7Roofing Systems Flat roofs Pitched roofs Drains and gutters Not really “flat” – there is some degree of pitchUsually pitches to front or back of propertySometimes pitches to the centerPitched roofsDrains and gutters
8Roofing Systems Inspect roofs for ponding Keep the insulation dry Increases chance of leaksAdds significant amount of weightKeep the insulation dry
9Common Roofing Systems Built-up roofsMost expensive installation costModified bitumen roofsModerately expensive installation costSingle-ply membrane roofsLeast expensive installation costAll roof systems should have walk paths to prevent damage
10Built-Up Roofs Alternating layers Usually 3-4 layers Roofing ply sheets (felt)Asphalt or coal tar pitchUsually 3-4 layersFinal layer is either topped with gravel or is smooth (top sheet)
12Modified Bitumen Roofs Residual material after crude oil is refined (“the bottom of the barrel”)Instead of ply sheets, system uses thermoplastic or elastomeric coating materials and bitumenUsually 2 layers – base sheet/top sheetFire hazard – fire watch for 60 minutes after work has concluded
13Modified Bitumen Roofs Applied with hot asphalt, a propane torch, or cold asphaltic adhesive
19Mechanically attached roof system Single-Ply MembraneMechanically attached roof system
20Fully attached roof system Single-Ply MembraneFully attached roof system
21Single-Ply Membrane Seams Can be manufactured in white EPDM Seams are sealed and need routine maintenancePVC and TPOSeams are heat welded togetherCan be manufactured in whiteDoes not reduce cooling costsUpper floor HVAC system is insulatedDoes reduce heat island effect in urban environments
23Roof Maintenance Best Practices Semiannual roof inspectionsEquipment installations on roof and roof penetrations should always be supervised by roofer holding warrantyRemove leaves, plant material, and trash on regular basisInspect drains and ensure drains work properly
24Grass growing on the roof Roof MaintenanceGrass growing on the roofThis is not a green roof!
25Roof drain clogged with debris Roof MaintenanceRoof drain clogged with debris
26Roof MaintenanceRemove debris. Better yet – don’t let it accumulate in the first place!
27Roof Warranty Usually 10 to 25 years Understand warranty requirements Roof inspections and preventive maintenance are usually requiredKeep copies of all documentation!Make sure you use vendors certified and approved by manufacturer
28Green Roofs Partially or totally covered with vegetation Advantages Amenities spaceReduce heating and cooling costsReduce “heat island effect”Increase lifespan of the roofReduce storm water runoffFilter pollutants and CO