What is a Waterproofing Membrane?

23 Oct What is a Waterproofing Membrane?

How Water Penetrates Your Building

“Flow like water” – we often compare fluid movements of objects to that of water. Similarly, in situations of water ingress, water has a highly adaptive capability to penetrate buildings from multiple points. This ranges from leaking pipes to roof leakages, from basement dampness to bathroom grout wear and tear.

Any water that enters your building or home poses a threat. In fact, 80% of all building defects can be attributed to water penetration related issues. Water ingress causes both immediate and long-term problems if left unaddressed. These problems vary from fungal decay to health issues arising from damp.

How then can building owners prevent or reduce water penetration? The answer lies in waterproofing membranes.

In Short, a Waterproofing Membrane is

A thin layer of waterproofed material that is laid on building surfaces to prevent water ingress or penetration. They are instrumental in protecting the foundation structures from water damage and decay.

This is our Comprehensive Guide to Waterproofing Membranes

To help readers understand which membrane and what application method should be used, we have created a comprehensive guide to waterproofing membranes. We first start by looking at the different waterproofing membrane systems.

Types of Waterproofing Membrane Systems

Waterproofing membranes come in different forms, each with their own pros and cons. To understand how waterproofing is done, it is essential to first comprehend the differences between each type of membrane.

Sheet Membrane Systems

Sheet Membranes Systems involve the laying of standardised sized membrane sheets. Having been manufactured before actual application, sheet membrane systems boast precise consistency in terms of thickness and durability.

When used in wide open areas such as flat roofs, this type of system shines best, allowing professionals to quickly cover large surfaces. However, for less open areas, waterproofing professionals are required to handle, cut, install and detain the membrane sheets. This makes the system relatively less flexible in its application.

In addition, membrane sheets need to be joined at the seams where by they overlap or connect. This is done through the torching of the seams to bond the sheets. The flaws of this approach lie in the possibility of the seal breaking over time. In this event, not only would water would naturally penetrate the surface but also, it would be trapped under the sheets, causing a rapid compromise of the entire waterproofing system.

Liquid Membranes Systems

The flip side of sheet membranes are liquid membrane systems. Liquid membranes have no predetermined form, thus allowing the contractor to apply it as they see fit. They can be used on most surfaces, regardless of shape. Application is done via brush or rollers, with multiple coats often used to eliminate air pockets. After which, the membrane should be left to cure.

The trouble with liquid membrane systems lies in the time and effort needed to finish the entire application process. Furthermore, the skill of the contractor is pulled into scrutiny as proper coats of the membrane need to be laid down.

The flexibility of liquid based membrane systems make it a superior product to sheet based membranes, however the slower rate of application handicaps the product in open spaces.

Spray-On Membranes Systems

Spray-on membrane systems utilise liquid membranes but have a modified method of application. Instead of brushes or rollers, highly resistant solvent free polyurethane spray-applied systems are used instead to lower the labor intensiveness of the process. Time is reduced as more membrane is applied per time unit as compared to liquid membranes.

However, the aforementioned strength of spray-on membrane systems is also its weakness. Sprays challenge users to achieve uniform finishes given the variation introduced by broadness of the scattered approach. To overcome the risk of uneven finishes, testing should be performed before actual application. Additionally, experienced spray-applied professionals should be engaged to minimise the risk of gaps in the membrane’s layer.

Different Methods of Application

Other than systems of waterproofing membranes, different methods of application also exist. Factors such as exposure to sunlight, being above or below ground level and whether the surface is weather facing are involved here.

Positive & Negative Side Membranes

Positive side membranes are applied on the side of a surface that faces hydrostatic pressure (e.g. rain). It acts as the first line of defence to stop water penetrating into the building. Additionally, it protects concrete and other materials from foreign substances.

Negative side membranes are applied on the opposite side, acting as a secondary defense. It prevents moisture that has bypass the positive side membrane from leaking into the building. In areas where positive side membranes cannot be applied to the outward facing surface, negative side membranes can be set up internally to minimise the amount of water ingression.

Sub-grade & Above-grade Waterproofing

Sub-grade waterproofing are areas where a waterproofing membrane is applied below the building’s ground surface level. Typically, this includes lift pits, tunnels, retaining walls and under-slabs. Its most outstanding characteristics would be the ability to withstand constant contact with soil moisture and roots.

Above-grade waterproofing areas are found above the ground surface. Commonly, these include balconies, internal wet environments and planter beds on suspended slabs. Unlike sub-grade areas, above-grade areas are exposed to a variety of elements. Instead of the presence of constant soil moisture, forces that act on above-grade areas include strong sun, heavy rain and other foreseeable elements.

Exposed & Non-Exposed Systems

Non-exposed systems are typically below-grade or between slab-floor finishes. In this system, the water membrane is hidden from view and cannot be reached without extensive renovation or construction works. As such, the membrane needs to be sufficiently robust and durable to withstand water penetration for decades without maintenance.

Exposed systems are exposed to elements such as ultraviolet light, rain, chemicals and pedestrians. Due to the degree of forces landing on these membranes, they require regular maintenance to keep them in working condition.

In Conclusion

A variety of factors affect the choice and application of waterproofing membranes. Depending on the forces anticipated to act on the membrane, its ease of accessibility, and time available for applying, different materials or techniques will have to be employed. Furthermore, the skill of the contractor or user is critical in waterproofing.

Choose ProSeal Contracts for Your Waterproofing Needs

ProSeal Contracts is a waterproofing company in Singapore with more than 20 years’ experience. As one of the leading waterproofing contractor companies, we use the highest quality of materials to ensure long lasting results. Trust us to assess, choose and apply the right waterproofing membranes for your building’s needs.