Abstract:
A method and apparatus for providing ventilation to a building structure&#39;s roof is provided. The apparatus provides a low profile roof vent having improved resistance to bending and thus increased resistance to damage caused by the wind or other forces. Particularly, the apparatus provides a roof vent having generally I-beam shaped internal bracing in both vertical and horizontal directions. Thus, the apparatus of the present invention provides a roof vent that is highly resistant to failure due to exposure to strong winds. The present apparatus also offers improved air flow through the roof vent. The method of the present invention comprises providing a roof vent having a passageway that includes a front and a rear section. The rear section is in communication with a hole in the roof, while the front section is in communication with an exterior of the structure. A baffle between the hole and the exterior of the structure, along the surface of the roof, prevents water from entering the hole directly. The method further includes providing internal bracing to provide increased resistance to bending and thus increased resistance to damage caused by the wind or other forces applied to the vent.

Description:
FIELD OF THE INVENTION 
     The present invention relates to vents for installing in building roofs. In particular, the present invention relates to roof vents featuring improved resistance to failure due to the effects of wind or other external loads. 
     BACKGROUND OF THE INVENTION 
     There are various designs in existence for providing ventilation for the areas beneath building roofs. The ventilation of such areas is desirable to reduce the accumulation of heat in the summer, and to reduce the accumulation of moisture during all times of the year. In providing ventilation, it is important to prevent the entry of water into the structure through the vent. Also, it is desirable to prevent debris and small animals from entering the structure through the vent. 
     Existing off-ridge roof vent designs are available in various configurations. One such design consists of simply a duct having a baffle mechanism over the top to prevent the entry of rain into the structure. A variation of this simple design is the turbine type roof vent, which consists of a rotating element on the exterior of the duct and interior baffles to prevent the entry of water into the building. However, both such designed provide only a limited area through which air and moisture may escape from the structure. Also, such designs typically extend a considerable height from the surface of the roof, making them vulnerable to being knocked from the roof by tree limbs, wires, or simply the wind itself. 
     Other designs fit more closely to the surface of the roof, and provide a long rectangular opening through which air and moisture may exit the structure. Generally, a slot is cut in the roof that is slightly smaller than the foot print of the vent. The slot then communicates with a passageway that, in profile, is generally in the shape of an inverted J. Thus, the opening of the vent faces down, towards the roofing surface. In this way, water is prevented from entering the structure. Such vents may also be provided with a mesh or screen covering the opening, to prevent the entry of debris or small animals into the structure. 
     However, existing low profile designs suffer from a number of disadvantages. For example, such designs are vulnerable to damage by wind or by impacts from debris. This is because the relatively large area of the opening is unbraced throughout the center of the vent. As a result, even relatively mild winds are capable of exerting sufficient force to damage the device. Typically, damage from the wind to such vents is in the form of bent or deformed top pieces or hoods. Such damage makes the vent more easily penetrated by rain and debris, because portions of the vent opening are enlarged, and often results in deformation of those portions of the vent that interface with the surface of the roof, thus interfering with the proper sealing of the vent to the roof surface. Damage from debris or from careless workers walking on the roof often occurs as crushed or otherwise inwardly deformed top pieces or hoods. This type of damage impedes the movement of moisture and air through the vent and is unsightly. In addition, existing vents can be deflected by the wind or forces to an extent short of what is required to cause permanent damage to the vent. However, such deflection is undesirable for several reasons. Where the opening of the vent is enlarged, rain may more easily enter the structure through the vent. Where the opening of the vent is made smaller, the movement of air and moisture through the vent is impeded. Also, existing designs have a top piece or hood which offers little clearance between itself and the interior baffle, limiting the amount of air that can move through the slot. 
