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2018ROOFINGSYSTEMSGuide To Com m er cial Roofing System s: Pr os and Cons
2SENTRY ROOF SERVICES ROOFING SYSTEMSGui de To Com m erci al Roofi ng System s:Pros and ConsWith all the different types of commercial roofingsystems available today, how do you decide whichis the best for your building?Your roof is a significant investment and your property's firstline of defense against the elements. Installing a new roof ormanaging the one you have is not something to take lightly. It'simportant to think about your unique building, priorities, usage,goals, and finances as you weigh your options with your roofingprofessional. Each system has its pros and cons but, fortunately,mostly pros ? roofing systems have come a long way.Th is over view of t oday 's m ost popu lar com m er cial r oof in gsyst em s in clu des:-TPOEPDMPVCMETALASPHALTSLATE AND TILEVEGETATIVE
Gu ide t o Com m er cial Roof in g Syst em sTPO COMMERCIAL ROOFSTh er m oplast ic Polyolef in (TPO) com m er cial r oof s are themost popular commercial roofs in use today. First installed inthe late 1980?s, a TPO commercial roof is a flexible, single-plymembrane that is either fully adhered (glued down) ormechanically attached. It's smooth, made of a polymer/fillerblend (a rubber compound) and is usually white.TPO membranes are available in several different thicknessesand some models include a fleece backing for installation overabrasive surfaces. TPO technology continues to improve ?some new TPO systems are warrantied for up to 35 years.Th e Pr osTPO commercial roofs are reflective so they keep your buildingcooler during the summer, which can decrease your energy useand carbon emissions. The flexible quality allows it to be easilyshaped around the details of any roof the roof and to maintainits integrity during building movement. Other benefits include:-Easy to installNon-toxic3
4SENTRY ROOF SERVICESDuri ng i nstallati on,membranes areheat-weldedtogether at anextremely hi ghtemperature tocreate a fused seam.Fused seams are upto si x ti messtronger than gluedseams.- ROOFING SYSTEMSEconomicalSustainable (membranes can be recycled)Long-lasting performanceDuring installation, membranes are heat-welded together atan extremely high temperature to create a fused seam. Fusedseams are up to six times stronger than glued seams yet alsoflexible, which contributes to their longer-lasting performance.Th e Con sSince it's a single-ply membrane, TPO is more vulnerable topunctures and abuse from rooftop activity, which puts theunderlying layers at risk. Inexpensive TPO can be especiallyvulnerable. If there?s a puncture in an area where water ponds,you could experience a severe leak. Newer, improvedmaterials, such as thicker membranes and specialized workpads, alleviate a lot of the drawbacks. However, TPO will stillshrink over time.War r an t iesNew TPO roofs come with a variety of warranty configurationsranging from 10 to 35 years.
5Gu ide t o Com m er cial Roof in g Syst em sEPDM COMMERCIAL ROOFSEt h ylen e Pr opylen e Dien e Ter polym er (EPDM ) com m er cialr oof s are highly resilient and popular for low-slope roofs,although they're being installed less frequently lately. They?remade of a durable synthetic rubber membrane that typicallyconsists of two main ingredients ? ethylene and propylene. Themembrane is either black or white, available in differentthicknesses, and comes in widths ranging from ten to 50 feet.An EPDM system may be fully adhered (glued), attachedmechanically, or ballasted (held in place by gravel or anotherheavy material). The seams are sealed with a liquid adhesive orspecialty tape.Th e Pr osEPDM is resilient ? these systems can last 30 years whenproperly installed and maintained. They are also:-Available in ultra-wide sheetsResistant to thermal shock ? effective in most climatesResistant to hail damageAbility to withstand damage from UV radiationAdaptive to structural movementCan be recycled when re-roofingTh e Con sEPDM roofing systems require clean, dry conditions to properlyseal the seams or they may leak, and should not be installed indirect contact with asphalt products. Other chemical reactionsbetween materials and adhesives can result in blistering frominsufficient adhesive curing. Black EPDM roofs also absorb heat.War r an t iesWarranty options for EPDM roofing systems range from 10 to 30years depending on the thickness of materials used and themethods used for the flashing details. You can also purchaseriders covering high wind, hail, and punctures.An EPDM systemmay be fully adhered(glued), attachedmechanically, orballasted (held inplace by gravel oranother heavymaterial). The seamsare sealed with aliquid adhesive orspecialty tape.
