How to Waterproof Parapet Walls – Importance of Parapet Wall Waterproofing

As per our experience, many customers have frequently asked, why is it necessary to do the waterproofing of the parapet wall. Here we have tried to explain the importance of parapet wall waterproofing.

These days we have observed that many of the waterproofing applicators & vendors have adopted shortcuts to get the project or complete the work early. Also, it has been observed that such vendors/applicators try to take advantage of the lack of technical knowledge of the customers. This is definitely not the long-term waterproofing solution as they are focusing on terrace waterproofing while neglecting an important area of the terrace i.e., the parapet wall.

As we are already aware that concrete is formed through the combination of different materials like cement, fine aggregate (sand), coarse aggregate (stone), and water. One of the vulnerable properties of concrete in terms of waterproofing is that concrete has a lot of air gaps between its molecules which makes concrete porous in nature, hence easily exposed to water seepage.

Let’s take a look at parapet wall waterproofing in detail.

Parapet Wall Waterproofing

The parapet wall is also made of concrete and with due course of time, there are always a few cracks formed on it. During rain, the water enters the parapet wall through these cracks or by directly getting absorbed by the concrete surface. This seeped-in water then travels down in a vertical direction due to gravity and inside the horizontal slab surface resulting in seepage.

We have formulated three different cases for easy understanding of the concept:

Surface without waterproofing –

With due course of time, the terrace and the parapet wall both develop cracks because of which the water seeps inside the building resulting in seepage/dampness. 

In the above image, it can be seen that cracks have formed on both the parapet wall as well as the terrace/roof horizontal slab resulting in seepage of water

The water has entered into the terrace slab through the cracks formed in the parapet wall and on the horizontal surface resulting in the seepage.

Waterproofing on horizontal surfaces only –

This method is generally adopted by local waterproofing vendors in order to reduce their quotation, claiming that the work has been done by them at a lower cost. If the waterproofing is done only on the terrace slab and not on the parapet wall, it still results in the failure of the waterproofing. 

In the above figure, the waterproofing has been done only on the horizontal surface of the terrace.

It indicates that even though the crack on the horizontal surface is filled and waterproofing to the terrace slab is applied, the waterproofing has failed.

The reason for the waterproofing failure is:

1. The cracks on the parapet wall are left unattended
2. The water is absorbed by the parapet wall as there is no waterproofing layer to obstruct it.

It means, that even if the crack filling is done on the parapet wall, seepage will still take place, as the water will be getting absorbed by the parapet wall due to the unavailability of any barrier.

Proposed Solution

Our comprehensive waterproofing solution begins from the terrace slab down to the parapet walls for full protection against seepage. Therefore, we ensure creating a strong barrier by waterproofing inside and outside parts of the parapet walls, which are very liable to seepage from any side.

Our technique repairs the cracks and applies waterproofing not only to the horizontal surface but also to the parapet walls, as shown in this image, which can give zero seepage. It might be a little more costly initially, though the benefits will last much longer and be worth the additional cost, compared to conventional methods of waterproofing on a horizontal surface for maintenance-free terraces or roofs.

Things to Consider in Waterproofing Membrane for Parapet Walls

Waterproofing membranes protect parapet walls from water infiltration. They lay a protective layer to block seepage that may destroy the structural elements of your home parapet. While choosing a membrane, look for durability, UV resistance, and compatibility with the parapet roof materials. Proper parapet wall waterproofing ensures longevity and prevents costly repairs. Parapet waterproofing is important in maintaining a dry and safe environment inside your home.

Self-sealing around fasteners

• Avoid Water Infiltration: Self-sealing membranes around fasteners further protect by closely sealing around nails and screws to avoid water infiltrating your parapet walls.

• Durable and Flexible: These membranes are designed to maintain their integrity during the expansion and contraction of the parapet roof and for long-term waterproofing.

• Increased Protection: Self-sealing membranes are perfect for parapet wall waterproofing like in high-risk areas where fasteners penetrate the membrane.

• Easy to install: Self-sealing property makes installation easier with fewer chances of leaks in your home parapet.

Membrane designed for vertical applications

• Specially Formulated: These membranes are specially formulated and designed to cling tightly to vertical structures; thus, making them perfect for parapet walls.

• Stronger Adhesion: They have strong adhesion on the wall during bad weather conditions, ensuring effective waterproofing of the parapet.

• Resist Sag: The membranes are in a way that they won’t sag, and for that reason, they will remain on the parapet walls for constant protection.

• UV Resistant: For parapet roofs exposed to the sun, UV resistance ensures that the membrane doesn’t degrade over time.

Membrane material thickness

• Appropriate Thickness: The waterproofing membrane thickness is a crucial feature in terms of being effective on the parapet walls for maximum protection from water seepage.

• Resistance to Impact: Thicker membranes offer a higher resistance to impact, which is indeed very vital in safeguarding the parapet roof against physical damage.

• Increased Service Life: A thicker membrane prolongs the service life of your home parapet for longer periods.

• Protection against Severe Conditions: Done for places with extreme weather conditions, thicker membranes give increased protection for parapet wall waterproofing.

General Tips for Parapet Wall Waterproofing

• Select UV-resistant membranes for any kind of protection of the parapet walls from sunlight.

• Make sure to seal all the fasteners on the parapet roof adequately.

• Parapet walls are usually designed for vertical surfaces. So, it is better to use membranes designed for vertical surfaces.

• Using membrane thickness is something that can be considered to give more durability and protection in many aspects.

• Parapet waterproofing should be inspected and maintained to avoid leaks and damages.

Conclusion

Parapet wall waterproofing ensures the integrity and life of your house. A properly selected waterproofing membrane and its proper installation can save your parapet walls from water seepage that can cause structural failure and other very expensive repairs. High-quality parapet waterproofing not only protects your parapet roof and house parapet but also increases the overall durability and value of the property. Regular maintenance and a keen eye for detail in waterproofing parapet walls are indeed the two major steps in establishing a safe, dry, and durable barrier against water.