     Although the prior art describes designs for providing through-roof ventilation to structures, it would be advantageous to provide a design which provided a vent that resists deflection and bending caused by the wind or other forces. In addition, it would be advantageous to provide such a design which had a low profile, and which offered a relatively unimpeded flow of air and moisture from the area beneath the roofing surface to the outside atmosphere. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, an apparatus for providing through roof ventilation to a structure is disclosed. In particular, an apparatus for providing ventilation to the attic space of a structure, having improved flow characteristics and improved resistance to damage from wind or from crushing is disclosed. More particularly, the present invention provides an apparatus that resists deflection and bending due to the effects of the wind or other forces. The apparatus generally comprises left and right sidewalls at either end of a hood having a back flange for alignment with the roof&#39;s surface, a rear surface rising from the roof, a top, and a header extending from the top towards the roof surface. The header does not extend all the way to the roof surface, but instead forms a gap through which air may pass. The vent further includes a baffle extending from the left sidewall to the right sidewall in a plane that is substantially perpendicular to the plane of the roof. The baffle is coincident with the roof on a first edge, and extends to a line between the sidewalls that is short of the top of the hood, such that a gap between the top of the baffle and the top of the hood is formed. This baffle thus prevents water that enters the vent through the gap between the header and the roof from entering the portion of the vent between the rear surface of the hood and the baffle, where air exits the attic and enters the vent, thus preventing water from entering the interior of the structure. 
     The roof vent of the present invention provides increased stiffness and resistance to damage from wind or from crushing by providing internal braces. Thus, a hood brace extends from the top of the baffle in a substantially vertical direction to interconnect with the top of the hood. In this way, an I-beam type structure is created inside the roof vent, enabling the roof vent to resist deformation or bending from even strong winds or other forces. More particularly, a structure is formed having the characteristics of two I-beam type structures stacked one on top of the other. In addition, a header brace is provided which extends from the top of the baffle to a distal edge of the header. Furthermore, the header is, when viewed in profile, generally in the shape of an I-beam structure. This provides great resistance to movement in response to bending or torsional forces applied to the header by the wind or other external effects. Where the roof vent is particularly long, a plurality of hood braces and header braces may be provided. In addition, header braces and hood braces need not be used in combination. In addition to the improved resistance to damage from external forces, the roof vent of the present invention provides increased flow volumes by providing a deep (or tall) header. The depth of the header allows more space between the top of the hood and the top of the baffle, without compromising the resistance of the vent to intrusion by water. 
     In one embodiment, the roof vent of the present invention features screen or wire mesh material between the top of the baffle and the edge of the header. In a preferred embodiment, the screen rests on top of screen support clips also running between the top of the baffle to the edge of the header. 
     In a preferred embodiment, the top of the baffle includes a forwardly extending rain return portion or shelf. The rain return offers further resistance to intrusion by water into the interior of the structure by forming a more convoluted path between the interior of the structure and the outside atmosphere. In yet another embodiment, the header brace is formed such that it is crimped about an exterior lip of the header, improving the resistance of the hood to damage from wind. In a further embodiment, the hood brace is affixed to the baffle by crimping at a first end, and to the interior surface of the hood by adhesive. 
     According to one embodiment of the present invention, the roof vent is formed from galvanized steel. In a further preferred embodiment, the hood brace and header brace are formed from 16-gauge galvanized steel, while the sidewalls, hood, and baffle are formed from 26-gauge galvanized steel. In other embodiments, the roof vent may be formed from a variety of materials having a variety of thicknesses. Preferably, the material is resistant to corrosion, so that it is suitable for use on the exterior of a building, and is sufficiently ductile to be formed by crimping and bending. 
     The roof vent of the present invention may be provided in a wide variety of sizes. For example, the roof vent of the present invention may be provided in sizes ranging from about 2 feet to about 10 feet in length. However, sizes outside of the aforementioned range are encompassed by the present invention. The only constraint on size is the size of the roof to which the vent will be installed. Generally, the volume of the attic to be ventilated determines the size of the vent. Depending on the length of the vent, a varying number of hood braces and header braces may be provided. The number of braces may also be varied according to the desired resistance to damage from wind or crushing. Thus, a roof vent to be installed in a structure that will be subject to high winds may be provided with a greater number of braces to improve the vent&#39;s resistance to wind damage. 
