The construction industry in Europe has been in decline since 2008, with figures from Euroconstruct showing total spend of €1444 billion in 2008, €1316 in 2009 and an anticipated €1264 in 2010. Jon Nash of AMI Consulting reviewed this data in a market paper at the annual AMI conference Waterproof Membranes 2010, which took place in December in Cologne, Germany. Around 50% of construction was new build this year. The situation is expected to improve in 2011 with around 1% growth. Civil engineering has been sustained throughout this time frame by government expenditure. The Russian market has been studied by NTC Gidrol-Krovlja using data from sources such as Rosstat: the country's GDP dropped by 7.9% in 2009, but started to rise again in 2010 by an anticipated 2.1%. The construction market fell by 16% in 2009, and a further 1% in 2010, which led to a 20% fall in output of waterproofing materials in 2009 and one third of companies left the market. In 2009, 1.2% of membranes were imported and single ply membranes comprised 75% of the quota, with Finland supplying bituminous, and Germany and Switzerland polymer products.
In the Middle East, Polaris International (a division of the Khalifa A. Algosaibi Group of Saudi Arabia) has established a new PVC and TPO waterproof membrane production plant in the Kingdom of Bahrain with 2 coextrusion lines. The company conducted market research in Saudi Arabia, which showed that bitumen still holds the main market share at 25%, with PVC at 21% and other polymer membranes (EPDM, TPO, etc.) at 21%, alongside liquid polyurethane systems at 21%. The Arab Water Seal company has been providing waterproofing since 1998 in the United Arab Emirates and estimates that around 40% of the Middle East uses bitumen waterproofing, 26% is liquid applied, 20% is PVC, and 5% each is EPDM and HDPE, with the remaining 4% going to bentonite. The trend in the region is towards green building products and construction including LEED accreditation for new projects (Leadership in Energy and Environmental Design). The Princess Noura bint Abdurrahman University in Saudi Arabia is the largest new development with 38 buildings and at least 3 of these are aiming for gold LEED status. Solar panels are being combined with waterproofing membranes using technology from companies such as Solar Integrated, which uses components from its parent company, Energy Conversion Devices (ECD). United Solar makes thin film laminates for this market and has annual production of 150MW: over 6 million square metres has been installed worldwide. Integration into the membrane avoids adding the weight and wind load of conventional crystalline photovoltaic systems and an ETFE front cover protects the system. TDDK in Dresden is using this system to generate average energy output on some of its factory roofs of 677MWh/year.
Trelleborg Waterproofing has examined the environmental aspects of membranes, including the use in walls for waterproofing and airtightness (typically EPDM or PVC membranes), which conserves energy. The driver in Europe is the Energy Performance of Buildings Directive 2010/31/EU, which requires that all new buildings must be nearly zero energy by 2020. In the UK air tightness is now a specified test (Part L Building Regulations 2010). The company supplies products such as EPDM roofing panels, which can be electrobonded using the Centrix system from Afast BV. In this system, metal stress plates in the roofing support structure are activated by a magnetic induction system to heat them, which activates their surface coating and bonds the support to the membrane. The membrane panels are joined using hot bond vulcanisation or TPO thermofusion techniques.
Production equipment for membranes is a big investment. A typical reinforced geomembrane comprises one or more synthetic sheets coated or laminated to a fabric reinforcement. The interadhesive layer can be extruded on the top and underside of the fabric. Typically the amount of plastic used in coating is 200 to 500 gsm according to Davis-Standard, the machinery suppliers. A combination of two co-located extruders can extrude adhesive and bulk polymer simultaneously and the edge trim can be added back in to reduce waste and cut material use. Krauss-Maffei Berstorff has looked at the different requirements for extruders, depending on the form in which the material is supplied to the membrane manufacturer. For example, a single screw extruder is sufficient for processing precompounded TPO and PVC pellets at a rate of up to 500 kg/h, while a co-rotating twin screw extruder is needed for high output (over 1500 kg/h)and direct compounding.
TPO-based membranes are now widely used, for example in the Tempodrome in Berlin (Sika). LyondellBasell have compared it to other materials: less is needed, which can reduce transport and other logistical costs. It has good root resistance for green roofs and can be produced in light colours to reflect sunlight and cut building cooling costs. To reduce dust and dirt on the roof, a thin polypropylene film can be added by heat lamination - this was tested on a roof in Ferrara, Italy in 2009.
