Ventilation – Having inlet airway
Reexamination Certificate
2002-08-26
2003-12-30
Joyce, Harold (Department: 3749)
Ventilation
Having inlet airway
C454S276000, C454S283000
Reexamination Certificate
active
06669554
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
REFERENCE TO MICROFICHE APPENDIX
Not applicable
FIELD OF THE INVENTION
The present invention relates generally to ventilation of crawlspaces beneath buildings and more specifically to a method for using a modified sill plate as a sill, vent, and drip edge.
BACKGROUND OF THE INVENTION
Ventilation of the crawlspace beneath a building is imperative to prevent moisture build-up and consequent moisture damage to floor joists, sill plates, rim joists, floor sheathing, girders, posts, and other structural elements exposed to moisture in the crawlspace. Ventilation also helps to prevent the build-up of potentially harmiful or explosive gasses such as methane, natural, ozone, and radon gas. A variety of methods for providing crawlspace ventilation have been used since buildings have been placed upon enclosed foundations. Various regional and national building codes have been enacted over the years which govern the exact amount of venting required for enclosed crawlspaces. Customarily, venting devices for crawlspaces take two forms; the first is a rectangular opening in the concrete, block, brick, or masonry wall hereinafter called a “foundation wall.” The second form is a rectangular opening in the rim joist between the top of the sill, sole, or mud plate hereinafter called a “sill plate,” and bottom of the floor sheathing.
Although efficiently serving their intended purpose for more than 100 years with only minor improvements, the unsightly partial prior art venting devices nevertheless suffer from a set of drawbacks.
A rectangular foundation vent box is disclosed in U.S. Pat. No. 5,444,947 (Miller) and is typical of the latest design and technology of rectangular vents. Millers' vent can be used in many applications other than just foundations, due to its unique features. However, it is still a rectangular vent and as such is very difficult to both hide it from view and obtain continuous uniform cross ventilation. Construction standards over the past 50 years have created a standard size of rectangular vents which is on the order of eight inches tall by fourteen inches wide. The design idea is to allow it to fit between framing members, which generally are sixteen inches on center or, greater. This puts them in our direct line of sight with no simple way to hide or conceal them. For example, rectangular vents in the foundation must be located far enough above the existing finished exterior grade to prevent surface water from leaking into the crawlspace, such that there is a plurality of exposed rectangular vent openings along the periphery of the exterior foundation. Furthermore, said vent's dictate the distance from the finished interior floor to the exterior finished grade. Whereas, building codes dictate a separation from the finished grade to the wood structure above, in the range of six to eight inches, that distance must be increased when using rectangular vents'. Conventional practice is to installed said vents as close to the top exposed portion of the foundation wall as possible, in order to minimize the number of steps to grade.
Additional problems arise with the installation of rectangular vents in foundation walls. They must be coordinated with the form work of the poured-in-place concrete foundation wall, the placement of the rebar steel and, the anchor bolts that tie the sill plate to the foundation. Three things that can and often do go wrong during construction. Furthermore, when vents are installed near the top off the foundation wall, structural concerns arise if point loading occurs in the same spot.
Ideally, rectangular vents must be spaced as uniformily as possible around the entire perimeter of the foundation wall in order to achieve good cross-ventilation of the crawlspace. This will exposed the vent openings in locations that are difficult to conceal. Various attempts to hide them have included the use of plants, decorative vent covers, berming of soil, and pressure treated vent-well boxes. These attempts have proven prohibitively expensive, difficult to install and maintain, and reduce the required trough air flow. Additionally, a vent will compete or conflict with other building elements for the same space, such as; concrete patios', walkways, decking structures and, beams. This competition will force the grouping of many vents together in the remaining free areas of the building's perimeter. Effectively dropping the level of required cross-ventilation, thus increasing the risks associated with poorly vented crawlspaces.
Rim vents also follow the same pattern and configuration as foundation vents, offering approximately the same amount of net free air flow. They are commonly made out of wood and more typically found on flat lot buildings where the foundation either is not exposed enough or has already been poured. This puts rim vents higher up the exterior wall assembly than the alternative and does allow a significant reduction in the distance from the finished floor elevation to the finished grade. Unfortunately, rim vents must be installed in the rim, between the floor joists and conflict with the batt insulation which is usually stuffed in that same space. This will effectively reduce or block the rim vent's trough air flow. Furthermore, by placing a vent higher up the exterior wall assembly its unsightly nature is more visible. This has never been a desirable option.
If these existing venting solutions can be considered prior art, they can both be said to suffer the same fate. They are exposed rectangles which are unpleasant to look at, and offer no effective way hide them from view without impacting venting efficiency. Further, they only function as vents. The current invention seeks to replace them completely.
A sill, sole or mud plate for use along the top periphery of conventional foundations or floor slabs has existed since the invention of lumber. It has also changed little in the past centuries other than the discovery that it must withstand moisture in order to minimize rotting. The definition of a sill plate can be found in any dictionary published.
Random House Websters's Unabridged Dictionary
defines a sill plate this way; 'sill (sil), n. 1. A horizontal timber, block or the like serving as a foundation of a wall, house, etc. A conventional sill plate is generally a two inch tall by four or six inch wide piece of rot resistant or chemically treated solid lumber laid flat along the top of a foundation. However, it has no provisions for air transmission at all. Additionally, the conventional sill plate's exterior lateral face is generally flush with the front exterior lateral face of the foundation and, is designed to accept shear wall nailing of wall sheathing disposed directly above. Therefore, the traditional rectangular shape of a conventional sill plate or prior art beam, precludes any form of integral drip edge extension. It has a solitary function as a standoff attachment between the frame of a wood structure and the foundation wall below.
Accordingly, there exists a need for another natural venting solution which is both uniform along the exterior perimeter of the foundation, while being hidden from view. Combining crawlspace ventilation with a sill plate is unobvious enough to have never been considered prior to this invention. Additionally, the advent of newer composite-wood materials makes this invention more viable.
Continuous horizontal ventilation devices do exist for ventilating attics or walls. Roof eaves and ridges take advantage of openings cut along the horizontal length of said devices to provide a means for allowing uniform trough air. Many patents exist for improving the air flow while reducing pest or water mitigation. Yet, none have the need for high structural compressive strength found along the top of a foundation. Therefore, no embodiment of prior art for horizontal roof or wall ventilators could ever be used in place of a plate or sill i
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