What is a waterproofing sealant?

A waterproofing sealant is a polymer-based protective coating that is most commonly found in paint, concrete and masonry.


When applied to surfaces made of concrete or masonry, the waterproofing membrane forms a film barrier on the substrate, which prevents rainwater from penetrating through it. In case there is already water seeping through, the waterproofing membrane acts as a protective barrier that prevents further penetration of water into the substrate. Sealants are the ideal method to close unwanted openings between spaces when other materials such as concrete, mortar or timber are unable to do the job.



Waterproofing Sealant Application via Rope Access

Uses for Waterproofing Sealant

Sealants have a wide variety of uses and are a commonly used method in waterproofing in and around buildings.


They can be used in:

  1. Basements and foundations: to prevent the seepage of groundwater and moisture

  2. Pools: to help protect against corrosion caused by water

  3. Rooftops: to protect against rainwater that might seep into the building due to cracks

  4. External building facade: To prevent rainwater from entering the building due to cracks on the building's external surface.

Types of Waterproofing Sealants

There are many sealants available in the market, all made from different materials and each serving its own purpose. In general, there are 5 common sealant types and their corresponding use case

  1. Silicone sealants This type of sealant comes in a liquid form that resembles a gel. It is popular due to its flexibility, durability and ease of application through the use of a caulk gun. It is a form of adhesive commonly applied to windows, bathtubs, vents, sinks and roofs to prevent water leakages from entering buildings.

  2. Floor sealants As the name suggests, floor sealants are typically applied to vinyl flooring to protect the porous surface. It is a polymer-based coating that is easy to apply and is highly durable. Applying floor sealants extent the life of floors and other surfaces by reducing wear and tear and water damage.

  3. Polyurethane sealants Polyurethane is a type of organic material typically used to seal joints between materials. This sealant is used in areas such as joints of roof gutters, rainwater pipes and joints between precast concrete blocks. This sealant is used for joints as they are inflexible and durable, ensuring that joints do not shift and form gaps over time.

  4. Co-polymer sealants This sealant is used for non-porous surfaces such as tiles, glass or metal. The sealant comes in a clear finish which allows the underlying material to maintain its aesthetics. Co-polymer sealants can also be mixed with various types of paint when applying a paint layer to add an additional layer of waterproofing protection. Another feature of co-polymer sealants is their anti-mould properties, making it an ideal sealant for areas where mould is likely to grow such as basements and damp areas of the building.

  5. Bituminous sealants Bituminous sealants are made with bitumen-based solvents and are used for glueing and sealing cracks. They have UV-stable properties, can withstand high pressure and temperatures, making them a popular option for outdoor concrete surfaces.


Do Waterproofing Contractors use Sealants?

A waterproofing contractor provides various solutions for waterproofing and foundation repair. Sealant applications are one of the ways that waterproofing contractors perform to prevent leakages. They create effective waterproof coating systems that protect surfaces from the seepage of river or pond water, groundwater, atmospheric precipitation, and surface ponding.

Due to the high demand for waterproofing services, a lot of contractors have begun providing these services. However, not all of them possess the right qualifications/ licenses required and may even provide lower quality products or solutions that damage your property in the long run. An experienced waterproofing contractor is able to diagnose and suggest the proper sealant for the repair at hand.

Finding a Reputable Waterproofing Contractor in Singapore


So, how should you go about finding a waterproofing contractor in Singapore to assist me with sealant application? Here are some things to keep in mind:

  1. Ensure that they are experienced: ask for their portfolio and specific references to the repairs that are similar to yours.

  2. Ask them about the exact solutions they provide: some contractors may not be familiar with various types of building materials, so if they give you incorrect information, you could end up wasting your money causing more damage to your property.

  3. Ask for their licenses: only legal firms should possess the appropriate permits.

  4. Look into their customer reviews: these could provide an insight into what other customers think of their services.

Hydro-seal Technician Inspecting Sealant Application

Ensuring Sealant Application Is Properly Applied

During installation and application of sealants, make sure:

  1. The product used is specific to your requirements: your contractor should provide you with a list of materials and their function

  2. The surface is prepared: all loose, flaking particles are removed

  3. No cracks: the coating must form an airtight seal on your substrate

  4. The touch dry time: this refers to how much time it takes for the solution to set. It usually takes several hours for a sealant to set

  5. The application: the contractor should have proper training, necessary tools and equipment

  6. The applied material: you should check if there are visible defects in the coating, weak spots, or pinholes. These could cause deterioration over time.

Maintain Waterproofing Solutions

After installation, your contractor should provide you with recommendations on how you can help maintain the integrity of your solution. Some tips include:

  1. Asking them to inspect the sealant every few months: this helps ensure that there are no cracks or pinholes in it

  2. Cleaning: regular cleaning helps prevent the growth of mould and mildew

  3. Evaluating: you should be able to assess if there are any signs of damage in the sealant, which could indicate that it needs to be repaired

  4. Waterproofing is crucial in protecting your property against the penetration of water. It could help prevent building deterioration and costly repairs, as well as reduce the risk of mould growth and insect infestation within your property. When choosing a waterproofing contractor in Singapore or anywhere, make sure to look for an experienced contractor who possesses appropriate licenses and certifications – this way, you can be sure that they know what they are doing.

Contact Us - Singapore's Leading Waterproofing Contractor


Hydro-seal Engineering has specialised in waterproofing and rope access in Singapore since 1995. From residential projects to large industrial and commercial buildings, our team has almost three decades of experience providing long-lasting, high-quality solutions. Give us a call at +65 6289 6811 or send us a message, and our top-notch customer service will get back to you in no time.