridge vent top side and to
said ridge vent bottom side by a one of an adhesive bond and a
thermal weld, and wherein said eave vent has an eave vent top side,
said eave vent fabric filter extending from said eave vent top side
to said eave vent bottom side, said eave vent fabric filter being
attached to said eave vent top side and to said eave vent bottom
side by said one of said adhesive bond and said thermal weld.
16. The method of claim 15 wherein said ridge vent fabric filter
and said eave vent fabric filter are composed of a wettable
fabric.
17. The method of claim 16 wherein said ridge and said eave of said
roof each has a length, said ridge vent has a length and said eave
vent has a length, said length of said ridge vent is selected to
occupy substantially all of said length of said ridge, said length
of said eave vent is selected to occupy substantially all of said
length of said eave.
Description
I. RELATED APPLICATIONS
[0001] This application is related to and claims priority from
provisional application No. 61/337,855 filed Feb. 12, 2010 by the
inventor named herein.
II. BACKGROUND OF THE INVENTION
[0002] A. Field of the Invention
[0003] The Invention is an apparatus for ventilating a roof, a roof
ventilated using the apparatus of the invention and a method of
ventilating a roof using the apparatus.
[0004] B. Statement of the Related Art
[0005] Moisture trapped in an attic or other space underneath the
pitched roof of a structure can damage the roof, can damage the
remainder of the structure and can promote growth of mold within
the attic. To avoid these effects, the space underneath the roof
must be ventilated.
[0006] As used in this document, the term `attic` refers to an
attic and also refers to any other air space under a roof, such as
the space between a ceiling or insulation and a roof deck of a
structure equipped with a cathedral ceiling.
[0007] During daylight hours, the sun shining on the roof warms the
roof deck, causing the roof deck to be warmer than the ambient air.
The warm roof deck warms the air within the attic. During cold
weather, heat within the inhabited space of the structure will leak
into the attic space, which also warms the air in the attic space.
The warm air within the attic space expands, becomes buoyant, and
tends to rise. Because the roof is pitched, the warm air rises
toward the ridge of the roof. The warm air can be released from the
ridge by a ridge vent.
[0008] Warmed air escaping from the vent will place the attic space
at a lower air pressure than the ambient pressure outside the
attic. For effective ventilation, eave vents are provided to allow
make-up ambient air to enter the area under the roof. If any
portion of the roof is starved for ventilation air, then the lack
of air flow through the air-starved attic space may allow the evils
of inadequate ventilation to occur.
[0009] A roof equipped with eave and ridge vents acts as a large,
low-pressure air pump, pumping air out through the ridge vent and
in through the eave vents. The power input to the roof air pump
system is heat energy generated either by sunlight shining on the
roof deck or by heat leaking into the attic from the heated living
space of the structure.
[0010] The ridge and eave vents must provide both an avenue for
escape and entry of the air and also must prevent the entry of
moisture in the form of rain or snow into the attic space. To that
end, a ridge vent or an eave vent may feature a fabric filter. The
prior art fabric filter generally is selected to be water proof and
to prevent rain or snow from entering the vent while allowing air
to pass through the fabric.
[0011] Because the flow of air through the attic is generally from
the eave vent to the ridge vent, dust or dirt in the air moving
through the attic can be trapped on the side of the fabric filter
of the ridge vent that is toward the attic. The result is that the
ridge vent can become blinded over time.
[0012] Blinding of the fabric filter is less of an issue for an
eave vent, since dust and dirt will tend to collect on the side of
the fabric filter that is toward the outside of the structure.
Provided that the fabric filter is located so as to expose the
fabric filter to the weather, rain water may wash the dust and dirt
from the fabric filter of the eave vent, preventing the fabric
filter from becoming blinded.
[0013] The present invention is not taught by the prior art.
III. SUMMARY OF THE INVENTION
[0014] The invention is an apparatus for ventilating an attic or
other area under a roof. The invention also is a roof ventilated
using the apparatus and a method of ventilating a roof. The
apparatus is a ridge vent, an eave vent, and a combination of the
ridge and eave vents. The ridge vent may be a two-sided ridge
vent.
[0015] As used in this document, the term `eave` generally means
the horizontal roof edge of a pitched roof. The `eave` is generally
the lowest location on a pitched roof deck. As used in this
document, the term `eave vent` includes a vent in a soffit located
below a roof deck and also includes a top vent communicating
through the top side of the roof deck from above. The `eave vent`
generally is located proximal to the eave, but in the case of the
top vent may be located anywhere on the roof below the ridge
vent.
