Abstract:
A roof ventilation apparatus for a sloped roof having a cap and base plate is provided. The cap has a top surface and a bottom surface. The bottom surface has a flange that defines an opening to a cavity formed between the top and bottom cap surface. The cavity provides a path for air exchange from a roof opening through an air passage formed between the flange and cap top. The base plate has a collar or curb surrounding an aperture that fits inside the cap bottom cavity. The base plate preferably is shaped such that when installed on the sloped roof the cap entirely covers the base plate. Preferably, the base plate includes a collar and an angled edge configured to channel moisture that seeps within the vent cap.

Description:
RELATED APPLICATIONS 
       [0001]    The present application is related to and claims priority to U.S. patent application Ser. No. 10/918,925, filed Aug. 17, 2004, currently pending, and is titled ROOF VENT AND METHOD OF INSTALLATION, wherein the aforementioned application is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to a base plate that can be used in combination with roof vent caps such as covers, stack flashings, penetrations or the like. More specifically, the present invention is directed to a base plate that directs water away from a roof exhaust source. Even more particularly, the present invention relates to a base plate having an adhesive layer such that the base plate can be easily secured to a roof deck. 
       BACKGROUND OF THE RELATED ART 
       [0003]    It is desirable to provide ventilation for the areas beneath building roofs to reduce the accumulation of heat and to reduce the accumulation of moisture in the attic or other spaces immediately below the roof, for example. In providing ventilation, it is important to prevent the entry of water into the building structure through the vent. Also, it is desirable to prevent debris and small animals from entering the building structure though the vent. Ultimately, the benefits of a properly constructed roof vent will prolong the life of the roof, virtually eliminate leaks caused by ice dams, reduce cooling bills, and reduce moisture build up in the attic that can lead to rot. 
         [0004]    To protect buildings and their contents from water damage, roofers repair and install roofs made of tar, asphalt and gravel; rubber, thermoplastic; metal; or shingles made of asphalt, slate, fiberglass, wood, tile, or other material. There are two types of roofs-flat and sloped. Slope is the change in roof height for a horizontal distance for every 12 inches of horizontal distance (e.g., “flat slope” is about 0 to about 2 inch vertical distance for every 12 inches of horizontal distance and a “steep slope” is a greater than 2 inch vertical distance for every 12 inches of horizontal distance). Many commercial, industrial, and apartment buildings have flat or slightly sloping roofs for drainage (i.e., roofs with minimum slope of less than about 2 inches of vertical distance for every 12 inches of horizontal distance). Many residential houses have steep sloped roofs having a larger slope. 
         [0005]    Flashings have been used for decades to weatherproof roof penetrations. Flashings protect the roof where moisture could get under it, such as at joints in the roof, places where a vent pipe or chimney pokes through, a valley where two roof surfaces meet, or where a roof meets a wall. Some flashings are installed before the roofing goes on, others are put in place along with the roofing. Flashing is widely used with shake, composite and wood shingles and roll roofing. Like many flashing pieces, the vent flashings are often “weaved” between shingle courses. 
         [0006]    Flashings for pipes and other roof penetrations extending out of a roof exhaust source are often constructed from thin sheet metal that is cut and formed into the desired shape. The flashing is often formed from one piece of sheet material that has a central opening cut therein to fit about the roof penetration. Thereafter, a sealing material, such as caulk or tar, is applied proximate the juncture of the roof penetration and the central opening in the sheet material. 
         [0007]    Roof vents (or turbine vents) come in many forms, but generally include some type of weather-shedding hood and a flange around the base that forms a seal between the vent and the surrounding roofing material. Some vents have a pipe that penetrates the roof surface and is exposed above the roof. Also, some vents have a tubular outside vent stack cover which is secured to a substantially flat roof flashing base plate. See, for example, U.S. Pat. No. 5,778,611 to Michel, “Vent Extension Flashing Assembly”, issued Jul. 14, 1998. In other roof vents, the pipe remains exposed through the base plate flashing assembly. See for example U.S. Pat. No. 4,333,660 to Cupit, “Seal Device for Pipe Projecting through Roof”, issued Jun. 8, 1982. Ultimately, to make a roof vent installation watertight, the most common technique is to “weave” or cover the vent flanges with roof material on the high side towards the roof ridge and along the edges of the vent, and cover the roofing material with the vent flange on the low side. 