In 1987, a 2-component spray on membrane based on polyurea was introduced in the USA and this market is growing globally at 10%/year, mainly in the US and Asia as Europe is only now developing an interest in this technology. BASF supplies this polymeric material in the form of an isocyanate and an amine. The reaction of the 2 components is very fast, reaching green strength in seconds. It is used in landscaping with geotextiles, in containment, in truck beds and roofing and as a simple way to repair flat roofs.
Another innovation in the US that is now being offered in Europe is the polyurethane foam adhesive system from ADCO Roofing Products. It can be used to attach fleece-backed EPDM, TPO, PVC, and SBS-modified bitumen membranes. A similar 2-part polyurethane system has been in use for attaching insulation since the 1970s. According to the SPRI, 52% of membranes are now attached using adhesives, 43% by mechanical methods and 5% use ballast.
Fluoropolymers are at the top of the range of roofing membranes and are used in transparent domes and other structures: this is an area where Hightex has expertise. In a project at Green Point Stadium in Cape Town in 2009, 27,000 square metres of PTFE-coated silver glass fabric was used, while in Johannesburg 50,000 square metres of the same structure (sand-coloured) was used in the Soccer City Stadium. Hightex currently has projects in the Olympic Stadium in the Ukraine, BC Place in Vancouver and the National Stadium in Warsaw. At the company office a pneumatic ETFE membrane incorporates flexible photovoltaic panels. If the Gottlieb -Daimler Stadium in Stuttgart incorporated photovoltaics over 80% of the area, it could generate 730,000kWh/a.
Dow Elastomers has studied formulation for membranes: an aluminium trihydrate flame retardant is halogen-free and allows high production rates. The polyolefins can have high stabilizer additions to reduce the effects of weathering, without causing plate out or affecting welding.
Cynthia Teniers of EVAL Europe has been studying the use of ethylene-vinyl alcohol copolymers (EVOH) to reduce volatile organic compound (VOC) loss through geosynthetics. Liners are used to protect the environment by containing liquids and vapour emissions; however current monolayer membranes can permit VOCs to pass through. If a 2-4% EVOH layer is added to a PE or PP membrane, or even to the clay liner, it can greatly improve the barrier performance. During production of the multilayer polymer membrane an adhesive tie layer is needed.
H&R ChemPharm has developed a new liquid applied super absorbent polymer system, which forms a film coating and embeds in the substrate. It is currently in use in cables in a coated-yarn layer to protect optical fibres. The company has received enquiries from consultant geo-engineers about using this system in geomembrane applications as it blocks water and contaminants and is self-healing. The Technical University of Munich and Bolton Textile Institute have been studying the potential. The production method is simple - fabric is immersed in a bath of polymer and then pressed through heated rollers above 120C before being rolled up.
Fire performance is a critical requirement of building materials. Warrington Fire Gent carries out fire testing to look at factors like flame spread. The standards which apply to roofing include ENV 1187 (CEN TS 1187) and EN 13501-5. Protocols include placing a basket of wood wool onto the roof construction test sample and flaming for 30 minutes with the roof at different angles. Each European member state chooses a test method and level of safety.
The International Green Roof Association has highlighted the safety features for roofing including wind uplift, structural load bearing capability, fire regulations and drainage. It is particularly important to check the membrane joins and to test for leaks. A finished roof needs fall protection, which can be a rope and harness system for maintenance, or full fencing for a roof with public access. High rise gardens have been opened in Singapore and New York offering a park experience in the centre of the city.
In the late 1950s Fatra produced one of the world's first PVC geomembranes for use in a dam in Dobsina. This Czech company now produces waterproof membranes for a variety of applications including ground waterproofing for new buildings, which need to act as a radon and moisture barrier. The advantage of synthetic membranes is the speed of installation, low labour, movement with the building minimising tears and cracks, and excellent chemical resistance. However, they are thin compared to bitumen and can be torn during installation. An active check system can be built in to show where leaks are occurring and to facilitate repair. It is much more critical to get ground waterproofing right first time, because of the difficulties of access and the consequences of failure. Leak detection systems are available from Sensor in Bratislava and permit remote monitoring of membrane installations.
The waterproof membrane market is growing worldwide and providing multifunctional components to the construction industry and aiding in the move to LEED certification, by incorporating cooling, gardens and alternative energy functions. The next AMI networking event for the industry, Waterproof Membranes 2011, is scheduled in November 2011 at Cologne, Germany.