July 1, 2004

10 Min Read
Get Into The Ooze

Get Into The Ooze

Preventing building deterioration through the use of coatingsand sealants

By Elaine Foxwell

Whether the culprit is UV light, the corrosive effects ofclimatic pollution, or oxidation from snow and rain, self-storage buildingsdegenerate over time from exposure, resulting in a loss of value. To literallyshield your investment, experts recommend a vital maintenance plan involving theuse of sealants and coatings.

In a report on the North Americansealants market by Frost & Sullivan, a global market-research company, asealant is defined as a liquid, paste or foam material that, when applied toa joint or orifice, forms a tight seal against liquids or gases. The reportidentifies nine major and nine sub-classified sealants. Each has its owncomposition and properties and is effective for different applications.

With so many types of sealants, facility owners may be at aloss to decide which is best for particular repairs. Storage buildings, most ofwhich are metal, expand and contract. To be effective, sealants need to beelastomeric as well as have structural strength. But why and how do sealantsfail?

Water ingress will undoubtedly be the major cause ofstructural degradation of a building, not to mention the No. 1 cause ofconsequential damage claims for ruined contents of occupied spaces, says Lester Hensley, president of Emseal Joint Systems Ltd. inWestborough, Mass. Emseal supplies preformed foam and mechanical expansionjoints.

Roof-Coating Systems

The majority of existing commercial roofs are metal, built-up,single-ply membranes and polyurethane foam. There are different methods ofrepairing and maintaining these substrates, and it is important building ownersconsult someone experienced with their specific roof, says Dave Kessler,director of operations for Uniflex Roofing Systems LLC. The Medina, Ohio-basedcompany manufactures a complete line of roof coatings and accessory itemsdesigned to waterproof existing buildings.

Aluminum and elastomeric are the two primary coating systemsspecified for metal. Facility owners should ask the contractor or manufacturerfor references specific to their substrates, as larger problems can be createdif incorrect materials and methods are used for repair. Whoever works on the roof should have the proper insurance,equipment and experience in the installation of materials. The product is only as good as the application. If the prepwork is not done properly, a roof failure is imminent, Kessler says.

Roof-coating systems range in cost from $1 to $2 per squarefoot, depending on the existing condition of the roof and amount of work needed.Before hiring an applicator, building owners should do some basic research.Kessler says to consider how long a company has been in business; its history ofexperience and references with your type of roof substrate; whether it hasproper insurance with a rated insurance carrier; estimated length of projecttime; and type of warranty, if offered.

A high-quality roof-coating system includes a biodegradablecleaner to prepare the surface metal, industrial-grade caulk for repairs atseams and protrusions, and an elastomeric coating made from 100 percent acrylicresins, says Clint Whitsett of United Coatings, a Greenacres,Wash.-based manufacturer of water-based, 100 percent acrylic elastomer. Theadded benefit of an acrylic roof coating is it will remain flexible, allowingthe metal to expand and contract with fluctuations in temperature.

Application.

Prior to theapplication of a coating, the roof must be thoroughly cleaned, all mechanicalfasteners checked for integrity; and rust removed, says Whitsett. Theelastomeric basecoat should be applied at a minimum of 1 gallon per 100 squarefeet. After the basecoat is dry, a topcoat is applied, also at a minimum of 1gallon per 100 square feet.

The coating should be applied by airless spray, using amultipass technique to ensure even application to all sides of the metal-panelcorrugation. It is important to apply coating into crimped or pre-sealed vertical(side-lap) seams that have not been detailed. The minimum basecoat/topcoatdry-film thickness required at any location is 15 mils, generally for afive-year product warranty. For extended coverage periods, additional coats andheavier film builds will be required, Whitsett says.

A good roof coating will cover an average of 60 to 100 squarefeet per gallon for the first coat and 100 to 150 square feet per gallon for thesecond. Walls and doors with good pigmented direct-to-metal (DTM) latex willaverage 250 to 350 square feet per gallon. Some surfaces may need two coats forcomplete coverage. Good roof sealants should last five to eight years;exceptional-quality products can last as long as 15 years. Good-quality DTMpaint will last three to five years.

Maintenance and Inspections.

RickDodge, vice president of sales and operations for Rib-Roof Metals Inc., aRossville, Tenn.-based manufacturer of roofing and building systems for theself-storage industry, suggests regularly inspecting roofs for cracks andbubbles in the sealants, particularly in exposed areas. Though Galvalume-coatedsteel has become the major material used in metal roofing, roofs still sustaindamage from the elements. Regular maintenance is required to keep themfunctional and attractive.

William Rice, president and CEO of Vivilon Coatings Inc. in Miami, Fla., a manufacturer of surface-restoration andprotection coatings, advises implementing a bimonthly inspection program forsigns of early paint aging, and correcting those areas by proper reapplicationof the appropriate coating. Coating and sealant touch-ups are simple and can bedone by in-house staff, though a paint contractor can be retained to do thework.