[0016] As used in this document, the term `ridge` means the
locations on a pitched roof defined by intersecting planes of the
roof deck and that define an included angle of less than 180
degrees. The `ridge` generally is the highest location on the roof,
unless the roof utilizes the hip roof design, in which event the
`ridge` may slope from the peak of the roof to the eave. As used in
this document, a `ridge vent` is located proximal to the ridge,
including the sloping ridges of a hip roof.
[0017] A primary goal of any roof ventilation system is to provide
ventilation to the attic or other entire area under the roof. As
noted above, if flow paths through a portion of an attic do not
exist, that portion of the attic will not be ventilated. If flow
paths exist, but if other flow paths present inadequate resistance
to air flow, the air will take the flow path of low resistance. The
remainder of the roof that has a higher resistance to air flow will
be starved for ventilation air and will suffer the evils associated
with inadequate ventilation, as described above.
[0018] The apparatus, method and roof of the invention achieve more
even ventilation of the attic space by adjusting the air flow
resistance of the eave and ridge vents. The resistance to air flow
is adjusted so that the resistance to air flow presented by the sum
of the ridge vents is less than the resistance to air flow
presented by the sum of the eave vents supplying the ridge vents.
The entire attic space therefore operates at a negative pressure
when the air in the attic is warmed, which negative pressure no one
region of the eave vents can relieve. The volume of the attic
therefore acts as a large manifold, conveying that negative air
pressure to every corner of the attic.
[0019] Eave vents are provided in all areas of the roof, providing
paths for ambient air to enter the attic. The resistance to air
flow of the eave vents is selected to allow entry of ventilation
air but not to allow so much air to enter that the negative
pressure under the roof is relieved at any location. The resistance
to air flow of the eave vents is selected to be substantially
greater than the resistance to air flow of the ridge vent because,
for a pitched roof, the length of the eaves for a roof generally is
considerably greater than the length of the ridge. The length of
the eave vents therefore generally is much greater than the ridge
vents.
[0020] Both the ridge vent and the eave vent are composed of a
corrugated plastic. The corrugations of the plastic define multiple
elongated channels through which air passes.
[0021] The eave vent features an eave vent intake opening defined
by the open ends of the multiple elongated channels that are
exposed to the air outside the roof. The eave vent also features an
eave vent discharge opening exposed to the air in the attic through
a roof deck vent opening proximal to the eave.
[0022] The ridge vent features a ridge vent discharge opening that
is exposed to the air outside the attic and defined by the open
ends of the multiple elongated channels. The ridge vent also
features a ridge vent intake opening communicating through the roof
deck at a roof deck ridge opening proximal to the ridge. The
discharge opening of the ridge vent and the intake opening of the
eave vent are defined by the open ends of the multiple elongated
channels defined by the corrugated plastic.
[0023] A fabric filter covers the discharge opening of the ridge
vent and the intake opening of the eave vent. The fabric filter is
composed of a fabric that wraps about each of the soffit and the
ridge vent and is attached to both the top and the bottom of the
soffit and of the ridge vent. Any suitable attachment means may be
utilized, such as an adhesive bond or a thermal weld.
[0024] The fabric of the fabric filter is selected to allow water
to pass through the fabric. The fabric is wettable and allows
moisture to wick through the fabric and to wet both sides of the
fabric, while preventing substantially all droplets of water from
traveling through the fabric. Water that has passed through the
fabric moves by gravity from the top to the bottom of the fabric.
In so doing, the water entrains and carries off dust collected on
both the inside and outside surfaces of the fabric. The fabric
therefore allows the water to wash the dust from both the inside
and the outside surfaces of the fabric, preventing blinding of the
fabric filter.
[0025] Location of the fabric filter on the outside of the channels
defined by the corrugated plastic prevents water that passes
through the fabric from entering the attic space. Because the
fabric filter is located at the outside end of the elongated
channels defined by the corrugated plastic, any water passing
through the fabric must travel the length of the elongated channels
to reach the attic. Because the roof is pitched and because the
elongated channels also are pitched to conform to the roof deck,
that water is required to run up hill. Water penetrating the
wettable fabric therefore does not enter the attic.
[0026] Attachment of the fabric filter to both the top side and the
bottom side of the ridge vent or eave vent allows convenient
handling and installation of the fabric filter. Installation of the
ridge or eave vent involves nailing through the vent from the top
side to the bottom side. Some of the nails penetrate the fabric
that is wrapped about the top side and the bottom side of the vent,
mechanically securing the two ends of the fabric to the roof. The
mechanical connection of the fabric to the roof allows the fabric
to withstand high winds without failure.