6SENTRY ROOF SERVICESPVC roofs areexcellent at resi sti ngrooftop chemi cals,oi ls, greases, andi ndustri albyproducts ? thi s i sthei r mostdi sti ngui shi ngfeature whencompared to othersi ngle-plycommerci al roofi ngsystems. ROOFING SYSTEMSPVC COMMERCIAL ROOFSPVC (polyvin yl ch lor ide) com m er cial r oof s are the originalheat-welded single-ply roofing systems ? they' been aroundfor more than 50 years. They're durable, flexible, and eitherfully adhered or mechanically fastened. PVC roofs are excellentat resisting rooftop chemicals, oils, greases, and industrialbyproducts ? this is their most distinguishing feature whencompared to other single-ply commercial roofing systems.Th e Pr osFor buildings like restaurants with grease traps on the roof,PVC is preferred choice. PVC is also:-Long-lasting ? up to 35 years or longerFire resistantFungi and bacteria resistantAvailable in custom colorsPVC roofs are also highly reflective and can be easily cleaned.Th e Con sLike TPO roofs, PVC will shrink over time despite significantimprovements in recent years. In heat aging tests, PVC roofsdon't do as well as newer TPO formulations. PVC is alsoincompatible with asphalt so when re-roofing you must eithercompletely remove asphalt products or install a separatorsheet to prevent premature aging.War r an t iesFive to 30-year warranties are available, as are warranties forhigh wind and hail.
Gu ide t o Com m er cial Roof in g Syst em sMETAL COMMERCIALROOFSM et al com m er cial r oof s are insulating, attractive, and canbe very durable. They?re made from a variety of metals ?including galvanized steel (the most popular), aluminum, zinc,copper, and stainless steel ? either alone or in combination,and are covered with a coating to protect against the sun,weather, and corrosion.The existing roof slope along with the roof penetrations andarchitectural features impact metal roof design options. Metalroofs generally require a minimum 1? in 12? fall to adequatelyperform well. They can be installed over a continuoussubstrate (architectural panel) or open framing (structuralpanel). Roof insulation can be added directly below the roofpanels or in attic space to provide thermal resistance.Light gauge metal framing packages are available totransform an existing flat roof to a sloped substrate for a newmetal roofing system.Th e Pr osProperly designed and installed metal roofing systems canlast up to 50 years. When combined with substrate insulation,they easily comply with today?s more stringent energy coderequirements.7
8SENTRY ROOF SERVICES ROOFING SYSTEMSOther advantages include:M etal roofs arealso better for theenvi ronmentbecause most aremade fromrecycledmateri als, whi chmeans fewer newmateri als weresourced to createmetal commerci alroofs.-Lower life-cycle costsMinimal maintenanceVast array of systems and finishesReduced carbon footprintMetal roofs are also easy on the environment because mostare made from recycled materials and most metal roofs can berecycled again as well. Light-colored metal roofs reflect heat.Th e Con sProblems usually relate to the combination of materials anddesign or the quality of the installation. Temperaturesfluctuations can lead to oil canning, or bending, over time withcertain panel widths. And if a metal roof includes a fastenersystem that?s exposed, you could start seeing some leaks injust seven to ten years. However, good planning and awillingness to add to the complexity of the installation canprevent these problems and others.It?s also more difficult to walk on a metal roof and can be moredangerous ? metal roof can be slippery. If your roof has a lotof equipment or penetrations like vents and skylights, it maynot be a good candidate for a metal roof.War r an t iesMetal roofing systems can be warranted from five to 30 yearsand cover materials including panels, underlayment, and evenpaint finish.