     The vent of the present invention may also be provided with side flanges extending from the sidewalls of the vent. In addition, these side flanges may be provided with water hems. Water hems, which are formed by folding the edge of the flange back on itself almost but slightly less than 180°, prevent water from entering the structure by passing between the top of the side flange and the bottom of roofing material. 
     Based on the foregoing summary, a number of salient features provided by the present invention may be discerned. The present invention allows a vent that has improved resistance to deformation and permanent damage by wind or by other forces. The vent also offers an improved flow volume, increasing the efficiency with which the area beneath the roof is vented. The invention also provides these benefits while offering improved resistance to intrusion into the structure by rain. In one embodiment, a screen between the baffle and the header prevents debris and small animals from entering the structure through the vent. Preferably, this screen is held in position by clips, facilitating assembly and retaining the resistance of the material to corrosion. 
     Additional advantages of the present invention will become readily apparent from the following discussion, particularly when taken together with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the roof vent of the present invention, with the sidewall removed; 
     FIG. 2 is a detail of the interconnections between the various components at the top of the baffle and at the distal edge of the header; 
     FIG. 3 is a front elevational view of the roof vent of the present invention, showing the hood braces in phantom; and 
     FIG. 4 is a bottom sectional view of the roof vent of the present invention taken along line  4 — 4  of FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     In accordance with the present invention, a roof vent apparatus is provided for ventilating spaces beneath the roofs of building structures. 
     With reference to FIG. 1, the roof vent  104  of the present invention is shown in profile, with the left sidewall removed. In general, the roof vent is comprised of a hood  108  and a baffle  112 . In addition, the roof vent  104  includes a hood brace  116  and a header brace  120 . The hood  108  generally includes a back flange  124 , a rear surface  128 , a top  132 , and a header  136 . The hood  108  generally has a constant cross section across its entire length, and extends without interruption between the left and right sidewalls. Generally, the back flange  124  is parallel to the plane of the roof surface  140 . 
     The baffle  112  generally includes a front flange  144 , a riser  148 , a rain return  152  and a channel  156 . The aforementioned components generally comprise a first I-beam type structure. The front flange  144  is generally parallel to the plane of the roof surface  140 . The riser  148  extends from the roofing surface  140  to a height above the roofing surface  140  that is approximately equal to the height of the distal edge  158  of the header  136  above the roof surface  140 . Thus, a ventilation outlet  160  is formed between the baffle  112  and the header  136 . In addition, the baffle  112  features side rain return tabs  162  at either end. 
     The hood brace  116  interconnects with the baffle  112  at the channel  156 . According to one embodiment of the present invention, the hood brace  116  is secured in the channel  156  by crimping the channel  156  about the forwardly extending lower support  164  of the hood brace  116 . In another embodiment, the hood brace  116  is secured to the baffle using adhesive. The hood brace  116  extends from the top of the baffle  112  in a substantially vertical direction, to meet the top  132  of the hood  108 . A support surface  168  is formed at the top of the hood brace  116  to provide support for the top  132  of the hood  108 . The hood brace  116  and its interconnections to the top  132  of the hood  108  and to the channel  156  of the baffle  112  generally comprises a second I-beam type structure. According to one embodiment of the present invention, the support surface  168  is affixed to the top  132  of the hood  108  using adhesive  172 . The width of the hood brace  116  is a fraction of the width of the entire roof vent  104 , to avoid unduly limiting the flow of air through the vent  104 . 
     The header brace  120  extends from the top of the baffle  112  in a generally horizontal direction. According to one embodiment, the header brace  120  is joined to the baffle  112  by crimping. According to other embodiments, the header brace  120  may be joined to the baffle  112  by an adhesive, or a combination of adhesive and crimping. Similarly, the interconnection between the header brace  120  and the header  136  may be formed by crimping, adhesive, or a combination of adhesive and crimping. As with the hood brace  116 , the header brace  120  is much narrower in width than the width of the roof vent  104  itself, to avoid unduly impeding the flow of air through the vent. The header brace  120  and its interconnections between the baffle  112  and the header  136  generally comprises a third I-beam type structure. 