[0027] The resistance to air flow of the ridge vent and the eave
vent is determined by the friction of air passing through the
channels and by the air permeability of the fabric filter for each
of the eave vent and the ridge vent. The dimensions of the eave
vent and the ridge vent, and hence the friction of the air passing
through the channels, are constrained by practical and aesthetic
considerations. Those considerations include that the channels
cannot be so large as to allow rain or snow to enter the attic
space and cannot be so small as to easily blocked, as by leaves and
debris. The aesthetic considerations include the appearance of the
vent on the roof. The dimensions of the channels therefore do not
allow extensive adjustment of the resistance to air flow of the
vents.
[0028] Nonetheless, resistance to air flow can be readily adjusted
by selecting a fabric filter having an appropriate permeability to
air; namely, the resistance to air flow per unit area of the
fabric. Selecting a fabric filter for the eave vent that has a low
permeability relative to that of the ridge vent allows the air
pressure within the attic to remain adequately low so that the
attic acts as a manifold, drawing ventilation air through all of
the eave vents and while providing adequate ventilation to the
entire attic space.
[0029] The apparatus, method and roof of the invention provide that
the fabric filter of the eave vents is selected so that the
permeability of the soffit filter fabric is less than the
permeability of the ridge vent filter fabric.
[0030] The apparatus, method and roof of the invention is
particularly useful for ventilating roofs that previously have been
difficult to ventilate without excess water penetration, such as
hip roofs.
IV. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a schematic cross section of a ventilated
roof.
[0032] FIG. 2 is a schematic representation of air flow through the
roof.
[0033] FIG. 3 is a cross section of a ridge vent in place on the
roof deck.
[0034] FIG. 4 is a perspective view of the ridge vent of FIG.
3.
[0035] FIG. 5 is a cross section of an eave vent in place on a roof
deck.
[0036] FIG. 6 is a perspective view of the eave vent of FIG. 5.
[0037] FIG. 7 is a perspective view of a roof deck.
[0038] FIG. 8 is a perspective view of the roof deck with an eave
vent in place.
[0039] FIG. 9 is a perspective view of the roof deck in the process
of installing shingles and the ridge vent.
[0040] FIG. 10 is a perspective view of the completed roof.
V. DESCRIPTION OF AN EMBODIMENT
[0041] The invention is an apparatus and method for ventilating an
attic space or other area under a roof. As illustrated by FIGS. 1
and 7 through 10, a roof deck 2 covers a structure 4. The structure
4 features an attic space 6 beneath the roof deck 2. As used in
this document, the term `attic space` also includes any area under
a roof, such as the space between the ceiling and a roof deck 2 of
a room having a cathedral ceiling. The roof deck 2 is pitched as
illustrated by FIGS. 1 and 7 through 10, meaning that the roof deck
2 defines an adequate angle with the horizontal to allow the use of
shingles 12. The roof deck 2 is composed of any suitable planar
material, such as plywood or metal sheets. The roof deck 2 defines
a ridge 8 at its highest location and an eave 10 at a location
lower than the ridge 8.
[0042] As illustrated by FIGS. 1, 3, 4, 9 and 10, the roof includes
a ridge vent 14 covering a roof deck ridge vent opening 16 located
at the ridge 8 of the roof deck 2. The roof also includes an eave
vent 18 covering a roof deck eave vent opening 20 located proximal
to the eave 10. The eave vent 18 and roof deck eave vent opening 20
may be at any location on the roof deck 2 below the elevation of
the ridge 8 and ridge vent 14.
[0043] The eave vents 18 illustrated by the drawings are of the top
vent type and communicate with the attic space 6 through the eave
vent opening 20 from above the roof deck 2. This description of an
embodiment applies equally to an eave vent 18 of the soffit vent
type that communicates with the attic space 6 through the soffit
from below the roof deck 2.
[0044] As shown by FIG. 1, air 22 within the attic space 6 is
warmed by the sun shining on the roof deck 2 or by heat from the
inhabited space of the structure 4. The air 22 expands due to the
increased temperature. The warmed air 22 is more buoyant than other
air 22 within the attic space 6 and rises within the attic space 6
until the air reaches the ridge 8. The warmed air 22 flows through
the ridge vent opening 16 and through the ridge vent 14. Make-up
air 22 flows from outside the attic space 6 through the eave vent
18 and through the roof deck eave vent opening 20 into the attic
space 6. The ventilated roof, including the eave vent 18, the eave
vent opening 20, the attic space 6, the roof deck 2, the ridge vent
opening 16 and the ridge vent 14 comprises a heat-powered air pump,
pumping air 22 out through the ridge vent 14 and in through the
eave vent 18.