         [0008]    Known roof vents are typically assembled from essentially planar sheet material so that a portion of the sheet material about the central opening lies in approximately the same plane as the remaining portion of the sheet material. Such construction can lead to an increased likelihood of leakage at the central opening. An example of such a roof vent is disclosed in U.S. Pat. No. 4,570,396 to Struben, “Roof structure for mobile homes”, issued Feb. 18, 1986. 
         [0009]    The present invention addresses problems and limitations associated with the related art. 
       SUMMARY OF THE INVENTION 
       [0010]    Preferred embodiments include a base plate that can be used in conjunction with a vent cap such as a cover, stack flashing, penetration or the like. The preferred base plate includes a substantially planar attachment portion and an aperture located within the attachment portion. The base plate further includes a collar or curb circumscribing the aperture; wherein the collar preferably defines a cylindrical channel. In further preferred embodiments the cylindrical channel is of a generally uniform diameter and the collar extends perpendicularly from the substantially planar attachment portion. Preferably, the collar extends upwardly when the attachment portion is operatively installed around the roof exhaust source. The preferred base plate substantially prevents any water that enters the vent cap from getting into the roof exhaust source, by diverting water away from the roof exhaust source, thus preventing leaks and resultant property damage. 
         [0011]    The base plate is preferably used in conjunction with a vent cap. One potential vent cap has a top surface and a bottom surface. The top surface is configured to cover at least a portion of the roof exhaust source. The bottom surface has a flange that defines an opening to a cavity formed between the top and bottom cap surface. The flange extends outward relative to the cavity. The cavity is configured to provide a path for air exchange from the roof exhaust source through an air passage formed between the flange and the cap top. Preferably, the collar of the base plate is shaped such that the collar fits inside the cap bottom cavity. The base plate preferably is configured such that, when installed on the roof, the cap entirely covers the base plate. Alternatively, embodiments include a base plate with a planar attachment surface having an angled edge configured to channel moisture. 
         [0012]    The preferred base plate includes an adhesive layer on a bottom surface of the generally planar attachment portion. The adhesive layer may cover a portion, most of or all of the bottom surface. The adhesive layer is preferably configured such that the base plate can be secured to the roof deck or underlayment with the adhesive. Suitable adhesives include, but are not limited to, rubberized asphalt adhesive, modified bitumen adhesives, acrylic or latex sealants or the like. In further preferred embodiments, the adhesive layer has a removable protective sheet such that the adhesive is covered until installation. This is highly preferred as it will make installation fast and easy as no separate tubes of adhesive or caulk will need to be carried or applied by the installer. In addition, this method is much less messy as there is nothing to drip or smudge. The installer can simply peel off the adhesive layer and press the adhesive onto the roof deck or underlayment. 
         [0013]    The present invention further includes methods of installing a roof ventilation apparatus on a sloped roof having an opening therethrough, the method comprising steps of mounting a base plate to a sloped roof deck, securing a roof vent cap over the collar of the base plate and finally fitting roofing material courses over the substantially planar attachment portion in a manner such that only the vent cap is exposed when the roof ventilation apparatus is installed. 
         [0014]    Additional advantages and features of the invention will be set forth in part in the description which follows, and in part, will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view of a roof ventilation apparatus installed on a roof with a portion of roof sheathing of the roof exposed. 
           [0016]      FIG. 2  is a perspective view of a roof ventilation apparatus installed on a sloped roof and revealing the attic underneath the sloped roof. 
           [0017]      FIG. 3  is a cross-sectioned view of a roof ventilation apparatus. 
           [0018]      FIG. 4  is an exploded, partially cutaway view of a roof ventilation apparatus. 
           [0019]      FIG. 5  is an exploded view of a roof ventilation apparatus. 
           [0020]      FIG. 6  is a perspective view of a base plate secured on a roof deck. 
           [0021]      FIG. 7  illustrates alternative embodiment shapes of planar attachment portions of the base plate. 
           [0022]      FIG. 8  is an alternate base plate having an adhesive layer. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    The amount of water intrusion into our homes and businesses are at almost epidemic levels. Roof leaks have always been at the top of the list for a cause of water intrusion. A good roof system requires quality materials and detailed installation. Most roof leaks occur at the penetrations or vent caps in the roof. These penetrations being attic vents, plumbing vents, vent stacks for furnaces and fireplaces, bathroom vents and the like. 
         [0024]    There are many different methods used when installing a roof-top vent caps. Sealants (e.g. tar, caulking and the like) and mastics (e.g. ice and water shield) are the practiced method used to make vent openings or roof exhaust sources leak-proof. The inventor has found that the use of sealants and mastics can be messy and can actually damage the roof system if not properly used. Moreover, these sealants and mastics can be subject to UV degradation. Expansion and contraction from weather extremes can further damage their effectiveness in preventing leaks. 