     The roof vent  104  may also include a mesh or screen  176  supported at intervals by clips  180 . The mesh  176  prevents the entry of debris or small animals through the outlet  160 . The size of the mesh  176  or screen may be varied depending on the environment in which the roof vent will be used. The support clips  180  are provided at intervals, to avoid impeding the flow of air through the outlet  160 . Preferably, the support clips  176  are sized such that they hold the screen  180  in position using only friction. This avoids destroying the weather resistance of galvanized materials, as would occur with welding, allows the screen  176  to be easily removed for maintenance, and simplifies assembly. 
     Referring now to FIG. 2, a detail of the various interconnections at the top of the baffle  112  and the front edge of the header  136  are illustrated. In particular, it can be seen that baffle  112  makes a 90° turn towards the front of the vent  104  to form the rain return  152 . The baffle  112  then turns back on itself, towards the rear of the vent  104  to form channel  156 . Channel  156  receives the lower portion  164  of the hood brace  116 . In addition, channel  156  receives the rear of the header brace  120 . As described above, the hood brace  116  and header brace  120  may be held in channel  156  by the friction caused by the crimp in the baffle  112 . Alternatively, the hood brace  116  and header brace  120  may be held in channel  156  using adhesives, adhesive in combination with friction, or by spot welding. In yet another embodiment, the hood brace  116  and header brace  120  may be affixed to the baffle  112  by riveting, or by using threaded fasteners. 
     Also in FIG. 2, the interconnection between the header brace  120  and the header  136  can be seen. The header brace  120  extends in a generally forward or horizontal direction from the baffle  112  to form a channel  184 . Channel  184  extends around channel  188  formed in the distal edge  158  of the header  136 . The channel  188  of the header  136  in turn receives the screen clip  180  and the screen  176 . 
     The channel  188 , the header  136 , and the transition from the header  136  to the top  132  of the hood  108  generally comprises a fourth I-beam type structure. 
     In one embodiment, the interconnection between the header brace  184  and the header  136  is secured by crimping the header brace  184  about the header  136 . As with the interconnection between the baffle  112  the hood brace  116  and the rear portion of the header brace  120 , the interconnection between the header brace  184  and the header  136  may be secured using adhesive, a combination of adhesive and friction, or using mechanical fasteners, such as threaded fasteners or rivets. 
     The screen clip  180  is, in one embodiment, held in position by friction between the header channel  188  and the hood brace  116 . Screen clip  180  supports the screen  176 . Screen  176  generally comprises a wire mesh or screen sized to prevent the entry of debris and animals into the structure through the roof vent  104 . Friction fitting of the screen clip  180  and the screen  176  is preferred because it allows for the easy removal of the screen  176  for cleaning or replacement. However, in other embodiments, the screen clip  180  and screen  176  may be secured to the header  136 , header brace  120 , baffle  112 , or hood brace  116 , in various combinations, using adhesives, welds, or mechanical fasteners. 
     Referring now to FIG. 3, a front elevation of a roof vent  104  according to one embodiment of the present invention is illustrated. The major surfaces illustrated in FIG. 3 are the left side panel  304 , the right side panel  308 , the header  136 , and the baffle  112 . Also, the distal edge  158  of the header  136  can be seen. 
     In the embodiment illustrated in FIG. 3, there are two hood braces  116 , illustrated in phantom, and two header braces  120 . The hood braces  116  are illustrated in phantom because, in this view, they are obscured by the header  136 . Also, with respect to the header braces  120 , the specific portion of each brace  120  that is visible is the exterior of the channel  184 . Although two hood braces  116  and two header braces  184  are illustrated in FIG. 3, a longer roof vent  104  may feature more such braces  116  and  120 , while a shorter roof vent  104  may feature fewer. Additionally, a particular roof vent  104  may have more or fewer braces  116  and  120  depending on the conditions it is expected to encounter when installed, and the desired level of strength. 
