Pramod V. Patil, Product Manager [Waterproofing Systems], BASF Construction Chemicals (India) Pvt. Ltd. Mumbai

Preface

Waterproofing of Roof be it concrete, metal decks, timber, etc. has always been a challenge job to the construction industry. With the increased complexity of structures and the complex nature of utilization of this roofs, terraces or podiums and with possibility of structural movements and growing concern on leakages in the structures has created a need for a simple reliable roof waterproofing system.

This article provides an insight to single ply synthetic waterproofing membranes and high performance liquid applied waterproofing membranes for roof which have global reputation and have gain quick acceptance in recent times in India.

Roof Waterproofing Demands

  • A system which can allow to take the movements in structure
  • A system that can allow itself to carry heavy intense built-ups such as - landscaping or gardens or ballast / pavers etc.
  • A system robust enough to take pedestrian / vehicular traffic
  • A system that can be used to refurbish roofs without disturbing or breaking off the existing substrate
  • A system that can be left exposed to atmosphere
  • A UV stable system
  • A system with reliability and aesthetics.
  • A system that demands to be laid loose or unbonded to the substrate
  • Long-life expectancy and maintenance free or minimal maintenance
  • A complete water-tightness

Prevailing Roof Waterproofing Practices & Viewpoint

Rigid waterproofing barriers A conventional practice of rigid waterproofing such as brick-bat koba and crystalline waterproofing has limitation if structure is designed to undergo movementsduring life span.

Flexible & elastomeric waterproofing membranes This type of waterproofing forms a membranous barrier against water leakage. They are as follows:

They come in form of liquids, either single component or multi-component, applied with hand or spray. They could be cementitious polymer modified or acrylic or P.U. based or bituminous or epoxy based.

They come in form of preformed membranes, either made up of modified bituminous membranes (APP, SBS), PVC, TPO, HDPE, EPDMs etc. they are either torch applied, stuck with adhesive, mechanically fixed.

Rigid waterproofing barriers have shown limitation or failure when subjected to certain aggressive conditions or structural movements during its life span. Bituminous / cementitious polymer modified / EPDM membranes / HDPE based systems do enable elongations but have limiting success, application difficulties and deteriorate with time in limited life span of application.

The reasons of failure of systems are many, it could be wrong system application or the behaviour & limitations of the material itself in terms of adhesion or UV stability etc. Over a period of time excellent development for different types of waterproofing materials and system have been taking place, keeping in mind the criteria or requirements for a good engineered & reliable Roof Waterproofing System.

This article provides insight to the success stories in India & some glimpse of international reference, where a well engineered and reliable Roof Waterproofing Systems has been implemented in various situational demands:

TPO Membranes System: a single ply waterproofing membranes

Coniroof Waterproofing System: Spray or hand applied cold liquid PU roof waterproofing system

Single Ply Synthetic Waterproofing Membranes

Single-ply synthetic waterproofing membranes are widely used in Europe and North America for the past 40 years and have proven performances. The concept is to provide a watertight liner all around the susceptible building element and to ensure the right technique to install the membrane. There are various synthetic liners available for the purpose and the selection is based on the expected performance out of them in the specific situations. The single-ply synthetic liners are designed and build to the various situational needs and normally consisting of synthetic roll of fixed thickness and width and are available in reinforced with glass or polyester fibres options. Today, PVC and TPO are the most popular choice of materials for the application in the civil industry. The synthetic liners have life expectancy of 25 to 50 years v/s 10 to 15 years as offered by bituminous membranes, a single factor which made synthetic liner the popular choice in the construction sector over the years. PVC membranes are manufactured by adding plasticiser in the PVC and this limits their life expectancy in the case of direct exposure to UV and required to be protected, as plasticizers may migrate out of the membrane making the membrane brittle. Thus, PVC membranes have become chosen material for underground and buried situations while TPO, which expensive in comparison to PVC has excellent stability in UV and available in range of colors, has become the choice for exposed roofing situations, ideally suitable for Tropical conditions as in india.

