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Norwalk CT 203 858 0080 / Pittsburgh PA 203 858 0080 / Longview TX 903 -291-0848
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TPO Roofing: Advantages and Disadvantages for Commercial Flat Roofs

TPO roof - The seams are normally the isuues

TPO Roofing for Commercial Roofs 

A Thermoplastic Polyolefin, or a TPO roofing system, installed on commercial flat roofs, consists of a laminated vinyl membrane which comes in 2 thickness options; .045 and .060 thousandths of an inch, which is only equivalent to the thickness of a quarter.

TPO roofing - affected by extreme colds

TPO Roofing Advantages:

  • The seams are welded, rather than glued, so they are less prone to separation if properly heated.
  • Contractors are certified by the manufacturer to install the membrane and the manufacturer honors the warranty.   
  • TPO’s white surface reflects much of the ultraviolet light, keeping the structure below cooler.

TPO Roofing Disadvantages:

  • The system is fairly new to the roofing industry; only about 15 years, with a long track record of revisions and improvements due to surface and seam failures.
  • Repairs are part of maintenance due to shrinkage from prolonged exposure to harmful UV rays causing stress on seams and flashing.
  • Contractors must calibrate welding machine correctly, otherwise, seams may come loose during the first freeze/thaw cycle and lead to water infiltration.
  • The manufacturer’s warranty is only 15-20 years.
  • When both the walk-behind and hand-held welding is done, a special tool is need to check the welds. If the welding did not take, it will require patching.
  • *Different welders must be used on long seams and short seams.

*It has been our experience that TPO seams are not welded uniformly, which causes the seams to fail and the roof to leak. The walk-behind welder, that is used to weld lengthy seams, cannot weld the short seams around skylights, vents, drains, and a/c units. A hand held heat gun must be used in these tight areas, and the transition from where the larger heat welder left off to where the heat gun is used, becomes an issue because the applied heat differs. A good read is GAF’s study on TPO.

TPO Roofing Membrane

TPO is a single ply vinyl membrane, as thick as a single quarter, and comes in wide rolls of between 8 and 16 feet. A glue down process adheres the membrane to a substrate. The seams are welded with a walk-behind welder and a hand-held heat-gun. When seams are heat-welded, it is of the utmost importance that the heat be perfectly calibrated throughout the day of installation, otherwise, cold, wind, and humid weather conditions, will affect the quality of the welded seams. When TPO roofing has been installed, a tool must be used to check the quality of the seams to ensure that the heat-weld has taken.

TPO- The thickness of a coin

TPO Roofing – Surface Preparation

Before a TPO roofing system can be installed, the substrate must be free of dust, dirt, and debris to provide a smooth surface for the gluing process, however, installing a recovery board over an existing roof, can also provide a smooth surface. Regardless of the type of surface preparation, the TPO roofing system is still a single ply membrane that will not last as long as a two ply Modified Bitumen Torch Down Rubber Roof Membrane System.

TPO can not be installed over any surface

Summary

Although TPO is a good roofing system, there are still many inconsistencies with the heat-welded seams. Seam separation is prominent in cold weather climates. Also, the thin laminated membrane is very susceptible to punctures due to foot traffic, which is not covered by the manufacturer’s warranty. A good read is GAF’s study on TPO.

TPO can easily be pierced by objects when stepped on
3D Video demonstrating the best drain and strainer system
Skylight flashing explained and corrected
Metal roof Repair - easy and permanently

We Provide the Following Services to:

Residential and Commercial Flat Roof

Tel. Numbers

Connecticut – 203 246 -6089

Pennsylvania – 724 221 2968

Drain Strainers for a flat roof. Custom strainers are better. Watch this video how it works
Improving-drainage-for-a-flat-roof by lowering the drain Watch video
Installing a Retrofit Drain on a flat roof - Watch Video
Best draining system for a flat roof - See this video about a drain that was lowerde 15 years ago
Cracked skylight seal causing leaks - watch this 3d animated video to see where a skylight can leak
Installing a flat roof over Tar and Gravel roof. This is a two ply roofing system that is the best in the industry -Watch the video
 UltraViolet beating a EPDM rubber roof - watch this video to see how a EPDM rubber got destroyed
EPDM Rubber Seam Problems - the most common place for EPDM rubber roofs to leak is at the seams - Watch Video
Deciding when to replace or repair a flat roof - Watch this video to help you make decisions
Ultraviolets will damage EPDM Rubber roofs prematurely - Watch the video to see how bad ultraviolets are for a rubber EPDM roof
Metal Roof Rusting Through - Almost any metal roof can be recovered or repaired - Watch this video

Tel Numbers:

Connecticut –  203 858 0080 

Pennsylvania –  724 221 2968

EPDM Rubber destroyed by ultraviolet rays
3D Video explaining where leaks happens on post on flat roofs
Plexiglass skylight - a stupid mistake cause so much trouble
Caulking incorrectly applied causes leaks behind flashing
Small Drain Issues - Very common problem on flat roofs
Drains for flat roofs - Installing a Retrofit drain demonstration

 TPO Roofing- by Roofing Contractor

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Five Commercial Flat Roof Systems Explained – Watch Video

This Video Explains about the Three roofing systems – TPO. EPDM and Modified Bitumen Torch Down

Five Commonly Used Flat Roof Systems 

There are 5 types of commercial flat roofing systems commonly installed:

  • Built- Up Roof (BUR) also known as the “Hot-Tar-and-Gravel” Roof System
  • Metal Panel Roof System
  • *2 Ply Modified Bitumen Torch Down Rubber Roof System
  • Single-ply membranes such as TPO, PVC and EPDM Systems
  • Spray polyurethane foam-based Roof System.