[0045] FIG. 2 is a schematic diagram illustrates the air pressure
and flow relationships of the ventilated roof. Heated air 22 flows
out of the attic space 6 through ridge vent 14 due to the buoyancy
of the heated air 22. The departure of the heated air 22 through
the ridge vent 14 reduces the air pressure within the attic space
6. The reduced air pressure within the attic space 6 causes cool
make-up air 22 to flow through the eave vents 18 due to the higher
air pressure outside the attic space 6. The cool air 22 is warmed
within the attic space 6, becomes buoyant and rises to the ridge
vent 14, repeating the process.
[0046] All areas of the roof are equipped with eave vents 18, as
indicated by the four schematic eave vents 18 of FIG. 2. The flow
of air 22 at any one location on an eave vent 18 is determined by
the air pressure differential across the eave vent 18 and coupled
with the resistance to air flow presented by the eave vent 18. The
air pressure differential across a portion of an eave vent 18 is
determined by factors that include the buoyancy of the air 22
exiting the ridge vent 14, whether the portion of the roof deck 2
above the eave vent is subject to direct sunlight, the resistance
of all of the other portions of eave vent and the length of the
flow path from the eave vent 18 to the ridge vent 14.
[0047] Air 22 flowing into the attic space 6 will follow the path
of least resistance. If one (or more) of the eave vents 18 presents
an adequately low resistance to air flow coupled with a short flow
path while other eave vents 18 present a higher resistance to air
flow coupled with a longer flow path, the portions of the eave
vents 18 with very low resistance and hence a relatively high air
flow may relieve the pressure difference between the inside and
outside of the attic space 6. The portions of the attic space 6
served by the eave vent 18 having a higher resistance and a longer
flow path then will see little, if any, airflow. Portions of the
attic space 6 then are starved of ventilation air 22 and may suffer
from all of the ill effects of inadequate ventilation.
[0048] The airflow can be more evenly distributed among the eave
vents 18, assuring more even ventilation of all areas of the roof,
if the resistance to airflow of each eave vent 18 is adequately
high so that the attic space 6 acts as a manifold, distributing the
relatively low pressure to all areas of the attic space 6.
[0049] FIGS. 3 through 6 illustrate construction of the ridge vent
14 and the eave vent 18 to achieve more even distribution of
ventilation air 22 within the attic space 6. FIG. 3 is a cross
section of a ridge vent 14 installed on a roof deck 2. Roof deck 2
defines a pitched roof and is clad with shingles 12. Ridge vent 14
is composed of corrugated plastic panels 28. Each corrugated
plastic panel 28 comprises two planar plastic layers with a
corrugated plastic layer in between, similar in appearance to
familiar corrugated cardboard. The corrugated plastic 28 panels
define a plurality of channels 30. The plurality of channels
communicate between a ridge vent opening 24, also referred to
herein as the `ridge vent discharge opening 24,` that is in contact
with air 22 outside of the ridge vent 14 and a ridge vent intake
opening 31 on the underside 32 of the ridge vent 14. The ridge vent
intake opening 31 is in communication with the roof deck ridge vent
opening 16, which is in communication with the air 22 within the
attic space 6.
[0050] The ridge vent opening 24 is equipped with a ridge vent
fabric filter 34 that covers the ridge vent opening 24. As shown by
the detail cutaway drawing of FIG. 4, the ridge vent fabric filter
34 is wrapped about the top 36 and the bottom 38 of the ridge vent
14 and secured to the top 36 and bottom 38 of the ridge vent 14 by
an adhesive bond or by thermal welding.
[0051] As shown by FIG. 3, wrapping of the fabric filter 34 about
the top 36 and bottom 38 of the ridge vent 14 allows the fabric
filter 34 to be secured to ridge vent 14 and to the roof deck 2 by
nails 40 when the ridge vent 14 and shingles 12 are installed.
[0052] The size of ridge vent opening 24, and hence the area of the
ridge vent available to allow heated air 22 to escape, is
constrained by aesthetic considerations of the appearance of the
finished roof. Three layers of corrugated plastic panels 28,
totaling about three quarters of an inch in thickness, has proven
acceptable in practice.
