Introduction To Single-PlyIntroduction To Single-Ply

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ObjectivesObjectives

When you complete this unit, you will be able When you complete this unit, you will be able to:to:

Explain what single-ply roofing is.Explain what single-ply roofing is. Describe the advantages and disadvantages Describe the advantages and disadvantages

of single-ply roofing.of single-ply roofing. Look up the features of a single-ply material.Look up the features of a single-ply material. Discuss the three factors that ensure your Discuss the three factors that ensure your

safety.safety.

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Single-Ply RoofingSingle-Ply RoofingSingle-Ply roofing is any roofing system that Single-Ply roofing is any roofing system that

uses only one layer of roofing material instead uses only one layer of roofing material instead of built-up layers. of built-up layers.

All single-ply systems must provide three basic All single-ply systems must provide three basic qualities: qualities:

WaterproofingWaterproofing StrengthStrength Surface protectionSurface protection

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WaterproofingWaterproofing is provided by the roof membrane. is provided by the roof membrane.

StrengthStrength is usually provided by a reinforcement is usually provided by a reinforcement scrim (a mat of fiberglass, polyester, etc.) scrim (a mat of fiberglass, polyester, etc.) embedded in the membrane. embedded in the membrane.

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ScrimScrimMakes the membrane:Makes the membrane:• StrongerStronger•Resists puncturesResists punctures•Keeps it from crackingKeeps it from cracking•Helps the membrane expand and contractHelps the membrane expand and contract•Improve appearance of the roofImprove appearance of the roof•Hold down the membrane and insulationHold down the membrane and insulation•May be fire resistantMay be fire resistant•May reflect heatMay reflect heat

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MEMBRANEMEMBRANEThe membrane is a sheet of single-ply roofing.The membrane is a sheet of single-ply roofing.

Different materials are used for the membrane. Different materials are used for the membrane. Membranes should have these features:Membranes should have these features:

Good appearanceGood appearance High tensile strength High tensile strength FlexibilityFlexibility Long lifeLong life Easy maintenanceEasy maintenance Installing single-plyInstalling single-ply

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Single-Ply MembranesSingle-Ply Membranes Membranes must be able to:Membranes must be able to: Adjust to building movement.Adjust to building movement. Expand and contract with temperature changes.Expand and contract with temperature changes. Hold up under aging and temperature extremes.Hold up under aging and temperature extremes. Resist weathering.Resist weathering. Resist the effects of ozone and ultraviolet rays. Resist the effects of ozone and ultraviolet rays.

(Ozone is a form of oxygen that can be damaging. (Ozone is a form of oxygen that can be damaging. Ultraviolet (UV) rays from the sun shorten the life of Ultraviolet (UV) rays from the sun shorten the life of the membrane.)the membrane.)

Resist becoming brittle at very low outdoor Resist becoming brittle at very low outdoor temperatures.temperatures.

Resist tearing.Resist tearing.

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Defective MembraneDefective Membrane

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Membrane ThicknessMembrane ThicknessMembrane thickness may range from about 40 Membrane thickness may range from about 40

mils to 120 mils. mils to 120 mils. The most common sizes are 45, 60, and 90 The most common sizes are 45, 60, and 90

mils. mils. A mil is 0.001" (one thousandth of an inch). A mil is 0.001" (one thousandth of an inch). Because membranes are relatively thin, mils Because membranes are relatively thin, mils

are easier to use than fractions of an inch. are easier to use than fractions of an inch.

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Membrane ThicknessMembrane ThicknessThe comparison below will give you an idea of The comparison below will give you an idea of

mil thicknesses:mil thicknesses: 45 mils—Slightly over 1/32" (about as thick 45 mils—Slightly over 1/32" (about as thick

as a dime) as a dime)

60 mils—1/16" (about as thick as a nickel)60 mils—1/16" (about as thick as a nickel)

120 mils—Almost 1/8"120 mils—Almost 1/8"

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Membrane SizeMembrane SizeMembranes are usually applied in sizes as Membranes are usually applied in sizes as

large as is practical to handle.large as is practical to handle.

This reduces the number of seams (which cuts This reduces the number of seams (which cuts down labor costs) and reduces the chance of down labor costs) and reduces the chance of leaks. leaks.

Common sizes are 6 to 50 feet wide and 100 Common sizes are 6 to 50 feet wide and 100 feet long. Some membranes are up to 250 feet long. Some membranes are up to 250 feet long.feet long.

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ADVANTAGESADVANTAGESSingle-ply roofing has many advantages:Single-ply roofing has many advantages: May be lighter than built-up roofing. May May be lighter than built-up roofing. May

sometimes be laid over the existing roof, sometimes be laid over the existing roof, avoiding the cost of removing the old roof.avoiding the cost of removing the old roof.