*Commercial Roof USA specializes in the installation of 2 Ply Modified Bitumen Torch Down Rubber Roof System.

This is a BUR system also known as a Tar and Gravel roof.

Built-Up Roof Systems (BUR)

The BUR system has been in use in the U.S. for over a 100 years. It is commonly referred to as a “Hot-Tar-and-Gravel” Roof System. These roofs are composed of layers of saturated asphalt paper and moped down hot liquid coal tar or asphalt. Saturated paper is layered in a criss-cross pattern, and depending on the contractor, as many as 12 layers of paper and coal tar or asphalt can be used during the installation.

Coal tar or asphalt is heated in a kettle with propane gas and pumped up to the roof top. Hot tar is spread over the work surface with a mop or squeegee, and the felt paper is rolled out over it.

Asphalt is a petroleum product refined from crude oil and coal tar comes from the distillation of coal. Either way, the coal tar or asphalt is the adhesive, that when combined with many layers of felt paper, forms a thick membrane that becomes the roof.

After the membrane has been built-up, a thin layer of coal tar or asphalt is mopped over the entire roof and aggregate stone of 1/2” is spread over the entire membrane. This stone is used to protect the roof from harmful UV rays.

The “Build Up” has “Come Down”

The BUR roofing system can last many decades, but beyond that, there will be a certain amount of degradation. Petroleum based products will become dry and brittle and start to crack, due to evaporation, causing leaks.

The BUR roofing system is expensive to install, due to the labor and materials involved. These roofs have been known to last for over 50 years, because of the multiple layer “build up.”  Some of them have had as many as 15 -20 layers of paper and tar, however, we have also seen that some contractors would “come down” with the number of layers, to as many as 5 and to as few as 3.

Metal Panel Roof Systems

The Structural Metal Panel Roof System is a type of metal roof system used for a low slope application. It is common to see metal panel roofs over warehouses and factories. The metal panels can span up to 4 ft., from rafter to rafter and can support the weight of a person. A special sealant is used between seams and overlapping joints to prevent water from entering. Neoprene washers are used where bolts fasten the metal roof to the metal rafters. These metal panels are excellent water barriers and will prevent water from leaking through when correctly installed. This type of roof can last for 40 to 50 years, when properly maintained.

Metal roofs systems can be repaired.

Modified Bitumen Membranes

The Modified Bitumen Torch Down Rubber Roof System (MB) was developed by the Italians in the 1960s and made its way to the U.S. by the late 1970s. The rubber membrane is made of reinforced fabrics covered with asphalt, which consists of modifiers that give the asphalt its elastic properties on both sides. The modified asphalt is manufactured in widths of 36″. Because of the rubberized technology, these membranes are referred to as rubber roofs or rubber membranes.

There are 2 Types of MB Rubber Roof Membranes:

APP – is a Modified Bitumen membrane that is fully torched down to the fiber base, and the torch is also used on the seams, hence the name – Torch Down Membrane.

SBS – is a Modified Bitumen membrane that uses cold or hot mopping tar or asphalt adhesives. Some SBS membranes are self adhering; the backing is very sticky, and will adhere to the surface it is rolled onto.

The MB membranes have 3 types of surfaces: smooth surface, mineral surface, and a foil laminate surface. The minerals of the surface have been coated with a ceramic material that protect the rubber against harmful UV rays.

The MB roof system is typically installed as a single-ply system, however, we specialize in a 2-ply system to extend the roof life to 40 years or more. We have come to specialize in this roofing system for many reasons, but the most important one, is in terms of maintenance, because the Modified 2 Ply Bitumen Torch Down Rubber Roof System, needs minimal to none.

Single-Ply Membranes: EPM, TPO, and PVC

EPDM, TPO, and PVC are single ply synthetic membranes, and are manufactured in wide sheets. These membranes are very thin and come in rolls from 8 – 20 feet widths.

Adhesives are used to adhere these membranes to the properly cleaned substrate. If the substrate is not properly prepared; removal of dust and particles, according to manufacturer’s instructions, the adherence is compromised, and the life of the roof is reduced.

EPDM is made from 2 compounds that are derived from oil and natural gas and the seams are glued together with a liquid adhesive that has been reformulated 4 different times. Currently, as a remedy, a new self-adhering cover tape is placed over the seams. These membranes are not well protected from harmful UV rays and are prone to degradation.