     The view of the roof vent illustrated in FIG. 3 also shows the configuration of the left side flange  312 , the left side water hem  316 , the right side flange  320  and the right side water hem  324 . Generally, the left  312  and right  320  side flanges provide a surface for affixation to the roof surface. Water hems  316  and  324  prevent water from reaching the interior of the structure by passing between the shingles or other roofing material (not shown) of the roof. Instead, water that moves laterally along the side flanges  312  and  320  becomes trapped in the water hems  316  and  324  and is carried to the forward portion of the side flanges  312  and  320 , where it can be directed to the outer surface of the roofing material. 
     In FIG. 4, a section of a roof vent  104  according to the present invention, taken along line  4 — 4  in FIG. 1, is illustrated. In FIG. 4, the screen or mesh  176  can clearly be seen. Generally, the mesh  176  has its edges carried by the channel  188  of the header  136 , the top of the channel  156  and the baffle  112 , and by screen support flanges  404  and  408  formed in the left  304  and right  308  sidewalls of the roof vent  104 . The size of the screen or mesh  176  will depend on the area in which the roof vent  104  is installed. Thus, where there are trees in the area that might produce small debris, a smaller hole size in the screen or mesh  176  is called for. Where there is little risk of infiltration by small debris, but small animals are in the area, a larger, sturdier mesh  176  may be desired. 
     Header braces  120  can be seen to extend from the channel  156  of the baffle  112  to the exterior of the channel  188  of the header  136 . In the embodiment illustrated, screen clips  180  (not illustrated) are located immediately above the header braces  120 . 
     FIG. 4 also illustrates the relationship between the side rain return tabs  162  of the baffle  112 , and the left  304  and right  308  sidewalls of the roof vent  104 . The side rain return tabs  162  extend from the baffle  112  at a 90° angle to the baffle towards the front of the roof vent  104 . This allows the side rain return tabs  162  to function as a rain return, and eliminates the need to otherwise seal the interface between the side tabs  162  and the sidewalls  304  and  404  against intrusion by water. In a preferred embodiment, each side rain return tab  162  is affixed to a corresponding sidewall  304  or  308  to further stabilize and stiffen the roof vent  104 . Methods for affixing the side rain return tabs  162  to the sidewalls  304  and  308  include adhesives or mechanical fasteners. In a most preferred embodiment, the side rain return tabs  162  are riveted to the sidewalls  304  and  308 . 
     In use, the roof vent  104  is generally positioned above a rectangular hole. Referring again to FIG. 1, a hole  192  is illustrated. The hole  192  is sized in such that it is completely enclosed within the inlet passage-way  196  of the roof vent  104 . Thus, the only way for air and moisture to exit the interior of the structure is to travel up through hole  192  and through the passage-way  196 . The air may then pass over the baffle  112 , around the top braces  116  through the screen  176  and around screen clips  180  and header braces  188 , to exit through the outlet  160 . 
     The roof vent  104  is affixed to the roof  140  using adhesives or mechanical fasteners, such as screws, bolts, nails, or staples applied at the back flange  124 , front flange  144 , left side flange  312  and right side flange  320 . Typically, roofing material will be installed over the back  124  and side  312  and  320  flanges to insure that water is not able to infiltrate the structure by leaking beneath the roof. For the same reason, the front flange  144  typically rests on top of the roofing material. 
     Water is prevented from entering the hole  192  from directly above by the hood  108 . The sidewalls  304  and  308  prevent water from entering from the sides. From the front of the roof vent  104 , water is prevented from entering by the baffle  112  and the rain return  152 , in combination with the header  136 . These components form a convoluted path which must be traversed in order for water to enter the structure through the hole  192 . 
     The foregoing description of the present invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are within the scope of the present invention. The embodiments described hereinabove are further intended to explain best modes known for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifications required by the particular applications or uses of the present invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.