By admin

Avoid the Landfill by Recycling Vinyl Roofing

Tags :
Categories : Articles

The time has come to establish a post-consumer, vinyl-roof recycling program in the U.S.

 

Carl De Leon, Vinyl Roofing Div., CFFA

 

Skyrocketing raw-material costs, higher landfill tipping fees, legislation to restrict disposal of construction materials-and an architectural community that demands the lightest environmental footprint that can be achieved-all are leading toward the mainstreaming of post-consumer recycling. In the not-too-distant future, specifiers will call for post-consumer content in a roof project. With its European counterparts blazing the trail, the North American vinyl (PVC) roofing industry has entered a new phase in its commitment to environmental sustainability through recycling.

Because thermoplastic single-ply vinyl membrane can be heated and reformed repeatedly over its lifespan, it has long been an industry best practice to recover production trimmings and scrap and recycle the material into new membrane. Well-run, properly equipped vinyl-membrane production plants are capable of converting virtually all of the raw material and components that go into making the membrane into the final installed roof system (or other applications).

The re-roofing of Boston’s Marriott Long Wharf hotel was a pilot project with an ideal recycling scenario. The project was close to the membrane manufacturer’s head office, and a local recycler had an established program for handling thermal insulation.

Typical post-industrial recycled products have included accessories such as roofing walkway pads, commercial-grade flooring, and concrete expansion joints. In addition, scrap can be reintroduced as a raw material into a subsequent membrane-manufacturing process. Some roofing manufacturers collect their customers’ scrap, as well as the general-purpose scrap of other vinyl fabricators, for reuse in production of new membranes.

Building on this track record, the member manufacturers of the Vinyl Roofing Div. of the Chemical Fabrics & Film Association (CFFA), Cleveland, have initiated a feasibility study to evaluate strategies for making post-consumer recycling workable on a broad scale, as it has been in Europe for many years.

Where it began
Vinyl roofs have been in use for more than 40 years in Europe, and roofing manufacturers there have been recycling retired roofs into other useful products since 1994. That was the year a consortium of companies funded the construction and operation of a facility in Germany to reclaim the growing volume of vinyl membranes at the end of their service lives, and return them to the original manufacturers.

Over the years, the material taken back has been used in a variety of applications, including as feedstock in the production of new roofing membranes. Typically incorporated into the back side of the sheet where potential color variations are not a factor, the recovered material can comprise 5% to 15% by weight of the finished product. Reports from the field indicate that, at 10+ years of age, the first membranes made with recycled post-consumer material are performing the same as membranes produced of virgin raw materials.

Today, RoofCollect, a European Single Ply Waterproofing Association (ESWA) program, (www.eswa.be), coordinates the recovery and processing of post-consumer vinyl roofing membranes. In conjunction with the European Commission, ESWA sets annual targets for post-consumer roof recycling. In 2006, 4.4 million lb. of roofing membrane were recycled due to the efforts of the association.

ESWA is now working with the recycler Interseroh (Cologne, Germany) to establish a pan-European collection system that would facilitate recycling in closer proximity to the job site. ESWA is also investigating strategies for incorporating higher percentages of recycled material into finished membranes.

Less is more
According to the U.S. Environmental Protection Agency, Washington, construction and demolition waste total an estimated 136 million tons annually. The vinyl roofing industry is committed to combining existing post-consumer recycling technologies with logistical expertise to limit its contribution to these numbers.

Post-consumer recycling of vinyl roof membranes in the U.S. began in 1999. Working in tandem with a vinyl membrane manufacturer, a Massachusetts recycling company produced a highway cold-patching material made from old vinyl roofing membranes and other recovered plastics. Today, state-of-the-art grinding equipment makes it possible to process roofing membrane and convert it into feedstock for new materials.

Only membranes that have been mechanically attached or loose laid have been reprocessed in North America. There is no experience as yet with membranes that have been adhered to insulation or to other substrates, but CFFA members are watching some approaches that have been developed in Europe.

Pilot projects shed light
Post-consumer recycling of roof membranes has occurred on a limited basis in the U.S. To date, the savings in disposal fees and the value of the salvaged materials have generally exceeded the cost of the additional labor, shipping, and grinding fees. However, the total net costs are dependent on total roofing square footage, the distance that the old roof material must be shipped to be processed, and avoided landfill tipping fees.