The Image below is a Modified Bitumen Torch Down Rubber Membrane with Embedded Ceramic Granules for UV Protection

The image is an example of a 2 Ply Modified Bitumen Torch Down Rubber Roof System.

The Image Below is a White TPO Vinyl Roof with Little UV Protection.

A White TPO Vinyl Roof with Little UV Protection.
3D Video demonstrating the best drain and strainer system
Skylight flashing explained and corrected
Metal roof Repair - easy and permanently

Different flat roof systems explained

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TPO and PVC Roofing – Single Ply Commercial Roofing Systems

TPO – A Single Ply Vinyl Roofing Membrane

Thermoplastic Polyolefin or TPO, is a single ply vinyl roofing membrane that is manufactured in rolls of 8-16 feet wide, and is typically white in color. To install a TPO commercial roofing system, the roofing contractor must be certified by the manufacturer. The flashing used around skylights, vents, a/c units, drains, and drip edges is pre-manufactured specific to each commercial roof. Seams are bonded on site with the use of hot-air, walk-behind welding machines that must be calibrated throughout the day, because of temperature changes.

TPO Roofing - A Single Ply Commercial Roofing Systems

TPO Origins and Performance History

In 1991 Flexible Polyolefin (FPO) membranes were first introduced in Europe. United States manufacturers introduced and produced TPO membranes and helped gain a steady market share in the roofing industry because of its economical price. The average membrane consists of a 0.064 inches (1.6 mm [63 mils]) in thickness. The most common TPO thickness used in the U.S. is 45 mils. and many of the products labeled “45 mils.” actually have as little as 32 mils. of the polymer3 formulation. European manufacturers use fiberglass and polyester to reinforce the membrane, but a U.S. produced TPO reinforced membrane will expand and contract 5 to 7 times more.TPO cannot withstand the temperature swings that occur in much of North America. TPO membranes also need the proper cleaning solvents that must be used in the installation process to achieve consistent seaming. The properties and chemical formulations that lead to the membrane’s deterioration and failures are due to the choosing of the membrane’s thickness, and the reinforcement used. Nevertheless, TPO manufacturers in the US are looking forward to creating an improved formulation that would have the advantages, of another single ply membrane, known as Polyvinyl chloride, or PVC, without risking its marketable price tag.

PVC Origins and Performance History

Polyvinyl chloride (PVC) has been in the U.S. roofing market since 1970 and continues to hold its reputation in relation to durability and quality performance. It has a flame retardant property with an exceptional chemical resistance and lower stress cracking issues. However, history reveals that PVC underwent the same downfalls that TPO did during its early stages in the U.S. roofing industry. This led to the questioning of U.S. manufacturer’s reliability in comparison to its European counterpart.

Evidence showed that TPO and PVC demonstrated top performance in Europe, but failed in US during its entry into the market due to its inability to withstand the temperature swings that occur in much of North America. Hence, the conclusion was made that U.S. manufacturers prioritized profit over quality. The exact specifications were sacrificed resulting in the production of poor quality versions of both membranes.

In view of this fact, the National Roofing Contractor’s Association’s (NRCA’s) research showed that U.S. versions of PVC membranes were thinner than what were produced and installed by its European counterparts. The huge difference was clear as dimensions showed 30-40 mils vs. 60 mils. Furthermore, the formulation and installation were far from the truth because such things were not done in Europe.

U.S. manufacturers began to look for exact adjustments to the membrane’s formulation. Finally, PVC earns a reputation as a top performing single-ply roofing product in the U.S. roofing industry.

Conclusion

Because TPO and PVC membranes are single-ply roofing systems, they will only provide a 15 year-performance, at best, with numerous maintenance needs. Maintenance repairs, prior to the adjustments, will come from the installation of a thinner membrane, installation workmanship, and maintenance crews that inadvertently puncture the thin membrane, by stepping on nails or screws lying around while working on rooftop units. Therefore, PVC is a costly investment to make for a roof that will not last beyond 15 years.

Installing a flat roof over Tar and Gravel roof. This is a two ply roofing system that is the best in the industry -Watch the video
 UltraViolet beating a EPDM rubber roof - watch this video to see how a EPDM rubber got destroyed
EPDM Rubber Seam Problems - the most common place for EPDM rubber roofs to leak is at the seams - Watch Video
Deciding when to replace or repair a flat roof - Watch this video to help you make decisions
Ultraviolets will damage EPDM Rubber roofs prematurely - Watch the video to see how bad ultraviolets are for a rubber EPDM roof
Metal Roof Rusting Through - Almost any metal roof can be recovered or repaired - Watch this video

Tel Numbers:

Connecticut –  203 858 0080 

Pennsylvania –  724 221 2968

EPDM Rubber destroyed by ultraviolet rays

 The repair and Installation of TPO Roofing We benefit on Google if you write a comment on TPO Roofing systems.

Use “flat roof”  or “TPO Roofing” as keywords in your comment. Thanks a lot.