Dirt is one of the most overlooked enemies of paint, Rice says. It cant be overemphasized that a monthlysurface washing can easily double the life expectancy of almost any qualityproduct. Brushing with a good neutral-pH cleaner and rinse would be preferable;but even a quick hose down would greatly increase the durability of any paint.Nothing can be done about UV radiation, or extremes of hot or cold; but cleaningoff surface grime is quick, easy and inexpensive, he says.

In addition to regular maintenance inspections in thespring and fall, it would be in the owners best interest to inspect roofsafter storms or heavy winds to make sure there is no weather-related damage,advises Kessler.

Heavy snow loads and ice removal can cause damage such asgouged or split panels, loose fasteners, split seams, etc., warns RickThomas, marketing manager for Binghamton, N.Y.-based, Insulating Coatings Corp.,a manufacturer of roof-coating systems for metal roofs. If rust or corrosionis present, a rust primer should be applied prior to the waterproofing and afterthe roof is completely power-washed, he says.

Floor Coatings

Storage owners may ask, Why should I seal my concretefloors? Concrete is a porous and unique building material. In its unsealed state, concrete absorbs moisture and liquidspills as well as collects dust in its pores, which reside below the surface,says Don Crawford, president of Chemisol Resources Group Inc. in Glendale, Ariz.The company specializes in sealing and maintenance of concrete surfaces andmanufactures a water-based acrylic sealant.

As the self-storage industry has evolved, it has increasedits level of services and sophistication. Customers are attracted to clean, bright, well-maintainedfacilities, Crawford says. A clean floor reduces dust and helps maintainthis image. Sweeping and mopping helps, but is extremely difficult to do on anunsealed concrete floor because of the drag created by the surface texture.

A quality sealant may average three to six months betweenapplications, depending on wear and level of floor maintenance, Crawford says.Wear is determined by a number of factors, such as facility traffic, performanceof intermittent sweeping and damp mopping, and destructive use, such asscratches and scrapes. Crawford recommends using a regular cleaning service,with the frequency determined by the type of flooring, facility traffic anddesired level of appearance. Owners should use a service that specializes in thesealing and maintenance of concrete surfaces. Between services, owners can use apH-neutral cleaner for daily maintenance.

Protecting Doors and Buildings

Teresa Sedmak, president of Everbrite Inc., a Reno, Nev.-basedmanufacturer of a protective coating that refinishes faded and dull metalbuildings, advises owners to check metal surfaces for fading, oxidation andcorrosion at least once a year. An easy way to check the degree of fading andloss of gloss is to observe an area that is wet, she says. Use a wetfinger, cloth or sponge to touch the area. If there is a noticeable differencein color or gloss, the metal should be sealed and protected before it getsworse. Once fading begins, deterioration will accelerate rapidly and becomemore labor-intensive and expensive to fix.

Check for salt corrosion by running your hand over the topribs of a roll-up door on the north or east side of the facility, where themoist salt air sits for a longer time before it dries, Sedmak says. If thereis corrosion, the surface will be rough or bumpy. In this instance, application of a coating will fix theproblem. On the other hand, acidrain damage can only be prevented by sealing the metal. Once acid rain etches a surface,there is nothing that can be done to refinish it.

Application.

To refinish and protecta metal surface, first remove all chalk, grime, alkaline salts or any othercontaminants. Purchase a coating that can be sprayed or wiped on and can berepaired if a mistake is made, Sedmak says. If care is taken to follow alldirections, properly prepare the surface and apply the coating, self-applicationcan have good results. She does, however, suggest using a professionalapplicator, as it will be experienced with storage facilities, and know how tokeep water out of the units and solve the variety of cleaning and applicationchallenges roll-up doors can present.

A gallon of quality clear coating should cover about 20 to 24large roll-up doors (roughly 1,200 square feet). Owners considering repaintingvs. coating surfaces should consider cost on a per-square-foot basis, saysSedmak. While a gallon of paint is less expensive than a quality clear coating,the cost per square foot may be much higher because of coverage. Paint will alsostart to fade in a year, but a clear coat should not fade for many years. A goodcost for materials is about 15 to 20 cents per square foot, Sedmak says.

Upkeep.

A clear-coat finish can berenewed every five to 10 years. Make sure the coating is self-annealing andwill self-blend so the first coat does not need to be stripped off, Sedmaksays. Also look for a coating that will expand and contract with the metal so itwill not crack and peel. Avoid thick or very hard coatings like lacquer orpaint, which are not flexible. Once buildings are sealed and protected, they canbe simply washed with water. In the case of more difficult stains, a mild,neutral-pH soap solution can be used.

Final Words

Most industries underestimate the importance of sealants in the lifetime performance of their structures, Hensley says. While it is possible to ensure long-term waterproofing for as little as .5 percent of the average cost of a building, owners and builders tend to consider sealants an accessory to be purchased for the lowest possible cost. Consequently, the best cure is an ounce of prevention. In other words, the costs of remediation of failed sealants will significantly outweigh the costs of using a high-performance sealant up front, he concludes.

Last year, China used 55 percent of the worlds cement and36 percent of its steel, according to an April article in TheIndependent, a U.K. newspaper. This consumption hasresulted in skyrocketing prices for steel materials, including self-storagebuilding components. Now more than ever, maintenance of your metal structures makesmore economic sense than replacing them.

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