MASTERPREN TPO Liners

MASTERPREN TPO is a new generation synthetic liner made using an innovative formulation: EPR (ethylene propylene rubber) modified polyolefin. MASTERPREN TPO development has been based on experience, synergy, co-operation and manufacturing technologies:

Experience gained by Flag who, since 1963, have developed and manufactured synthetic waterproofing liners for use in the roofing, civil engineering, and hydraulic sectors.

Synergy with industry-leading manufacturers of polyolefins, who have developed and introduced these new materials to the field of waterproofing.

Co-operation with the most qualified designers, general contractors, and installation companies.

Innovative manufacturing technologies for synthetic waterproofing materials.

Main Characteristics of MASTERPREN TPO Liners

The exclusive manufacturing system designed for this type of liner and its unique formulation have resulted in:
  • Excellent weldability
  • Softness and flexibility
  • Excellent dimensional stability
  • High weather and UV rays resistance.
  • Non-toxicity
  • Resistance to a wide range of chemical attacks
  • Compatibility with most insulation panels, including expanded/extruded polystyrene
  • Compatibility with oxidised bitumen
  • High resistance to puncturing
  • Resistance to roots and micro-organisms
  • Adaptability to structural movements
  • Environment and user–friendly
  • Life expectancy in excess of 25 years
  • Proven installation history
MASTERPREN TPO waterproofing membranes can be used for both newly built roof systems and for renovating existing roofs. MASTERPREN TPO membranes have been designed both for ballasted roof systems (protected) and for exposed roof systems (unprotected).

MASTERPREN TPO for more effective light reflecting surface, is manufactured from modified polyolefin with an in ice white finish as standard (with any RAL color available to order) providing very high resistance to weathering and ultraviolet rays. In the research phase, the color of the side exposed to the aggressive action of atmospheric agents was improved so not only did the lighter color reduce the heat within the roof build up, but it produced a more efficient light reflecting surface.

The inherent anti-oxidising and UV-absorber properties of MASTERPREN TPO enabled Flag’s research team to improve the membrane’s resistance of the thermo-plastic polymer to light and atmospheric agents by as much as 30% in the development of TPO.

Environmental Impact

MASTERPREN TPO Plus membranes have a positive environmental impact which starts during production and ends with a recyclable product with a 25 year life expectancy. MASTERPREN TPO Plus membranes do not contain harmful chlorines, bromide or halogens.

The development has not been limited to the mere theoretical assessment. Technical tests have been carried out relating to the re-use and recovery wastes from the production process and from end of life products.

The TPO Plus has an FAA fire rating from Warrington Fire Research Centre.

TPO Plus is manufactured to UNI EN ISO 9001 and UNI EN ISO 14001 certified plant standards

Extensive tests were performed in the Xenotest and the QVU Weathering Tester.

Typical Applications

MASTERPREN TPO membranes can be applied in the following circumstances:
  • Exposed roofing laid loose
  • Exposed roofing mechanically fixed
  • Exposed roofing fully bonded (requiring a fleece backing)
  • Landscaped areas
  • Roof gardens
  • Old Roofs for Refurbishment, without disturbing the existing substrate.
  • May be used in underground structures and water storage structures etc.

