b'( Some Criteria Identified with " Vegetative Roofs Sustainability" L us look at s e ofsolutions to meet some or all of theseWhen people think of "green roofing," they think of rooftop gardens or etom the proposed criteria,comm tthe "pros""cons"each."vegetative roofs." Incases they arerect, but "green roofing" techanden onandofsomecornically meansything that is environmentally-friendly. For our purposes anRoofing Products that Incorporate Recycled Materialsthe s is vegetative-covered roofs. ubject Except for metal, there is not much recycling currently going on in theThis category is faricated to discuss h edeserves an artitoo compl er and roofingSome ofn high-end shing products that resemblecle of its own. What we can say istare growing in d are industry.theew,letha theyemand and s tetilerate recycled rubber and plastic materials. Theofbeing mandated by some governing bodies. T problem is they are o la orincorpo useheutrecycled asphaltd insulation have been tried,not with much success.racing thegroups that produce the building codes thatulate the an butcodifyingregUntil there is achgerrt to use recycledials, the "cons ofrest of roofing. mu lar effo materrecycling m roofing materials will not readily reveal th .The issue of sustainability is an importantandll be e more ostemselves onewi venso If in the future.you are interested in offering vegetative roofing, realize you Products that Reduce or Eliminate Hazardous Emissionsmay void manufacturers\' warranties or beiblethe safety held respons forand There has been a lot of work lately onloping new roofing productsperformance of landscapers or other c ctors. deve ontrathat a ironm iendly. In the single-ply industry, much work has re env entally-frbeen done on the p nuse ofadhesives. Work hasMetal Roofing roductio andwater-based been doneyears onlow-fuming roofing pitch and asphalt. Latex-typeMetalroofingis ever-increasinginitspopularity,becausethereare for lksprodu tsmero greenrodu t.veral coatings and cau are now being introduced as eco-friendlyc fornu us "pros" as aroofing p c It fits se of the criteria for the roofing industry.sustainability.can be manufactured from recycled materialsd itlikely Itan is H r, water-based a esives, coatings a caulks are in some casesto have an extended service life. Italm t onedrecyclable oweve dh ndisos hundre percent more expensive and more sensitive to te erature fluctuations than tradi after it has completed its service cycle. It can be highly refle ive.emismp ct No tionalIn some cases they just don\'t work as well. It isio lesions are createdits in llation. products.quest nab instawhether or not the "green roofing com nity"ever accept the use of coalMetal roofing\'s biggest "con" is c An installed m roof is much mu willost.etal te theroofitar pitch for roofing, as they barely tolera use of asphaltng today.more expensive than a traditional conventional roof. They may be noisy in some c s. A ugh long-lasting,ntimecome they onfiguration ltho whe thedoes Photovoltaic Roof Systems and Panelsa mo a rrere expensive to removendeplace. Pho volta roof systems produce direct currentfrom the use to icelectricity of solar cells either incorporated into the actual roof, or produced fromlarHighly Reflective Roofing sopanels mounted on the roof. The new p ts that incorporate photo Highlyive roofs areor coated with a re areroduc reflect either whitereflective coating, thearela ersilveretalOne voltaic cells inshingles, and therep ns to do the same in oth or by their nature are reflective such as am roof.big "pro" for materials. Photovoltaichave been used for yearsroof is theusing alective coating is that you may use themwatertight "flar or panelsand theref on logical place to gather the m sunlight.low-slopedroofingsystems thatmaynot easily accommodate a steepost The biggest "con" of p syste is the amount of equipmentsloped water shedding system like your typical metal roof. Accordingthe hotovoltaicmsto needed toconve thedirect c touseablecurrent.TheEPA, whitereflect ultraviolet rays save about 40% of the energy rturrentalternatingroofs that expense of roofing materials that have cells inmaterials requires s required forling.that comply w E Star certification reduce theub coo Roofsithnergy akefeasible ooling stantial subsidies to m their use even. Problems may emergepeak c demandby about 15% and anexistingroof\'slifemay be from u of largeof rooftop equipment, a particularly thene enhanced by the use of a,-reflective coaseamountsndpe quality high ting. trations they require.Thereaof cons" with regard to these highly arecouplereflective roofs. S white membranes do notas long acycletheir b komehavelifeaslac relaProducts for "Green Roofing"tives. The energy savings are always related toB dings must also cooling.uilThere a aroofing systems and specialized products that havebe heated, a in areas where the heating degree days exceed the coorenumber ofndling revi ost high sulationbette solutbeen developed to meet this demand. Let\'sew some of the mdegree days the addition of in is arion than highly reflecprofile of these "green" o tive roofing -and in snow country it may even cause some problems. Sptions.ome coatings m be criticized forirled solven . aythe volati hy rocarbontsIf youinterested in n out more about "green" building arefi dingstandards, visit.org, www.nahb. ,www.greenglobes.com. www.usgbc org or Kurt Baumgartnerchiefadvi for the Midwestfing ConistechnicalsorRootractors Association. \'11'