Easier to work with: Less material to haul up Easier to work with: Less material to haul up to the roof. No hot bitumen and kettle to to the roof. No hot bitumen and kettle to handle. Fewer seams to seal.handle. Fewer seams to seal.

Expands and contracts more easily. Flexible Expands and contracts more easily. Flexible with temperature changes and movements of with temperature changes and movements of the building.the building.

Attractive: Comes in different colors. Attractive: Comes in different colors. Adapts to any shape of roof.Adapts to any shape of roof.

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DISDISADVANTAGESADVANTAGES

Single-ply roofing has these Single-ply roofing has these disdisadvantages:advantages: Products and installation methods change Products and installation methods change

often because manufacturers are constantly often because manufacturers are constantly improving the products and methods.improving the products and methods.

Some products are not yet time-tested.Some products are not yet time-tested. Some membranes are damaged by grease, oil, Some membranes are damaged by grease, oil,

asphalt, tar, etc. asphalt, tar, etc.

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DISDISADVANTAGESADVANTAGES

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Single-ply systems must be installed Single-ply systems must be installed exactly to specs.exactly to specs.

The designer and the roofer must know what The designer and the roofer must know what materials will damage a product.materials will damage a product.

Damage to a new roof by other crafts is a Damage to a new roof by other crafts is a constant problem. constant problem.

Some systems have to be installed at a Some systems have to be installed at a certain temperature range.certain temperature range.

Shrinkage can cause damage at base Shrinkage can cause damage at base flashings.flashings.

Some membranes and materials have a short Some membranes and materials have a short shelf life. shelf life. (cont.)(cont.)

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Single-ply systems must be Single-ply systems must be installed exactly to specs.installed exactly to specs.

Many solvents and adhesives are a fire Many solvents and adhesives are a fire hazard or health hazard. hazard or health hazard.

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Single-plySingle-ply

Leaks are difficult to find, especially on Leaks are difficult to find, especially on ballasted systems.ballasted systems.

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Single-ply systems must be Single-ply systems must be installed exactly to specs.installed exactly to specs.

The system is unforgiving. The seams The system is unforgiving. The seams are the only barrier against moisture, so are the only barrier against moisture, so they have to be done right the first time.they have to be done right the first time.

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Wind & Air Pressure DangersWind & Air Pressure DangersWind uplift has to be considered for any Wind uplift has to be considered for any

single-ply roof. single-ply roof. Manufacturers have ratings for how much air Manufacturers have ratings for how much air

pressure a roof system can withstand. pressure a roof system can withstand. Designers have wind speed maps that Designers have wind speed maps that

give the fastest wind speed for an area. Roof give the fastest wind speed for an area. Roof designs are based partly on this.designs are based partly on this.

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Wind Map SpeedWind Map Speed

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Wind & Air Pressure Wind & Air Pressure DangersDangers

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Wind & Air Pressure Wind & Air Pressure DangersDangers Other wind conditions have to be Other wind conditions have to be

considered.considered. The taller the building, the more the speed and The taller the building, the more the speed and

direction of the wind on the roof can vary. direction of the wind on the roof can vary. The building location (for example, among tall The building location (for example, among tall

buildings or surrounded by hills) affects wind buildings or surrounded by hills) affects wind patterns. patterns.

The building structure, for example, the corners The building structure, for example, the corners of a roof have a high wind uplift because a of a roof have a high wind uplift because a partial vacuum is created at the edge, partial vacuum is created at the edge, especially if there is a parapet wall. The higher especially if there is a parapet wall. The higher the parapet wall, the stronger the negative the parapet wall, the stronger the negative pressure.pressure.

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Wind & Air PressureWind & Air Pressure

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Wind & Air Pressure Wind & Air Pressure DangersDangers

Air pressure from below can also be a problem. Air pressure from below can also be a problem. For example:For example:

A building has large overhead doorsA building has large overhead doors The doors are openedThe doors are opened Air pressure rushes into the buildingAir pressure rushes into the building This put pressure on the underside of the roof This put pressure on the underside of the roof

membranemembrane Enough air pressure raises the membrane Enough air pressure raises the membrane

causing damage and leakscausing damage and leaks

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NRCA photos of roof damage from Hurricane Charley.

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MATERIALSMATERIALSThere are three categories of single-ply roofing There are three categories of single-ply roofing

materials:materials: ThermoplasticsThermoplastics Modified BitumensModified Bitumens ElastomersElastomers

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ELASTOMERSELASTOMERSElastomersElastomers have elastic, rubber-like qualities. have elastic, rubber-like qualities.

