Roofing EPDM membranes

Details of EPDM membrane and its applications in roofing is presented in Section 3.5. 

EPDM Membrane Application in the Construction Industry for Roofing and Waterproofing... 

Bonding EPDM membrane with a cold adhesive is appropriate when structures are too light or roofs are steep with curves or sharp corners. Before application of the adhesive, the surface should be made smooth, clean, free from dust, oil, grease or other contaminates which may affect the adherence. This method is economical to cover all types of complex structures even on vertical walls. The sheets can be adhered to smooth surfaces of cement concrete, wood and metallic surfaces made of steel, aluminium, etc. An adhesive bonding system is also suitable for use on rigid insulation and old concrete roofing. 

For example, more and more manufacturers, contractors, consultants, and building owners are turning to these techniques to solve in-service roofing membrane problems as well as to evaluate new roofing membrane materials. A typical example is the paper on the problem of EPDM membrane shrinkage The study was conducted in 1995 to investigate the causes of... 

EPDM is by far the most widely used material in the ballasted roofing system constmction. Because of EPDM s flexibiHty, very large sheets of up to 10,000 square feet (929 m ) can be deHvered to the job site in compact roUs that offer reduced labor on the roof in the seaming process. The typical EPDM sheet size used in ballasted systems is 12 by 30 m and 1.1 mm thick. EPDM is also widely used in both the fully adhered and mechanically fastened roofing systems. In these constmctions, both 1.1- and 1.5-mm thick material is used with widths from 2.1 to 15 m. A majority of the installations use nonreinforced sheet, although reinforced membrane can also be used in all of the system types. The majority of the reinforced sheets go into mechanically fastened systems. 

More than 800 million pounds of EPM and EPDM polymers were produced in the United States in 2001. Their volume ranks these materials fourth behind styrene-1,3-butadiene copolymers, poly( 1,4-butadiene), and butyl rubber as synthetic rubbers. EPM and EPDM polymers have good chemical resistance, especially toward ozone. They are very cost-effective products since physical properties are retained when blended with large amounts of fillers and oil. Applications include automobile radiator hose, weather stripping, and roofing membrane. 

During the last decade many new roofing materials were introduced which are applied in the form of weldable membranes, liquid curable materials, self-adhesive products, and torchable materials. These materials are produced from numerous polymers such as, PVC, chlorinated polyethylene, chlorosulfonated polyethylene, EPDM, acrylics, bitumen, polymer-reinforced bitumen and several other materials. It is beyond the scope of this book to analyze compositional changes in these materials. We will provide a brief overview. 

Polysar H DM. iiles/Pdysar Rubber] EPDM polymers for iig. mdding, hose and ptc e extrusion, sponge and cast coring, roofing membranes, black sidewalls. 

Polysar EPDM. [Miles/Pedysar Rubber] EPDM pedymns fro inj. medding, hose and prriBle extrusion, qxxige a cast curing, roofing membranes, black sidewalls. 

Although the material most used for single-ply membranes is EPDM, in competition with it are several other materials— Du Pont s Hypalon (a chlorosulfonated polyethylene), its Neoprene products, and modified PVC. It is believed that future growth in the roofing market will depend on products, such as Hypalon, that are easy to handle and have good ozone resistance, and on PVCs modified with polymeric plasticizers. 

Also, attempts were made to add a certain amount of a fresh carbon black into the devulcanized rubber. It was shown that the vulcanizates containing a fresh carbon black exhibited better properties than the revulcanized rubber without an addition of fresh carbon black. However, in some cases, even carbon-filled devulcanized rubber shows mechanical properties similar to or better than the original rubber. In particular, this was shown for EPDM roofing membrane containing carbon black and significant amount of oil (Yun and Isayev, 2003b). Apparently, oil plays an important role in devulcanization process. Possibly, the presence of oil prevents a deactivation of the filler that was observed in vulcanizates not containing oil. But in order to prove this hypothesis further experiments are required. 

A low molecular weight PIB is used in many adhesive compositions. It plays role of a plasticizer and/or a tackifier. Adhesive composition based on EPDM rubber, useful in water-tight joints of roofing membranes, contains 5-9 wt% A pressure sensitive... 

Uses of Ethylene-Propylene Rubbers. EPDM and EPR vulcanizates are used in extruded profiles, cable insulation and jacketing, and roofing membranes. There are many automotive uses radiator hose, door and trunk seals, insulation, jacketing, and others. These elastomers are also used in applications such as window and architectural profiles, dock fenders, and washing-machine hoses. In short, their applications are extensive and diverse. Ethylene-propylene rubbers may be the most versatile of general-purpose rubbers. In addition, EP rubbers are added to polyolefin plastics as impact modifiers and as components of certain thermoplastic elastomer compositions (e.g., thermoplastic vulcanizates, which are discussed later in this chapter). 

Thermoset membranes are compounded from rubber polymers. The most commonly used polymer is ethylene, propylene and a small amount of diene that is vulcanized with various accelerants. This polymer, referred to in the industry as EPDM, is commonly known as rubber roofing . Another thermoset rubber roofing material is neoprene, although this particular formulation is rapidly being replaced by EPDM. Finally, the rubber/plastic hybrid Hypalon is also considered as thermoset. Hypalon is unique in that it is manufactured as a thermoplastic but, because it cures over time, becomes thermoset. 

The insulation system for pitched roofs usually provides the advantage of a continuous, homogeneous insulating layer with an economy in construction. Bitumen (asphalt) as well as its different versions modified with various polymers and a number of different roofing membranes, i.e., preformed or liquid applied sheets of PVC, terpolymer of ethylene-propylene-diene monomer (EPDM), chlorosulfonated polyethylene (Hypalon), PU, butyl rubber, polychloroprene (Neoprene) [36], all have been used as insulating layers. 

PVC and PE have played a major role in the shift of early roof waterproofing technology and materials. After the introduction of elastomeric and other thermoplastic materials, flexible membranes of polychloroprene (Neoprene) rubber, butyl rubber and Hypalon were used. Later on, liquid PU, solvent-based liquid acrylate and liquid EPDM systems, in addition to new materials like SBS modified bitumens, were also used in the management of roofing. All fall into the single-ply family of roofing, which offers a much cleaner, safer, energy-efficient and cost-effective alternative to built-up roofs. 

To meet these desirable properties, the appropriate polymer to consider would be ethylene - propylene-diene terpolymer (EPDM). In the manufacture of a cost effective, impermeable membrane system, EPDM rubber is the right choice as a discreet material for improved waterproofing and protective lining applications in roofing and other uses in the construction sectors [125]. 

EPDM rubber-based membrane can meet the stringent requirements to prevent water seepage on roof tops, vertical walls, ground and basement walls in construction applications. 

EPDM roof sheet is one of the lightest roof membrane materials because of its low specific gravity. It is highly suitable for lightweight structures and puts negligible extra load on the roof to be waterproofed. It is serviceable over a wide range of temperatures -50 °C to 150 °C, and the membrane does not embrittle in freezing condition nor soften in hot weather. 

In many countries asphalt felt coating is used to protect the building roof from leaking -the life of such a waterproofing system is only two to three years. For exceptional water and weather resistance the EPDM roof membrane is known to be serviceable for more than 20 years and virtually no maintenance is required. 

Ballasting is an economical and quick system to secure an EPDM roof membrane. Waterproofing sheet is simply fitted over the flat roof or to a low slope, and covered with cleanly washed well rounded gravel with a diameter of 40-50 mm. Corners may be ballasted with suitable concrete slabs to prevent the sheeting from wind uplift and the perimeter can be fixed with contact adhesive. 

---