9Gu ide t o Com m er cial Roof in g Syst em sASPHALT COMMERCIALROOFSAsph alt com m er cial r oof s have been popular historicallybecause they work well and are very durable. Typically used onlow-slope structures, asphalt roofs consist of several layers ? aweather-proofing layer, one or more reinforcement layers, anda protective surface layer.Asphalt commercial roofs fit two broad categories:--Bu ilt -Up Roof in g (BUR) ? Layers can include a vaporretarder, insulation, membrane (made of layeredcomponents adhered and waterproofed with asphalt)and surfacing material, all assembled at the job site.M odif ied Bit u m en Syst em s (M BS) ? A modifiedpolymer adds strength to the system, which isassembled at the factory and can be installed in a singleply or in multiple plies similar to BUR. The MBS productoften has a factory applied surfacing.Other options for asphalt commercial roofs include integratingmaterials such as asphalt and gravel surfacing, fiberglass,aluminum, copper, minerals, and different grades of bitumen.Th e Pr osAsphalt roofing systems provide exceptional performance andare known for being a moderate-cost but durable option. Theyalso offer:-Multi-layer protectionUV and fire protectionUplift protectionEasy maintenanceMany options and materials to choose fromBoth categories of asphalt roofing system offer their ownadvantages.BUR offers especially good water resistance by nature of itsredundancy, uplift resistance, and resistance to daily wear andtear from foot traffic. Its strong insular qualities can also makeyour building more energy efficient. MBS offers increasedTypically used onlow-slope structures,asphalt roofs consistof several layers ? aweather-proofinglayer, one or morereinforcementlayers, and aprotective surfacelayer.
10SENTRY ROOF SERVICES ROOFING SYSTEMSstrength and flexibility, application method options, and workswell in all climates.Th e Con sAsphalt commercial roofs aren?t right for every building.Installation can be tricky to ensure proper performance, andspecialized equipment and expertise are required.BUR?s are typically constructed on the roof surface with hotbitumen (asphalt) at or above 400 degrees. The crew must getthe hot bitumen to the rooftop and install it at the applicationsite before it cools. Today, cold adhesives are often used in lieuof hot asphalt, and some MBS systems use open-flame heatwelding to adhere asphalt that was pre-applied at the factory.If a roofing system requires hot asphalt or an open flame, yourcontractor will need to create a site-specific safety plan.War r an t iesWarranties are available for 10 to 25 years, depending on thesystem, and coverage limits vary from manufacturer tomanufacturer.
Gu ide t o Com m er cial Roof in g Syst em sSLATE AND TILECOMMERCIAL ROOFSSlat e an d t ile com m er cial r oof s are often considered the bestavailable ? life expectancy is up to 150 years for slate and 100years for tile.--Nat u r al slat e an d t ile ? Slate shingles are quarried frommines and clay tiles are fired, as with earthenware.Traditional slate comes in many varieties of colors,thicknesses, and grains. Clay tiles vary in finishes andcolor, with classic terracotta red being the most popular.Syn t h et ic m at er ials ? Synthetic materials look, installand perform as natural materials but cost less. They alsolast about half as long (50 years). Synthetic (faux) slateshingles are made from composite materials (plastic orrubber) so they don?t break easily, and synthetic tiles andfaux cedar shakes are made from concrete or a polymercomposite.Shingles and tiles are hung in rows using nails attached to aframework underneath. The shingles overlap each other whichhides the nails and allows rainwater to flow over the top.Th e Pr osSlate and tile roofing systems have worked well for more than4,500 years and provide excellent value even though they?reexpensive to install. The materials are also sustainable. Other11
12SENTRY ROOF SERVICES ROOFING SYSTEMSbenefits include:Slate shi ngles arefragi le duri ngi nstallati on andi nstallers must beable to dri ve nai lsdown to 1/8 i nchabove the shi nglebut no fur ther.-High-performing, even during natural disastersLow maintenanceEnergy efficient ? some shingles are Energy Starrated and can earn LEED pointsFire and pest resistantCan be cleaned and reusedRecyclable ? some clay tiles are made with recycledpost-industrial materialsCan increase curb appeal and property valueTh e Con sSlate shingles are fragile during installation and installersmust be able to drive nails down to 1/8 inch above theshingle but no further. If a shingle is hit with a hammer, thehairline crack that results will cause the shingle to fall apartwithin a few years.Artistic skill is also needed to create a shingle pattern thatlooks random and natural. Other cons include:-Cost (initially)Finding experienced installation specialistsTakes longer to repair and replace the roofTechnician access for maintenance duties can bechallengingCracked shingles when walk boards or specializedrigging is not used when servicing the buildingCrews also need to know how to install Heritage copperguttering systems, a 1/2 round gutter system that works inconjunction with slate and tile roofs and last just as long.War r an t iesWarranties for slate and tile roofs are usually 50, 75, oreven 100 years. Sometimes a labor warranty of 20 years orlifetime labor is included as well. Most synthetic slate roofsand concrete tile roofs have 50-year warranties.