The re-roofing of Boston’s Marriott Long Wharf hotel was a pilot project where the recycling scenario reflected the ideal logistics:

  • All involved parties were motivated to recycle as much of the complete assembly as practical.
  • The project was close to the membrane manufacturer’s head office.
  • A local recycler had an established program for handling thermal insulation, resulting in minimal incremental freight charges as a percentage of overall salvage costs, in addition to the necessary experience handling and processing the old roofing membrane.

Other system components recycled included the gravel ballast, the metal flashings, and the extruded polystyrene insulation. In the end, 95% of the existing materials of the assembly, by weight, was recycled. The membrane was returned to the manufacturer for use in other membrane products. The contractor estimated a savings of 25%, compared with traditional disposal costs, even with the additional handling required.

A more typical scenario occurred with the Univ. of Iowa’s (Iowa City, IA) Carver-Hawkeye Arena. The project’s building team was committed to incorporating a recycling strategy into its roof-replacement project. However, there was no local insulation recycling program to help defray the shipping costs, and the manufacturer was much further away from the job site.

Nonetheless, university officials found this approach a cost-effective choice compared with tipping fees at a landfill, besides being more environmentally friendly. The aged roof was rolled up and was first sent to a Cedar Rapids, IA, recycler to reduce the material volume through grinding. This minimized the volume of material to be shipped back to the membrane manufacturer, as well as the associated freight charges.

Later, the membrane manufacturer processed the material into roofing walkway membrane, an installation safety product normally made of virgin post-industrial vinyl. Scheduling of this project allowed for some of the walkway material produced from the recycled roof membrane to be used on the new roof.

What are the challenges?
Many end-users and plastic recyclers recognize that plastics used in durable goods are often more valuable than those found in packaging. But mainstreaming recovery of these plastics is complicated by a number of unique challenges. Among them:

  • a much wider range of different and incompatible plastics
  • a less developed collection infrastructure
  • more varied end-products
  • lower overall volumes of these materials, particularly on an individual grade basis
  • a much wider range of attached foreign materials, such as metal, rubber, foams, and fabrics.

A sustainable recycling strategy requires high-quality reclamation, reprocessing efficiency, and a ready customer base for the recycled product. With this in mind, the CFFA feasibility study on post-consumer vinyl roof recycling is looking at ways to address the following issues on a large scale.

Reclamation
Any long-term approach to reclaiming old roofs will need to address the training of roofing contractors in the logistics of tearing down the roof system for recycling, instead of preparing it for landfill disposal. Slightly more handling is involved, as the contractor must separate the membrane from other waste materials and prepare it for shipping. Issues include:

Preparing and storing the membrane for transport to the recycler: Old membranes must be cut into strips of prescribed widths and lengths, and tightly rolled and tack welded before leaving the job site for the recycler.

As part of the planning process, roofing contractors will need to preorder gaylord boxes and pallets from the membrane manufacturer, in a quantity based on the surface area of the roof, the membrane thickness, and the existing assembly construction. Scrap membrane and trimmings from the new installation can be added to the gaylord boxes for recycling as well.

Delivering a clean product to the company providing size-reduction and grinding services: For best results, the processor needs to receive a membrane free of foreign materials such as stone ballast and metal fasteners.

Issue: Processing
Many processors can grind reclaimed materials, but special equipment is needed to reduce vinyl roofs to chunks or a powder. This equipment separates such components as felt backing material and the reinforcing polyester matrix. Issues include finding a recycler that can process reinforced material.

Until recently, felt-backed membranes could not be reprocessed and had to be landfilled. Newer equipment can separate the felt, allowing the sheet to be recycled with ease. This equipment can also extract the encapsulated scrim reinforcement from the polymer matrix. The felt backing and scrim can be used as fibrous filler when fabricating concrete blocks for landscaping.

Issue: Identifying the market
The success of roof recycling, as is the case with all recycling, depends on the will of the participants in the process. Issues include developing a customer base and collection infrastructure.

The North American vinyl roofing manufacturers are committed to developing the infrastructure to establish a viable program. Given a strong desire for sustainable construction in the marketplace and efforts to divert construction waste from landfills, it appears that the time is right for roof recycling to grow.

For more than 40 years, durable, highly engineered, light-colored vinyl roofing membranes have cooled and protected buildings in climates around the world. They feature a long life cycle, coupled with the associated lower energy consumption to produce the raw material and process it into useful products. This is a significant determinant of their sustainability as a building product, but it doesn’t stop there. The vinyl roofing industry is committed to taking it to the next level and establishing a North American post-consumer recycling program.