[0053] The construction of the eave vent 18 is illustrated by FIGS.
5 and 6. The eave vent 18 also is composed of corrugated plastic
panels 28 defining a plurality of eave vent channels 30. The
channels communicate between an eave vent opening 26, also referred
to herein as the `eave vent intake opening 26,` and an eave vent
discharge opening 50 on the eave vent bottom 48. The eave vent
opening 26 is on the outside of the eave vent and in contact with
air 22 outside the attic space 6. The eave vent discharge opening
50 is in communication with a roof deck eave vent opening 20 that
communicates through the roof deck 2 to the attic space 6. The
thickness of the eave vent opening 26 is driven in part by
aesthetic considerations and in part by resistance to moisture
penetration. Three layers of corrugated plastic panels 28, totaling
about three quarters of an inch in thickness, have proven suitable
in practice.
[0054] The eave vent 18 is wedge-shaped. To maintain the
wedge-shape while allowing ventilation air 22 to move through the
eave vent 18, an eave vent support 42 intermediate between the eave
vent opening 26 and the roof deck eave vent opening 20 is provided.
The eave vent support 42 is composed of a second plurality of
layers of corrugated plastic panels 28. The number of panels 28
making up the eave vent support 42 is less than the number of
panels making up the eave vent opening 26 to allow the eave vent 18
to be wedge-shaped when installed on a roof deck 2. A thickness of
two corrugated plastic panels 28 have proven suitable in practice
for the eave vent support 42.
[0055] An eave vent fabric filter 44 covers the eave vent opening
26. The eave vent filter fabric 44 is wrapped about the eave vent
top 46 and the eave vent bottom 48. The wrapping of the eave vent
fabric filter 44 about the top 46 and bottom 48 provide that nails
40 will secure the filter fabric 44 to the eave vent 18 and the
eave vent 18 to the roof deck 2 when the eave vent 18 is
installed.
[0056] The ridge vent fabric filter 34 and the eave vent fabric
filter 44 each has a permeability to air flow. The resistance of
the ridge vent 14 and the eave vent 18 to the passage of air 22 is
a function of the size (thickness and length) of the ridge vent
opening 24, the friction of the air 22 moving through the channels
30 of the ridge 14 and soffit 18 vents and the permeability to air
flow of the ridge vent fabric filter 34 and the permeability to air
flow of the eave vent fabric filter 44. The less permeable the
fabric filters 34, 44, the higher the resistance to air flow and
the less air 22 that can flow through the vent 14, 18 for a given
air pressure differential.
[0057] The resistances to air flow of the ridge vent 14 and the
eave vent 18 therefore can be selected by selecting appropriate
fabric filters 34, 44. The fabric filters 34, 44 are selected so
that the permeability of the eave vent fabric filter 44 is less
than the permeability of the ridge vent fabric filter 34. For ridge
and eave vents 14, 18 having approximately the same total area for
the eave vent opening 26 and the ridge vent opening 24, selecting
fabric filters 34, 44 when the permeability of the eave vent fabric
filter 44 is less than that of the ridge vent fabric filter 24
provides that the entire attic space 6 is maintained at a reduced
air pressure when the ventilation system is in operation to
ventilate the roof and provides that no portion of the attic space
6 is starved for ventilation air. In short, the entire attic space
6 acts as a manifold and distributes the reduced air pressure to
all of the eave vents 18.
[0058] The fabric filter 34, 44 is selected to be wettable for the
purposes of washing accumulated dust from otherwise inaccessible
fabric filter 34, 44 surfaces. The wettable fabric selected for the
fabric filters 34, 44 is not waterproof and allows water from rain
or snow to move through the fabric filters 34, 44 from the outside
of the ridge and eave vent openings 24, 26. The water runs down the
inside surfaces of the fabric filters 34, 44 due to gravity,
rinsing accumulated dust from the fabric filters 34, 44. The use of
a non-waterproof, wettable fabric for fabric filters 34, 44 allows
both sides of the fabric filters 34, 44 to be cleaned by water from
rain or snow. The water is prevented from entering the attic space
6 or from otherwise entering the structure 4 by the uphill journey
through the multiple channels 30 that the water would have to
travel to reach the attic space 6 (see FIGS. 3 and 6).
