Patent Application
20130042547
The present invention relates to an apparatus and method for decreasing rot and insect damage to in-ground wood and thereby increasing the effective life of the wood, and more specifically relates to a barrier system for in-ground wood that prevents microbes and insects from gaining access to the wood and prevents leaching of chemical preservatives and the like from the wood into the soil.
Wooden poles of a variety of descriptions are sunk into the ground for use as supports. Examples include posts for fencing, supports for decking and other structures, and utility poles. Wooden poles are used as fence posts for many different styles of fences because they are both highly functional and often very attractive. Although there are many techniques for building fencing using wooden posts, in a typically situation the post is sunk into the ground, typically in a pre-drilled or pre-dug hole, which is then filled in with soil, gravel or concrete. Some type of railing is then attached to the poles to complete the fencing.
The effective life of in-ground wood such as a wooden fence post depends on a variety of factors, including for instance the species of wood that is used, the soil conditions including the amount of moisture in the soil and the composition of the soil—microbial-caused caused decomposition of wood fiber eventually results in rot and insect damage can further weaken the posts. While some species of wood such as some types of cedar are notoriously long-lasting as fencing posts, all in-ground wood will eventually decompose and the post will therefore fail and need to be replaced. In some areas where there is significant moisture in the ground, wooden fence posts can fail in a matter of years from the combination of bacterial and other microbial decomposition of the wood and insect damage.
Treated wooden fencing has significantly improved the longevity of in-ground wooden posts. Treating wooden posts involves applying preservatives of various types to the wood so that microbial and insect degradation of the wood fibers is slowed or stopped. Treatments can include simple application of liquid preservatives, and more complicated processes that involve applying preservatives to the wood under pressure so that the preservatives penetrate into the wood.
Regardless of the way in which the wood is treated, the preservatives that are used often contain dangerous and toxic chemicals that could be harmful to health, or at least raise questions about their proper use in the environment. When pressure treated wood is used for in-ground applications such as fence posts, some of the chemicals used as preservatives can leach into the soil and the United States Environmental Protection Agency recommends that wood treated with the commonly used preservative chromated copper arsenate (“CCA”) should not be used in proximity to edible plants.
For these and a variety of other reasons, more and more consumers are questioning use of products that add such toxins to the soil and are therefore seeking out alternatives to use of treated wood. There is a need therefore for improved alternatives for use of wood for in-ground posts.
The present invention provides an apparatus and method for overcoming the problems of rapid wood decay and possible leaching of toxic compounds into the soil from treated wood products. The invention facilitates improved longevity of in-ground wood and even in circumstances where treated wood is used, the present invention prevents leaching of toxic compounds from the in-ground portion of the wood into the soil.
The invention is defined by a waterproof sleeve that surrounds the post below ground level and extends to a level just above ground level, and a collar that surrounds the post where it emerges from the ground. The sleeve defines a barrier between the post and surrounding soil that prevents migration of water across the barrier, and prevents microbes in the soil from exposure to the wood and associated decomposition, and prevents insects from gaining access to the wood. The collar is designed to encircle the post at the ground level and to surround the upper portion of the sleeve. The collar prevents moisture and debris from entering the sleeve, yet allows for evaporation of moisture from the sleeve and from within the interior of the collar.
The invention will be better understood and its numerous objects and advantages will be apparent by reference to the following detailed description of the invention when taken in conjunction with the following drawings.
A first illustrated embodiment of an apparatus 10 for protecting in-ground wood according to the present invention is illustrated in
The invention is described with reference to use of the invention with an in-ground fence post. It will nonetheless be appreciated that the invention is not limited to use with fence posts but instead may be used with any type and size of in-ground wood, such as deck supports, telephone and utility poles, and the like. The posts may have any cross sectional configuration, such as square, round, or irregular.
Sleeve 12 defines a waterproof casing that encloses the post 14 where the post is below the ground level 18—dimension C,
There are numerous plastic compounds that are appropriate for sleeve 12, including as noted polyethylene; other polymers will work suitably well, too. The polyethylene may include compounds that enhance the stability of the sleeve over long periods of time and exposure to moisture in the ground and to conditions existing in subsurface conditions. The material used for sleeve 12 should be thick enough to be puncture and tear resistant in use; a standard thickness of about 6 mil has been found to be effective although the thickness may vary as appropriate. Importantly, the sleeve must be wholly intact at all points where the sleeve encases the post in the ground in order to define a waterproof barrier around the post. The length of the sleeve extending between the bottom portion 22 and the open top 24 is sufficient that the sleeve extends a slight distance above ground level 18 when the post 16 is in the ground.
Collar 14 defines a length of collar material that surrounds post 16 immediately above ground level 18 and which is attached to the post and encircles the open top of sleeve 12 to prevent moisture and debris from entering the open top of the sleeve. As detailed below, the collar 14 is designed to allow evaporation of moisture from the interior of the sleeve 12, prevent UV radiation from impinging on the sleeve 12, and prevent water and other debris from entering the sleeve. As shown in
Beginning with the lowermost edge 30 of collar 14, which generally rests on or adjacent to the surface of ground 18 in the assembled apparatus (
For reference purposes, the exterior surface of collar 14 is identified in the drawings with reference number 46—the exterior surface 46 is exposed to the elements when the collar is in place around a post 16. The opposite surface of collar 14, that is, the surface that faces post 16 is identified as interior surface 48. An upwardly and inwardly sloping lip 50 is formed on interior surface 48 of collar 14 below and adjacent to the junction between the vertical sidewall section 32 and the sloping edge section 34. Plural vent openings 52 are formed in collar 14 above lip 50 and below the junction between the vertical sidewall section 32 and the sloping edge section 34.
Collar 14 is formed from a flexible, malleable material that is waterproof and resistant to degradation from ultraviolet radiation. A thermoplastic elastomer sold under the brand name SANTOPRENE is one material that has found to exhibit good properties for use in collar 14. While a variety of colors may be used for collar 14, the preferred color is black. The collar is provided in an extruded roll and the collar is cut to an appropriate length by the installer; the lineal length of the collar 14 as used with a post 16 is the same as or slightly greater than the circumference of the post where the collar surrounds the post just above the level of ground 18, as shown in
With specific reference to
Returning to
The circumference of post 12 immediately above the level of ground 18 is then measured and a length of collar 14 is cut to the length of the circumference, or slightly greater. This is best shown in
As an alternative method of attaching collar 14 to post 16, the opposite ends 56 and 58 of the collar may be tacked or stapled to the underlying post and the fastener 60 may be omitted.
As best illustrated in
Immediately below edge 38, the collar 14 diverges outwardly away from post 16 at sloping edge section 34. Again as best seen in
Most wooden posts have some residual moisture that wicks away from the post and evaporates over time. The passageway 66 thus allows water vapor that evaporates from the post, even in the portions of the post below the level of ground 18 to escape from the collar. External water such as rain and irrigation water cannot enter space 62 through holes 52 because lip 50 is sloped upwardly (relative to the ground plane) and blocks water from entering the space. Moreover, the lip 50 effectively blocks UV radiation from hitting sleeve 12. This prevents degradation of the sleeve over extended periods of time.
The combination of sleeve 12 and collar 14 defines an effective apparatus and method for enhancing the life of in-ground wood. It will be appreciated by those of skill in the art that a variety of structural changes may be made to the sleeve and collar relative to the embodiments disclosed above without departing from the nature and scope of the invention.
While the present invention has been described in terms of preferred and illustrated embodiments, it will be appreciated by those of ordinary skill that the spirit and scope of the invention is not limited to those embodiments, but extend to the various modifications and equivalents as defined in the appended claims.