         [0025]    The preferred base plate, as further discussed below, provides a second layer of protection from roof leaks that occur at roof exhaust sources. The base plate is preferably installed under the roof covering and is not “weaved in” with the roof covering. The inventor has found that the weaving process can result in leaks. The base plate creates a “curb” at the roof exhaust source which will generally stop any liquid that may leak through the vent installation from entering the roof exhaust source. 
         [0026]    Preferred embodiments are illustrated in  FIGS. 1-8 .  FIGS. 1-4  are a series of views illustrating a roof ventilation apparatus  100  that can be secured on sloped roofs for preventing leakage of a roof exhaust source such as a plumbing, attic or furnace vent. The preferred roof ventilation apparatus includes a vent cap  102  and a base plate  201 . The inventor has found that the present invention is particularly beneficial when the slope of the roof, is greater than about 2 inches of vertical distance for every 12 inches of horizontal distance.  FIG. 1  illustrates a roof including shingles  114  secured to a roof sheathing  107 . In  FIG. 2 , the roof ventilation apparatus  100  is illustrated as being installed on a shingle roof to ventilate an attic  101 . It will be appreciated by those skilled in the art that the base plate  201  can be used in conjunction with almost any kind of roof vent opening or exhaust source such as pluming vents, furnace vents or the like. It will be understood that, shakes, tiles, and other roofing materials can be used in alternative of shingles  114 .  FIG. 2  also illustrates a ridge  105  and roof deck  116 . 
         [0027]      FIG. 3  is a cross-sectioned view illustrating one roof ventilation apparatus  100  having the vent cap  102  secured over a planar attachment portion  108  of the base plate  201 . Now also referring to  FIG. 4  showing an exploded, partially cutaway view of the roof ventilation apparatus  100  with the same parts shown in  FIG. 3 . The substantially planar attachment portion  108  of the base plate  201  is positioned on roof deck  116  having a roof exhaust source  120 . The base plate  201  is positioned such that a collar or curb  110  circumscribing an aperture in the base plate is extending outwardly and generally perpendicularly from the roof deck  116 . Preferably, however, the base plate  201  is secured over the roofing paper or alternative underlayment  106  with nails  124 , screws, adhesives or the like. The roof exhaust source  120  can be any regular or irregular shape. Roofing paper  106  or the like can be secured over the substantially planar attachment portion  108 . In the alternative, asphalt—impregnated felt or other underlayments can be used in conjunction with or substituted for roofing paper  106 . In various embodiments, caulk bead  118  can be used to seal roofing paper  106  over the substantially planar attachment portion  108  and the base plate collar  110 . It will be appreciated by those skilled in the art that the caulk bead  118  may be omitted or other forms of adhesive may be used instead of caulk bead  118 . In various embodiments, the vent cap  102  is then fitted over the base plate  201  such that vent cavity  112  encircles base plate rim or collar  110 . Vent cavity  112  and the base plate collar  110  can be formed in a wide variety of shapes. In preferred embodiments, base plate collar  110  has a uniform diameter (e.g. 8 inches) that is smaller than the cap bottom surface cavity  112  (e.g. having a largest planar dimension of 8½ inches) so that the collar nests within the bottom surface cavity  112 . It will be appreciated by those skilled in the art that vent cap  102  can be either loosely or tightly fitted around base plate  201 . In preferred embodiments, the bottom surface flange  104  entirely covers the base plate  201  after installation. Shingles  114  can then installed over cap bottom surface flange  104 . Moisture is not likely to enter the roof exhaust source  120  because bottom surface flange  104  entirely covers base plate  108  over roofing paper  106 . In addition, the collar  110  of the base plate  201  redirects moisture contacting the collar  110  away from the roof exhaust source  120 . Preferably, only the vent cap top  103  is visible on the roof after installation of the roof ventilation apparatus  100 . 
         [0028]      FIG. 5  is an exploded view of the roof ventilation apparatus  100 .  FIG. 5  shows the base plate  201  being installed on a roof deck  116 . It will be appreciated by those skilled in the art that the base plate  201  can be installed on any type of roof deck and roof sheathing, such as plywood. Moreover, the base plate  201  can be secured over the underlayment or roofing paper  106 . The preferred base plate is constructed from a twenty to twenty-five gauge galvanized steel, for example. This material is preferred due to its lighter weight and manageability as compared to heavier gauge steel. Other alternative materials can be used for constructing the base plate, such as aluminum, copper, urethanes, and polymers. However, it will be appreciated by those skilled in the art that galvanized metal is preferred over polymers because it is believed, but not relied upon, that polymers tend to crack and curl with changing weather and are less weather resistant than metal. 
