Preformed (PWM) and Liquid Applied (LAM) Waterproofing Membrane Systems
Raja Haria
Ensuring Waterproofing Done Right FIRST Time – Expert in Preventive & Remedial Solutions | Structural Waterproofing Consultant | Construction & Engineering Entrepreneur
What is Liquid Applied Waterproofing Membrane (LAM)?
Liquid Applied Waterproofing is a process of waterproofing application using special liquid. It's used for roofs like flat roofs, pitched roofs, domed roofs and walls also.
Liquid applied Membrane involves Fully bonded monolithic coating application. This coating once cures forms a rubber like elastomeric waterproofed membrane.
LAM are flexible enough to take any shape they are laid to, also they have properties like strength, tear resistance, weathering resistance, UV stability & elasticity to bridge the cracks developed underneath the surface.
These kind of membrane has excellent elasticity and they regains the original shape without any damage to the membrane when removed from tension.
LAM can be reinforced with secondary level materials like fibre glass or glass reinforced plastic to add more tensile strength to the membrane. Once these secondary materials are added the LAM losses the regain-ability.
LAM when applied, encapsulates the surface they are installed to and thereby preserves its underneath from weathering.
LAM are easy in application and are high performance waterproofing material along with economically viable waterproofing solutions for exposed and covered roofs.
Liquid applied Waterproofing membranes are mainly applied on above-ground envelopes. These are not advisable for the below-grade structures.
These systems are air cured quick drying, so any Waterproofing contractor in India would try to finish entire surface area in a single day or in a continuous shift to avoid formation of cold joints. However in extreme giant area of waterproofing work these cold joints are overlapped by few feets and rest in taken care as normal.
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What is Pre-Formed Waterproofing Membrane (PWM)?
Pre-Formed waterproofing is also called Sheet based waterproofing. In this type of waterproofing, a layer of water tight material is laid over surface and bonded to surface with varieties of options like Torch, Adhesive or Primer etc. PWM membrane composes of multiple thin layers of such waterproofed materials and bonded together to form pre-formed waterproofing membrane. Ideally these membranes comes in thickness of 2mm to 4mm?in a roll form and?in verities of width ranging from 2' (two feets) to 10' (ten feets) depending on application purpose. They are overlapped to each other by minimum of 2" (two inches) to 4" (four inches) and are bonded with each other?by help of hot polymer based adhesives.
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Pre-formed membrane comes in different types:
The main caution zone of these membrane based waterproofing treatment is joint processing & bonding to the mother surface.
These systems are stiff, relatively less elastic than LAM, but they are highly durable due to their thickness.
These systems are usually proposed in below-grade waterproofing systems. Yet now-a-days they are also been applied to open to sky and covered roofs.
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Liquid applied continuous membrane?based waterproofing?vs?Pre-formed membrane based waterproofing
It is always an often question we get hit by many of our clients, who asks what are better option between a Liquid is applied membrane & pre-formed membrane?
Just thought to share a quick comparison chart between Liquid applied seamless membrane-based waterproofing using polyurethane, acrylic based vs pre-formed membrane-based waterproofing using EPDM, PVC, Bitumen?membranes.
Hope the above brief helps you get the better idea in a schematic format and helps selecting better system as per your project / site requirements.
Article could be viewed on?www.waterproofingraja.com. |?Article Link
Innovating Leak Prevention & Building Protection | Mentoring Structural Waterproofing Leaders | Founder & Chairperson at Raja & Raja?
6 年Add the categorical brief of the products next time! Keep it up!
Vice President at WICR Waterproofing & Decking
6 年Fluid applied all the way. Add fabric to it for reinforcement, and you have an invincible membrane. My only critique is that fluid applied membranes are in fact used frequently in a multitude of below grade applications. For example, a backfilled CMU or concrete wall can receive any roll or spray on application from Tremco, Epro, UPI, Pacific Polymers. EPRO manufacturers a spray on lagging application for lagging walls with submerged conditions, and/or methane.? Otherwise, your notes about the systems are accurate, but can be very system specific.?
Regional Sales Director at Axter Ltd
6 年The fact you suggest liquid waterproofing application is semi skilled says quite a lot about the bias contained within the article, and one of the major issues that our industry faces at present. You've also stated that "sheet membranes" are not fully bonded, which again, is not true. There are multitudes of fully bonded bitumiouns systems on the market from many different suppliers and manufacturers. Axter Ltd, the company I've worked for for nearly ten years, manufacture, supply and design all types of waterproofing systems for the market, including hot melt, reinforced bituminous membranes, PVC single ply and a variety of liquid applied systems. This allows us to select the right product for the intended use of the roof. There is no silver bullet to waterproofing, and to suggest there is, is the route cause of many leaking roofs within the UK.
Vice President (Self-employed)
6 年Dear Mr.?Raja Haria RR, How it can be positioned better against liquid PU membranes? The Kalmatron? KF-B mortar binds cracks by penetrating into deteriorated concrete & changing its theology. It is not a crystalline filler material, but instead becomes part of the structure: https://www.kalmatron.com/3-KF-B.html The compressive strength of KF-B is 25 MPa. For example, if two concrete prisms are glued together with the Kalmatron? KF-B mortar, they cannot be broken apart at the seam. Membranes should not be used with KF-B at all. KF-B waterproofs from both the negative and positive sides. Tricalciumalumochloride formed as a result of reaction (3) forms hardly soluble solid phases when water is released for simultaneous hydration reactions. The alkali and the internal pore moisture form solutions inhibiting metal corrosion that also have a low eutectic temperature of -126°F (-70°C) at the stage of a stable phase condition of cement stone. At the stage of unstable phases, owing to weak bonds of water molecules that are depolarized with chlorine ion and weak bonds of the reaction products, nitrate ions come to react, and the sequence of these reactions is determined by their inherent chemical activity, alkali level of the solution and the intermediate reaction product - calcium aluminate - with which the following dissociation reaction is most likely. Please see this article about the KF-B micro-sewing effect on concrete cracks, https://www.kalmatron.com/files/Files1/Articles/KALMATRONKF-Bart.html NON-POLYMER BASED, VOC free. The 100% Waterproofing Cement Based Coating Kalmatron? KF-B Liquid Applied Membranes. No surface sealants are needed. Pigment can be added KF-B penetrates into concrete & masonry so that even if it is chipped off, that surface will still be completely waterproof applied by Brush, Roll, Spray or Mortar gun Stops seeping leaks in Basements, Garages, Pools,Tunnels, Ceilings, Walls, floors & Foundations. www.kalmatron.com
B.E Civil Engineer | AMIE | Chartered Engineer | Gov. Registered valuer under IBBI |Technical sales Manager | Waterproofing & Epoxy Flooring Expert | Construction Chemicals /Building Materials Sales | Project Execution|
6 年Raja sir nice information!! Was looking for this one.