Foundations of Real Estate Management BOMA International Module 4: Building Operations II Roofing Systems

Objectives List the components of a roofing system Describe the difference between built-up roofs, modified bitumen roofs, and single-ply roofs

Roofing Systems Out of sight… out of mind

Roofing Systems Long-term fixed asset Use life cycle cost analysis to determine best roof system for your application Goal: Longest roof system life with lowest life cycle cost

Why Do Roofing Systems Fail? End of the roof’s useful life Inadequate maintenance Poor or improper design Poor or substandard installation Faulty materials

Roofing Components Decking (deck) Insulation Roofing materials Concrete or corrugated steel panels Insulation Roofing materials

Roofing Systems Flat roofs Pitched roofs Drains and gutters Not really “flat” – there is some degree of pitch Usually pitches to front or back of property Sometimes pitches to the center Pitched roofs Drains and gutters

Roofing Systems Inspect roofs for ponding Keep the insulation dry Increases chance of leaks Adds significant amount of weight Keep the insulation dry

Common Roofing Systems Built-up roofs Most expensive installation cost Modified bitumen roofs Moderately expensive installation cost Single-ply membrane roofs Least expensive installation cost All roof systems should have walk paths to prevent damage

Built-Up Roofs Alternating layers Usually 3-4 layers Roofing ply sheets (felt) Asphalt or coal tar pitch Usually 3-4 layers Final layer is either topped with gravel or is smooth (top sheet)

Built-Up Roofs

Modified 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 bitumen Usually 2 layers – base sheet/top sheet Fire hazard – fire watch for 60 minutes after work has concluded

Modified Bitumen Roofs Applied with hot asphalt, a propane torch, or cold asphaltic adhesive

Modified Bitumen Roofs

Single-Ply Membrane Roofs Made up of a single ply of roofing material Three main types: EPDM (ethylene propylene diene monomer) Rubber PVC (polyvinyl chloride) Vinyl TPO (thermoplastic olefin) Plastic

Single-Ply Membrane Roofs Adhered to the roof: Ballasted (stones) Mechanically attached (fasteners) Fully adhered (adhesives)

Single-Ply Membrane Roofs

Single-Ply Membrane Ballasted roof system

Mechanically attached roof system Single-Ply Membrane Mechanically attached roof system

Fully attached roof system Single-Ply Membrane Fully attached roof system

Single-Ply Membrane Seams Can be manufactured in white EPDM Seams are sealed and need routine maintenance PVC and TPO Seams are heat welded together Can be manufactured in white Does not reduce cooling costs Upper floor HVAC system is insulated Does reduce heat island effect in urban environments

EPDM Seam Management

Roof Maintenance Best Practices Semiannual roof inspections Equipment installations on roof and roof penetrations should always be supervised by roofer holding warranty Remove leaves, plant material, and trash on regular basis Inspect drains and ensure drains work properly

Grass growing on the roof Roof Maintenance Grass growing on the roof This is not a green roof!

Roof drain clogged with debris Roof Maintenance Roof drain clogged with debris

Roof Maintenance Remove debris. Better yet – don’t let it accumulate in the first place!

Roof Warranty Usually 10 to 25 years Understand warranty requirements Roof inspections and preventive maintenance are usually required Keep copies of all documentation! Make sure you use vendors certified and approved by manufacturer

Green Roofs Partially or totally covered with vegetation Advantages Amenities space Reduce heating and cooling costs Reduce “heat island effect” Increase lifespan of the roof Reduce storm water runoff Filter pollutants and CO

Green Roofs