13Gu ide t o Com m er cial Roof in g Syst em sVEGETATIVE COMMERCIALROOFSVeget at ive com m er cial r oof s have a living vegetative (plant)layer on top of a conventional flat or sloping roof. A vegetativeroofing system also includes components like filters, adrainage system, and sometimes an irrigation system.Modular systems include pre-planted trays that can be moved.Built-in-place systems are installed directly on the roof andcan be lightweight or as heavy as 80-150 pounds per squarefoot, depending on the soil depth and types of plantings.Th e Pr os-Increased energy efficiency ? plants keep roofs coolerin summer and warmer in winterHigher R-value (thermal resistance)Improved storm water managementProtects roof membrane so membrane last longerReduces airborne contaminants and urban heat islandAdds visual interestTh e Con s-Can cost twice as much to installLandscaping-type maintenance may be requiredCan be hard to find roof leaks under built-in-placesystemsCan lead to unwanted wildlife and insectsCan be heavyWar r an t iesWarranties for vegetative roofs vary greatly, with single-sourcewarranty will typically include the cost of removing theplantings to find the source of a roof leak.13A vegetative roofingsystem also includescomponents li kefilters, a drainagesystem, andsometimes anirrigation system.
Gu ide t o Com m er cial Roof in g Syst em sTHE BEST ROOF FOR YOURPROPERTYWh et h er it ?s a sin gle-ply r oof on an in du st r ial bu ildin g, aslat e r oof on a h ist or ic ch u r ch , or an yt h in g in bet w een ,u n der st an din g you r opt ion s f or r e-r oof in g is t h e placet o st ar t .An informed decision is bestSentry Roof Services believes your roof is an asset that shouldbe managed like your other business assets. Choosing the bestroofing system for your needs and having it installed by anexperienced contractor with skilled technicians is job one, butthat's only part of the picture.Even new roofs need regular maintenance to keep themperforming at their best. A roofing technician should be presentwhen you change or add rooftop equipment , and if you decideto renovate, add onto your building, or make other changes thatcould potentially impact your building envelope, an experiencedroofing contractor can provide valuable insight.If you have questions about any type of commercial roofingsystem, please contact Sentry Roof Services at 687-301-5555 orinfo@sentryroof.com. We have 35 years of experience, work onsome of metro Atlanta?s most notable properties, and are proudto have customer relationships that span decades.Please visit sen t r yr oof .com or ou r blog f or m or ein f or m at ion . Sentry Roof Services photos: Cover: Solace on Peachtree; page 3: Bass Lofts;pages 4: Concourse E at Hartfield-Jackson Atlanta International Airport; page 6:Riverdale Town Centre; page 7: Marietta High School; page 8: CarMax in TinleyPark, IL; page 10: Peachtree Presbyterian Church; page 11: Piedmont Driving ClubPhoto credits: Page 13: Groffs Family Funeral Home in Lancaster, PA (photo byChesapeake Bay Program) and Chicago City Hall (Wikimedia Commons); page 14:Air Force Space Command, Colorado (photo by Thea Skinner) Sentry Roof Services, LLC, all copyrights reserved14
2018w w w.sen t r yr oof .com4535 S. Berkeley Lake Rd. NW,Norcross, GA 30071(678) 301-5555
Metal roofing systems can be warranted from five to 30 years and cover materials including panels, underlayment, and even paint finish. SENTRY ROOF SERVICES ROOFING SYSTEMS Metal roofs are also better for the environment because most are made from recycled materials, which means fewer new materials were sourced to create metal commercial roofs.
