Waterproofing Membrane – Types, Application & Selection


Introduction:

Buildings can be severely harmed by water. If the foundations are not appropriately waterproofed and secured, this damage can result in severe financial loss as well as safety concerns. Waterproofing membranes, on the other hand, can be used to prevent this. Waterproofing membranes are beneficial to all commercial, industrial, and residential facilities.

Sometimes during construction, the waterproofing component is omitted completely or it is provided of very low quality for which each year many commercial premises and residential properties report water damage. Experts say that 80% of building defects come from water-related issues.

What is Waterproofing Membrane?

A waterproofing membrane is a water-tight layer of material that is put to a surface to keep water out and prevent damage. The most popular types of waterproofing membranes are liquid applied or pre-formed sheet membranes.

To prevent water infiltration, they can be attached or erected around the foundations (much like a structural slab). Waterproofing will help to stop water infiltrating from the foundation and safeguard our property from water damage, whether it’s for our building’s basement or roof.

Waterproofing has become important for the basement, walls, bathrooms, kitchen, balconies, decks, terrace or roofs, swimming pools, water tanks, etc.

Waterproofing Membrane
Courtesy: Sika Group

Application Of Waterproofing Membrane:

Waterproofing membranes are most commonly used in the following areas:

  • Water tanks
  • Plant rooms
  • Garden beds
  • Retaining walls
  • Balconies and podiums
  • Water tanks/basements
  • Flat roofs (including green roofs)
  • Containment and bounded areas

Types Of Waterproofing Membrane:

Waterproofing membranes can be classified broadly into two categories.

1. Sheet Based Waterproofing Membrane

Sheet-based waterproofing membranes are available in the form of rolls. These are first unrolled and then laid on a firm surface. One of the most commonly used sheet-based membranes is the bituminous waterproofing membrane.

Using blowtorches, this type of membrane adheres to the substrate with a hot tar-based adhesive. The same hot adhesive is used to join adjacent membranes together. To produce a waterproof junction, the sheets are overlapped by roughly 100mm (4″) each.

Some membranes are even linked by melting them with a hot air pistol and then overlapping them on the sheet that was previously deposited. Joints between sheets are crucial with this type of membrane, and they must be done correctly to avoid leaking.

Bottom of the membrane is being heated using a blowtorch
Source: rajeshinfrastructure.com

PVC membranes and composite membranes are two more types of sheet-based membranes. The latter has a fabric foundation that gives strength and tears resistance, as well as a chemical coating that provides resistance. Except for the joints, sheet-based membranes are factory-produced so they are consistent in quality.

2. Liquid Applied Waterproofing Membrane

Liquid applied waterproofing membranes are those that are applied to a surface as a liquid that can be sprayed or brushed on. The liquid produces a monolithic membrane with no laps, welds, or seams when sprayed.

By applying more liquid chemicals per unit area, the thickness can be regulated. The application procedure of this type of membrane is very quick. To avoid cold joints, contractors generally try to finish the entire area to be waterproof in a single day.

But cold joints can be easily done for a very large area by overlapping the new membrane over the old. In this process, the chemical will stick to itself readily. Because they are joint-free, they are typically thought to be better than sheet-based membranes.

Liquid applied waterproofing membrane
Liquid applied waterproofing membrane
Source: archiproducts.com

However, before applying it, care must be taken to ensure that the thickness is precisely correct. If the membrane is too thin, it can rip or break. The membrane’s adherence to the concrete must be excellent.

Some special types of waterproofing membranes are:

1.  Polymer-modified Bitumen Membrane

Polymer bitumen roll fed sheet membrane is one of the most widely used waterproofing membranes. These are also used as an underlay for pitched roofs as a vapor barrier.

The material withstands temperature fluctuations and high mechanical loads providing long-term, reliable and effective waterproofing. The polymer-modified bitumen sheet membrane provides additional flow resistance that makes it possible to use the material in a very hot climate.

On the bottom side, the material is covered by a polymer film with special graphic elements, melting of which indicates the proper material heating. On the top side, the material is covered by a polymer film.

2. Self-adhesive Modified Bituminous Membrane

Asphalt, polymers, and tackifiers are used to make self-adhesive modified bituminous membranes, which may also include mineral stabilizers. Fiberglass, polyester, or a combination of the two can be used to strengthen the items.

Mineral granules, coatings, films, and other opaque surfaces are commonly used on products designed to be exposed to the weather. A release film or paper protects the self-adhesive layer, which is removed during installation.

3.  Thermoplastic Membrane

Thermoplastic roof membranes are a good commercial roofing system. It is made up of polypropylene, ethylene-propylene, and polyester, and it’s frequently reinforced. UV absorbers, colorants, flame retardants, and other additives can be added to TPO sheets to create the desired physical qualities.

4. Polyurethane Membrane

It is a fiber-enhanced and water-based polyurethane membrane commonly used to cover tiles, screeds, concrete beds, etc.

5. Polypropylene Membrane

Bitumen is used to make a specific waterproofing substance. They are packaged in rolls. Each roll is 10 meters long and 1 meter wide, covering an area of 8.7 m2. It is a highly effective and long-lasting waterproofing substance that is employed in almost all buildings. On concrete flat roofs, it’s a common waterproofing material.

6.  PVC Membrane

It is a highly flexible sheet membrane system. It is used to protect concrete structures. It can range from conventional single-layer compartment systems to active control systems to suit the most stringent requirements.

They are fully bonded and provide excellent waterproofing safety and installation efficiency, making them ideal for basements and below-grade locations.

Selection Of Waterproofing Membrane

The selection of a perfect waterproofing membrane depends on some properties of the membrane. These are:

1) UV Stability

The membrane must be UV stable or UV resistant while exposed to the sun. If it is not, then it will degrade over time.

2) Elongation

Elongation means the ability to stretch. This property of waterproofing membrane helps to stretch over the cracks that may be developed in the future.in markets; membranes with elongation properties of over 200% are available.

3) Breathability

The membrane should be breathable. Some membranes are designed to keep water out while enabling water vapor to travel through them. Breathable membranes then allow trapped water to dissipate into the atmosphere over time.

4) Tear Resistant

The membrane should be such that it will not tear even if a reasonable force is exerted on it. There are many membranes that have good elongation and also can tear easily. So membrane should be tear-resistant.

5) Abrasion Resistant

This refers to a membrane’s ability to tolerate wear and tear. Because most membranes are coated with concrete screeds and tiling, abrasion resistance is important during the construction phase, when workers walk on the surface, drop nails and screws, and scrape hard things like rebar against the membrane, which can cause damage

6) Chemical Stability

The membrane should be chemically inert with respect to its environment in the building. Some membranes, particularly those on the outside of basement walls, are exposed to soil and moisture.

Also Read –

Methods Of Waterproofing For Building

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