         [0029]    Referring also now to  FIG. 6  that illustrates the substantially planar attachment portion  108  covered by the roofing paper  106 .  FIG. 6  additionally illustrates the roof deck  116  located underneath both the base plate  201  and roofing paper  106 .  FIG. 7  illustrates some possible alternative base plates  201 ,  202 ,  203 ,  204 ,  205  having different substantially planar attachment portions  108 . Alternatively configured substantially planar attachment portions  108  of base plates  201  and  204  include peaked corners  122  that angle moisture away from the rim or collar  110 . Another alternative substantially planar portion (not shown) could have a peaked corner off center or even moved to one corner such that the angle goes from a peak at one corner to a low point at another corner. Alternative planar attachment portion  108  of a base plate  205  has dubbed corners that channel moisture down the sides of the substantially planar attachment portion  108  away from base plate rim or collar  110 . When installed, both the peaked and dubbed corners preferably point towards the high side of the roof (i.e., towards the roof ridge  105 ) and prevent the entry of moisture into the roof opening. Alternative embodiment base plates  202  and  203  illustrate alternative shapes of the attachment portion  108  that channel moisture away from the base plate collar  110  along a curved edge but otherwise similar to the mechanism provided for in the peaked and dubbed corners of alternative planar attachment portions of base plates  201 ,  204 , and  205 . 
         [0030]    Yet another preferred embodiment is illustrated in  FIG. 8 .  FIG. 8  illustrates a base plate  206  that includes an adhesive layer  134 , preferably a rubberized asphalt adhesive or the like, applied to the bottom surface  132  of the planar attachment portion  130 . This will enable the base plate  206  to adhere and bond to the roof deck  107  (or alternatively, underlayment or the like  106 ). In addition, the adhesive layer  134  will help insure complete adhesion at the roof exhaust source  120  and eliminate the use of messy tar, caulk or mastics. The adhesive layer  134  will not be exposed to UV degradation. This will insure adhesion through any expansion or contraction that may occur. Installers previously have had to depend on sealants or mastics which are liquid penetrable. 
         [0031]    In preferred embodiments, the adhesive layer  134  is of the type as to additionally create a generally leak-proof ice and water barrier at the bottom surface  132  of the planar attachment portion  130 . Examples of such an adhesive are rubberized asphalt adhesive, modified bitumen, acrylic or latex sealants or the like. It will be understood that the adhesive layer  134  need not cover the entire bottom surface  132 . 
         [0032]    A release paper or protective sheet  136  is preferably applied over the adhesive layer  134  to protect the adhesive layer until the time for installation. At the time of installation, the release paper  136  can be easily peeled or otherwise removed to expose the adhesive layer  134 . 
         [0033]    Preferred embodiments include the adhesive layer and protective sheet to make installation fast and easy as no separate tubes of adhesive or caulk will need to be carried or applied by the installer. In addition, this method is much less messy as there is nothing to drip or smudge. The installer can simply peel off the adhesive layer and press the adhesive onto the roof deck or underlayment at the time of installation. 
         [0034]    The present invention further includes methods of installing a base plate  201 ,  202 ,  203 ,  204 ,  205  for preventing vent cap  102  leaks from entering into a roof exhaust source. The preferred method includes the steps of providing a roof deck  107 ,  116  having a roof exhaust source  120 . Additionally, a base plate  201 , 202 ,  203 ,  204 ,  205  is provided. The preferred base plate having a substantially planar attachment portion  108  and an aperture located within the substantially planar attachment portion and a collar  110  circumscribing the aperture. The base plate is then secured to the roof deck, preferably, by removing the protectant sheet  136  to expose the adhesive layer  134 . The base plate can then be pressed onto the roof deck, or alternatively, underlayment  106 . If the base plate does not include an adhesive layer, adhesive or caulk can be applied to secure and seal the base plate to the roof deck. The base plate is positioned such that the aperture of the base plate surrounds the roof exhaust source and the collar extends upward therefrom. The next preferred step is to secure roofing materials  114  over at least a portion of the substantially planar attachment portion and then to fit the vent cap over the base plate. Next, preferably roofing materials are secured over at least a portion of the vent cap. 
         [0035]    It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.