Manufacturing Process for MASTERPREN TPO Membranes

MASTERPREN TGE, MASTERPREN TPE liners are manufactured in UNI EN ISO 9001 certified plants and fully comply with the performance standards CEN European Standard, UNI 8629/6 – SIA 280 – DIN 16726. The raw material used to produce MASTERPREN TPO membranes is created by blending a mix of synthetic polyolefins and softening agents (EPR) with various additives that, through a catalloy procedure, are transformed into a moulded mass and then into granules. This combines:
  • Resistance to ageing, weathering and micro-biological attack
  • The EPR compound gives softness and flexibility with a high resistance to mechanical and chemical influences in conjunction with the strong welding capacity of polypropylene
The unique manufacturing process designed and developed by Flag combines a tri-extrusion process in a single pass encapsulating a reinforcement mesh that produces a complete homogeneous product with stability and high tensile strength and an effective dual light/dark colour signal layer. The particular property of MASTERPREN TPO synthetic liners is the reinforcement insert embedded in the body of the liner. This reinforcement may be a non-woven glass mesh or polyester mesh, according to application needs, ensuring an efficient and aesthetically flawless end result. MASTERPREN TPO liners are produced by co-extrusion in two-colours, known as a “signal layer” system. The upper sand-grey colour, which provides lower heat absorption, increased longevity and aesthetic qualities, represents 10-15% of the membrane thickness and the black underside, which protects against UV damage, 85-90%. The major benefit of the system becomes apparent during installation; should the membrane become damaged, the black underside is immediately detected by the contractor and simply repaired.

Situation– Roof Waterproofing Over Precast Segment

Application Case Study- MASTERPREN TPO Membrane at Bangalore International Airport

Project: Bangalore International Airport

Client: BIAL, Bangalore

Scope of Project: Roof waterproofing of terminal building

Design & Construction: Larsen & Toubro Limited, ECC Construction group

Year of execution: 2006 to 2008, Completed

Systems used: MASTERPREN TPE

Project Description

The roof of terminal building is made up of large precast segment, each of having 24 metre span and 10m length. Total there are more then 200 segments in the terminal building. The curve shape and complex detailing made client to choose most reliable waterproofing membrane which can be quickly installed and can last for the design period of the structure.

The Solution offered

Considering the complexity of the job and life expectancy, 1.2mm thick MASTERPREN TPE was selected. MASTERPREN TPE is polyester reinforced TPO membrane, manufactured by latest tri-extrusion process. Considering the wind loading on the structure the fasteners are designed. On the diaphragm walls the membrane is fully adhered to the substrate using special MASTERPREN adhesive glue.

Situation:– Refurbishment & Waterproofing of Old Roof Without Disturbing the Existing Substrate

Application Case Study- MASTERPREN TPO Membrane at IIT- Mumbai Convocation Hall

Project: IIT Mumbai, Convocational Hall Roof

CIient: IIT- Indian Institute of Technology, Mumbai.

Scope of Project: Roof Refurbishment with Waterproofing of old RCC Folded roof of convocation hall.

Year Completed: 2008

System Used: MASTERPREN TPE

Project Description

The convocation hall at IIT-Mumbai is about 35years old structure. The Roof of this hall is RCC roof about three inches thick RCC folded panels. Over the period of time various waterproofing systems have been tried to make the roof waterproof. The system used were from conventional IPS to brush applied polymer coating to Bituminous felts. The water-tightness of the roof could not be achieved to it satisfaction and with time and exposure to the elements has failed to give water-tightness to the roof, resulting in leakages and seepage of water into the RCC roof slab. This seepage of water has added to the corrosion into the slab and the concrete is spalling and has become week. IIT was thus looking for a system that could assure water-tightness to the roof and also one does not have to disturb the existing surface of the slab, to prevent damage to the structure.

Solution Offered

Considering the complexity of the job with earlier done various layers of existing on substrate cannot be removed and life expectancy, 1.2mm thick MASTERPREN TPE was selected. MASTERPREN TPE is polyester reinforced TPO membrane, manufactured by latest tri-extrusion process. Considering the situation of doing the treatment over the prevailing surface the MASTERPREN TPE was loosely laid over the roof with mechanical fixing at the end terminations using fasteners with certain customized detailing.

Liquid Cold Applied PU Coating Membrane System Coniroof Waterproofing System

CONIROOF is based upon the use of epoxy resin/polyurethane preparation coatings. Combined with polyurethane based waterproofing membrane and surface coating.