[0059] The wettable fabric that has proven successful in practice
is Colback.RTM. TD series by Colbond, Inc., P.O. Box 1057, Enka,
N.C. 28728. Colbond, Inc is a division of Low & Bonar PLC, a
publicly traded UK corporation domiciled in Scotland. The
Colback.RTM. fabric is a spunlaid, nonwoven fabric made from
bicomponent filaments having a polyester core and a nylon 6 skin.
The fibers are thermally bonded to form the fabric. The
permeability to air of the fabric varies as does the weight of the
fabric. The applicant believes that a fabric having a weight of 100
grams per square meter is suitable for the fabric filter 44
covering the eave vent opening 26. The applicant believes that a
fabric having a weight of 30 to 50 grams per square meter is
suitable for the fabric filter 34 covering the ridge vent opening
24. The fabric is selected to be black or dark gray in color for
maximum heat absorption and to aesthetically blend in with the
appearance of the roof.
[0060] FIGS. 7 through 10 illustrate installation of the apparatus
of the invention. FIG. 7 is a roof deck 2 of a structure 4, such as
a building. The roof deck 2 has a top side 52 and includes an eave
10 and a ridge 8. The roof deck also includes a roof deck eave vent
opening 20 proximal to the eave 10 and a roof deck ridge opening 16
proximal to the ridge 8. The roof deck 2 is pitched.
[0061] FIG. 8 illustrates location of the eave vent 18 on the roof
deck 2. The eave vent 18 is located proximal to the eave 10 and is
located so that the eave vent discharge opening 50 is in
communication with the roof deck eave vent opening 20. An end cap
54 tapers the eave vent 18 to the roof deck 2 and prevents breakage
of shingles 12.
[0062] FIG. 9 illustrates the relative location of the eave vent
18, shingles 12, roof deck 2 and ridge vent 14. In FIG. 9, the eave
vent 18, shingles 12 and ridge vent 14 are in the process of being
installed. The shingles 12 cover the eave vent 18 and end cap 54.
The ridge vent 14 overlays the top course of shingles 12 and covers
the roof deck ridge vent opening 16 so that the ridge vent opening
24 on the outside of the ridge vent 14 is in communication through
the ridge vent 14 to the roof deck ridge vent opening 16. The ridge
vent 14 is two-sided, in that ridge vent openings 24 appear on both
sides of the ridge 8. Ridge vent fabric filter 34 wraps about the
ridge vent 14 and covers ridge vent opening 24.
[0063] FIG. 10 illustrates the roof with eave vents 18, ridge vent
14 and shingles 12 installed. Eave vent 18 is flanked by end caps
54 and covered by shingles 12. Eave vent opening 26, covered by
eave vent fabric filter 44, is exposed to air 22 outside the attic
space 6 of structure 4. The roof deck 2 is covered by shingles 12.
The roof deck ridge vent opening 16 is covered by ridge vent 14.
Ridge vent 14 also is covered by shingles 12. Ridge vent opening 24
is covered by ridge vent fabric filter 34 and is exposed to the air
22 outside the attic space 6. Air 22 enters the attic space 6
through the eave vent opening 26, passes through the attic space 6
and exits the attic space through the ridge vent opening 24. The
flow of air is controlled by selecting the eave vent fabric filter
44 and the ridge vent fabric filter 34 so that the permeability to
air of the eave vent fabric filter 44 is less than that of the
ridge vent fabric filter 34. The resistance to air flow of the eave
vent 18 therefore is greater than the resistance to air flow of the
ridge vent 14.
LIST OF NUMBERED ELEMENTS
[0064] The following are indicated as numbered elements on the
drawings. [0065] a roof deck 2 [0066] a structure 4 [0067] an attic
space 6 [0068] a ridge 8 [0069] an eave 10 [0070] shingles 12
[0071] a ridge vent 14 [0072] a roof deck ridge vent opening 16
[0073] an eave vent 18 [0074] a roof deck eave vent opening 20
[0075] air 22 [0076] A ridge vent opening 24 [0077] An eave vent
opening 26 [0078] a corrugated plastic 28 [0079] a plurality of
channels 30 [0080] a ridge vent discharge opening 31 [0081] an
underside of the ridge vent 32 [0082] a ridge vent fabric filter 34
[0083] a top of the ridge vent 36 [0084] a bottom of the ridge vent
38 [0085] a nail 40 [0086] an eave vent support 42 [0087] an eave
vent fabric filter 44 [0088] an eave vent top 46 [0089] an eave
vent bottom 48 [0090] an eave vent discharge opening 50 [0091] a
roof deck top side 52 [0092] an end cap 54
* * * * *