There are two types—cured and uncured:There are two types—cured and uncured: Cured elastomers cannot be formed. They Cured elastomers cannot be formed. They

are generally used for the field membrane.are generally used for the field membrane. Uncured elastomers can be formed. They Uncured elastomers can be formed. They

are generally used for detailing.are generally used for detailing.

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ThermoplasticsThermoplastics

A thermoplastic becomes soft when heated A thermoplastic becomes soft when heated and can be hot-air welded. and can be hot-air welded.

It can be reshaped as needed for detailing. It can be reshaped as needed for detailing. Hot-air welding fuses membranes together.Hot-air welding fuses membranes together.

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Modified BitumensModified Bitumens

Modified bitumen's are asphalt sheets Modified bitumen's are asphalt sheets modified with plastics or rubber.modified with plastics or rubber.

Chemically, they are quite different from Chemically, they are quite different from elastomers or thermoplastics. However they elastomers or thermoplastics. However they are generally classed with single-ply are generally classed with single-ply membranes.membranes.

Modified bitumen's are generally applied by Modified bitumen's are generally applied by torch, hot asphalt or modified adhesives. torch, hot asphalt or modified adhesives.

Some are self-adhered (Peel & Stick).Some are self-adhered (Peel & Stick).

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SurfacingsSurfacings

Surfacing may be applied in the factory or in the Surfacing may be applied in the factory or in the field. Factory-applied surfacings may be such field. Factory-applied surfacings may be such things as:things as:

Liquid coatingLiquid coating Embedded granulated mineralsEmbedded granulated minerals Laminated metal foilLaminated metal foil

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Surfacings Surfacings Ballast (rock or pavers)Ballast (rock or pavers) Mineral granules Mineral granules Liquid coatingLiquid coating

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Learning About ProductsLearning About Products

By visiting a manufacturers website you can By visiting a manufacturers website you can access information like:access information like:

Systems: TPO, EPDM, BUR, PVC, Systems: TPO, EPDM, BUR, PVC, MODIFIESMODIFIES

Details and DrawingsDetails and Drawings SpecificationsSpecifications Safety Data SheetsSafety Data Sheets Videos and moreVideos and more

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Safety and HealthSafety and HealthThe most important subject in your training is safe The most important subject in your training is safe

working practices. working practices.

If an accident leaves you handicapped or dead, If an accident leaves you handicapped or dead, all your skill as a roofer means nothing. all your skill as a roofer means nothing.

And it can happen to YOU in one second.And it can happen to YOU in one second.

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Safety and HealthSafety and Health

Roofing is one of the most dangerous trades. Roofing is one of the most dangerous trades. It is always among the ten industries with the It is always among the ten industries with the

highest accident rates. highest accident rates. The odds are against you unless you work to The odds are against you unless you work to

change them for yourself. change them for yourself.

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Safety and HealthSafety and Health

Look at four other roofers on the job. Look at four other roofers on the job.

Statistics say that you or one of these four will be Statistics say that you or one of these four will be injured on the job this year. injured on the job this year.

That is 1 in 5—very bad odds—and only you can That is 1 in 5—very bad odds—and only you can change them.change them.

We think of roofing in terms of falls and blunt We think of roofing in terms of falls and blunt physical trauma but hazards come in various physical trauma but hazards come in various forms.forms.

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HazardsHazards FallsFalls Sprains and StrainsSprains and Strains BurnsBurns ElectrocutionElectrocution Hit By ObjectsHit By Objects Fires and ExplosionsFires and Explosions NoiseNoise Hazardous SubstanceHazardous Substance Heat and ColdHeat and Cold UV DangerUV DangerWe will study roofing and waterproofing hazards We will study roofing and waterproofing hazards

extensively through out your apprenticeship.extensively through out your apprenticeship.

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Hazardous MaterialsHazardous Materials

There are two important things to understand There are two important things to understand about hazardous materials: about hazardous materials:

The hazards vary considerably with different The hazards vary considerably with different products.products.

Hazards can be short term (acute) or long Hazards can be short term (acute) or long term (chronic). You may not notice any term (chronic). You may not notice any effects when you are working with a effects when you are working with a material, but you could be disabled from it 5, material, but you could be disabled from it 5, 10, or 20 years later.10, or 20 years later.

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Safety Data SheetsSafety Data Sheets

Review SDS to see what safety precautions are Review SDS to see what safety precautions are needed.needed.

What type of PPE do I need.What type of PPE do I need. What if I get some on my skin or in my eyes?What if I get some on my skin or in my eyes? Is it flammable?Is it flammable? How do I extinguish a product if it’s on fire?How do I extinguish a product if it’s on fire? How should I store it?How should I store it?

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End of Chapter 1End of Chapter 1 Thank You Thank You