CONIROOF has been designed to provide a minimum of 25 year performance expectancy in severe climate conditions as a fully bonded waterproofing solutions for:
  • Built-up roofing systems
  • Overlay systems
  • Podium decks
  • Inverted roofing
  • Can be applied on Concrete, Timber, Clay tiles, Metal Decks, Precast etc
CONIROOF membrane can be sprayed or hand applied onto different types of substrate by using polyurethane or epoxy resin preparation coats and primers.

Features

Fast Installation: New spray technology applies up to 700 m² / day of the waterproofing membrane including detailing

Monolithic: No laps welds or seams, the inherent weakness of sheeted systems – makes for reliable detailing

Fast-setting: 30 seconds after application

Cold applied: Requiring no hot works and presents no fire risk

Fire retardant: Meets DIN 4102: Part 7, BS 476: Part 3

Lightweight: Less dead load on existing structures / substrates

Solvent-free: No-odour

Robust: Designed to take vehicular traffic without damage

Ideal for Landscaping works: Roof garden and decking

Seamless Detailing: No laps, welds or seams to seal providing simple effective waterproofing of difficult detailing situations

Elastomeric: Will stretch and contract with the movement of the roof

Application:

  • SPRAY APPLIED: Fast track seamless solution for complex or larger areas
  • HAND APPLIED: Perfect for Confined and Restricted spaces

  • Certification: BBA (British Board of Agreements) Approved membrane systems for flat or pitched roofs that are exposed to UV or light traffic (pedestrian and maintenance). Suitable for mixed roof situations where sections are exposed and there are roof gardens or landscaping.

    Coniroof Built-up

    CONIROOF is a Seamless, monolithic robust waterproofing system obtained from several application stages:
    • Cleaning and Surface Preparation.
    • Selection and application of preparation coats/primers.
    • Sand board-casting on the primer to have mechanical keys for anchoring.
    • Spray or Hand Application of the waterproofing Membrane, as per requirement.
    • Application of Top Coat for Exposed surface: The final stage of Coniroof system is the use of a single component, moisture curing, UV resistant protective coating.
    Situation– Roof Waterproofing of Roof with Clay Tiles of A Heritage Structure

    Application Case Study- coniroof spray applied waterproof system on pitched roof with Clay tiles

    Project Name: St Mary’s Church Hongkong, Pitched roof waterproofing

    CIient: St Mary’s Church, Hongkong

    Scope of Project: Waterproofing of Pitched roof with Clay tiles and to retain the heritage look.

    System Used: Coniroof 2111–Roof deck crack-bridging P.U. Waterproofing system (spray applied membrane)

    Project Description

    A heritage structure with pitched roof covered with clay tiles and in colored pattern. Clients want to retain the same look and do not want to remove the tiles to avoid any damage to the heritage structure.

    System Solution

    Considering the requirement Coniroof spray applied system was suggested. Coniroof waterproofing system offered a reliable roof waterproofing and helped in maintaining the heritage look of the structure.

    Situation– Complex Roof Waterproofing of Mosque in Kuala Lumpur Malaysia

    Application Case Study- coniroof spray applied waterproof system on the complex details on the roof.

    Project Name: Mosque Kaula Lumpur, Malaysia

    Scope of Project: The Roof Waterproofing of Mosque

    System Used: Coniroof 2111–Roof deck crack-bridging P.U. Waterproofing system (spray applied membrane)

    Project Description

    The concrete roof of the mosque is of complex nature with small domes and ventilators spread across the roof. This small domes are covered with tile bits. The entire roof is to be waterproofed without disturbing the substrate.

    System Solution

    Considering the requirement Coniroof spray applied system was suggested. Which gave a good waterproofing system and helped in covering the most complex details on the roof and making it watertight..

    Conclusion

    Finally local availability of single-ply synthetic waterproofing membrane and Coniroof system, an engineered watertight system shall enable building owners and structural designers to have choice of dependable waterproofing material. The experienced application team and easy access to global experts shall enable BASF to serve the construction industry better.

    NBMCW April 2009