Road structure – process – or apparatus – Process – Handling or treating preformed modular unit
Reexamination Certificate
1997-02-07
2002-12-10
Hartmann, Gary S. (Department: 3671)
Road structure, process, or apparatus
Process
Handling or treating preformed modular unit
C052S746100, C052S746110
Reexamination Certificate
active
06491471
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
REFERENCE TO A MICROFICHE APPENDIX
Not Applicable.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to composition and methods useful for protecting new and existing sheeting material used for low slope roofing. More particularly the sheeting material comprised of ethylene-propylene-deine-monomer, referred to herein as EPDM. Even more particularly, the invention relates to such a walkway protection system which eliminates the need for heavier and thicker materials that are neither waterproof in their design nor installed in a watertight condition. The present invention provides an improved walkway protection system for new or existing EPDM roof sheeting material in areas subject to damage from regular maintenance work on serviceable rooftop Heating, Ventilating, and Air Conditioning (HVAC) equipment. The protective material is installed at access points to the roof, as well as to, around, and between serviceable HVAC equipment. These areas are subjected to either excessive amounts of foot traffic from trades conducting service work or sharp metal edges from access panel doors, tools, and discarded rooftop equipment parts.
2. Background Information
EPDM sheeting material has been used as single ply roofing membrane on low slope commercial and industrial buildings for a number of years. During that time, the majority of the EPDM membrane used as roofing material has been unreinforced and either 0.045″ or 0.060″ thick. Non-reinforced EPDM roofing in these thicknesses is resistant to degradation and damage from a variety of natural, as well as man-made, causes. However, even though non-reinforced EPDM has proven to be a reliable roofing material, non-reinforced EPDM roof sheeting that is 0.045″ or 0.60″ thick is susceptible to puncture and/or cuts in areas subjected to regular access by maintenance personnel. Punctures and cuts in the non-reinforced EPDM can be caused by hand tools, metal access panels on rooftop HVAC equipment, sharp debris, discarded HVAC parts, and regular foot traffic.
EPDM roof sheeting material has several attachment methods. The EPDM may be adhered directly to a suitable substrate, mechanically fastened over a suitable substrate or loose-laid and ballasted with stone ballast. The majority of EPDM roofing is loose-laid and ballasted. On exposed EPDM systems such as adhered and mechanically anchored, cuts and punctures are relatively easy to find and repair. However, on a stone ballasted system, a great deal of time and effort can be expended by laborers removing stones to discover a leak. In addition, a small puncture or cut may be obscured by the dirt that tends to collect below the stones over many years of exposure to airborne dirt and contaminants.
Various types of protective walkway systems are provided, as well as methods of installing the same, in order to provide a protective layer between the sources of cuts and punctures and the roofing membrane. One popular method is using concrete pavers, however, the concrete pavers have several disadvantages. First, the concrete pavers must be installed with a protective cushion layer of loose EPDM, or other suitable cushion material, between the concrete paver and the EPDM roof. Second, the concrete pavers do not have the same lifespan as the EPDM membrane. After twelve to fifteen years, the pavers spall, fracture, and create another source of membrane puncture. Third, if the concrete pavers are installed over field or flashing seams, then additional measures are required to protect the seam from the damp conditions that are created under the paver. Fourth, concrete pavers are heavy (approximately eighty pounds each) for laborers to lift and gently place on to the membrane. Fifth, responsible EPDM roofing manufacturers do not permit concrete pavers on mechanically anchored EPDM roofing systems because the systems billow and the pavers could become airborne during a wind event. Sixth, concrete pavers are usually permitted on adhered EPDM systems, however, they add weight to the roof and would still require a loose cushion layer between the paver and the membrane roof.
Additional current art to avoid puncture of the EPDM membrane in high traffic areas have several disadvantages. One material in current art is a square rubber mat that is spot adhered to the EPDM. The square mats are installed with gaps between the squares to facilitate drainage of water that collects on the roof surface. In addition, the mats are not waterproof themselves and are not installed in a waterproof condition. Current installation techniques for these square mats call for the mat to be adhered to the EPDM with either contact cement or peel and stick tape products. A second material consist of grounded-up rubber fragments that are bound together to form a roll. The roll of material is installed continuous, however, the material itself is not waterproof. In addition, the roll is not installed in a waterproof condition. The installation techniques would be similar to those described for the square mat. With either of these materials, a leak that occurs under the mat or roll is difficult to detect. A roof repair technician that is searching for a leak would not necessarily look under the current art walkway as these materials are supposed to protect the EPDM from puncture and damage.
In an effort to increase puncture resistance, as well as enhance other performance characteristics of the product, EPDM roofing manufacturers began manufacturing scrim reinforced EPDM. The scrim reinforced EPDM roof membrane has become a niche product and is used mainly in mechanically anchored EPDM roofing systems. This product is rarely used in either fully adhered or ballast EPDM roofing systems.
BRIEF SUMMARY OF THE INVENTION
Objectives of the invention include providing an improved continuous puncture resistant protective walkway system that is installed in a watertight condition and method of forming the same which eliminates the need for stone ballast around serviceable rooftop HVAC units, pathways between serviceable rooftop HVAC units, and pathways between roof access points and serviceable rooftop HVAC units.
A still further objective of the invention is to provides a continuous puncture resistant protective walkway system that is installed in a watertight condition which uses existing adhesives and caulking sealant materials which have been field tested and are compatible with each other and with the waterproof membrane, thereby eliminating possible harmful interaction between the various materials and the roofing membrane.
A still further objective of the invention is to provides a continuous puncture resistant protective walkway system that is installed in a watertight condition which can be performed easily by roofing personnel without requiring expensive equipment and skillful operations, and which can be accomplished in a relatively short period of time and with a minimum amount of materials, thereby reducing the cost of the roofing installation while providing an enhanced walkway system.
These objectives and advantages are further achieved by the improved method of the invention, the general nature of which may be stated as including a method of installing a continuous puncture resistant protective walkway system over new or existing waterproof roofing membrane including the steps of installing a layer of reinforced EPDM over new or existing EPDM; mechanically anchoring the new or existing EPDM with a metal, plastic, or reinforced EPDM strip and fasteners (Ballast system only); adhesively securing together the new reinforced EPDM to the new or existing non-reinforced EPDM using existing adhesive materials; and applying a bead of existing caulking sealant over the seam edge.
REFERENCES:
patent: 4284366 (1981-08-01), Lucik
patent: 4684288 (1987-08-01), Chaps
patent: 4932171 (1990-06-01), Beattie
patent: 5322724 (1994-06-01), Levens
patent: 5496615 (1996-03-01
Browning Clifford W.
Hartmann Gary S.
Woodard Emhardt Naughton Moriarty & McNett
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