Sealants are chemical substances used to bond surfaces together and seal gaps and joints between them. They work to prevent air, moisture and debris from entering and passing through openings in materials. Sealants are fundamental to the completion of your project, they help to boost energy efficiency, boost aesthetic appeal and protect surfaces from contaminants.

Different Sealant Types

Acrylic Sealants

Acrylic sealants are water based formulas which are typically used for sealing gaps and joints in doors, woodwork and trim. They are UV stable meaning that they are suitable for exterior applications, in areas where low movement is required. The limited degree of elasticity means that over time, movement may cause cracking. The sealant is however, paintable and provides a smooth finish, so can be colour matched to the surface

Butyl Sealants

Butyl sealants have a rubber-based formula, that does not typically cure like other sealants, but retains a gum-like consistency which means they are very flexible. They adhere well to a range of different substrates and are widely used in sealing gutters, corrugated roofing and automotive windshield sealing. They are highly water resistant, but however are not abrasion resistant and so should not be used in areas of significant movement as the seals can tear.

Latex Sealants

Latex sealants have a water-based formula and are often referred to as a general purpose sealant. They are best suited for interior use, sealing gaps between doors, mouldings and in places where the gaps are small and the movement at the joint is minimal. Latex sealants are also paintable. The water-based formula, does mean that the sealant is prone to shrinking and so are not best used in high moisture areas.

Polyurethane Sealants

Polyurethane sealants have excellent adhesion properties with very little substrate / surface preparation. They have a high movement capability due to their flexibility and are abrasion and UV resistant. Polyurethane sealants are mainly used in industrial applications such as bridge building, gutters, pipes and car manufacturing.

Polysulphide Sealants

Polysulfide sealants typically contain more volatile organic compounds than other sealant types and so require a few additional safety measures for protection. They have a great degree of flexibility even at low temperatures and can even be applied underwater, which makes them an excellent choice to seal active leaks that require repair. Polysulphide sealants are often used in external walls, cladding, glazing frames and roofs.

Silicone Sealants

Silicone sealants are extremely durable and versatile materials. They offer a high degree of flexibility and water resistance, forming air and water-tight seals to prevent any water leakage while still remaining intact when subjected to contraction and expansion. Despite being water, chemical and UV resistant, one of the limitations of silicone sealants is that they have a tendency to gather dirt and are at risk to mould growth. The mould growth however, is not due to the formulation of the product but to the high moisture areas that they are applied.

Factors to Consider

When it comes to choosing a sealant for your project it is fundamental that you pick the right formula for your needs. It is important to research prior to buying in order to make sure you are able to make an informed decision on the product. Choosing the wrong sealant may not pose a problem straight away but may arise as an issue later on, diminishing the longevity of your work.

• Your project needs - Think about what it is that requires sealing and what area and environment it is in.

• Surface compatibility - Different sealants adhere best to different materials so it's crucial to consider the sealant’s compatibility with the surface you will be joining. 

• Environmental factors - It is important to think about UV exposure, moisture and humidity levels, temperature changes and how these may impact the performance of your chosen sealant.

• Flexibility requirements - For joins that require movement or expansion it is important to consider the flexibility of the sealant as some may crack and shrink under movement which will create gaps, making your work ineffective.

• Paintability - If the sealant is being used in a visible area you may want to consider choosing a formula that can be painted over, so it is able to match your existing colour scheme

• Specialised formulas - Some sealants have additional features such as: mould resistance, quick-drying or may be especially formulated for specific surfaces which may be more effective than standard sealants.

Benefits of Using Sealants

Sealants are used to join surfaces together and seal joints in order to inhibit airflow and moisture from getting into your fixtures.

Here are some of the key benefits of sealants:

Durability - Sealants can withstand temperature fluctuation, UV and chemical exposure, which makes them good for use in harsh environments.

Aesthetic - The paintability of some formulas means sealants can be colour matched to your existing colour scheme, creating a seamless and clean appearance.

Waterproofing - Sealants create watertight seals in areas prone to high moisture and humidity, which helps to protect bathroom fixtures from water damage and mould growth.

Ease of Application - The application of sealant is both quick and easy, reducing the time and labour that is typically required for other traditional joining methods.

Energy Efficiency - Sealing gaps and cracks in your fixtures will improve the insulation in your home, reducing heat loss in the winter months and heat gain in summer months, which will help to reduce your energy and electricity bills.

Common Applications

Sealants play an essential role in the construction and renovation industry, they have a multitude of uses and can be used to prevent any leaks, repair cracks or gaps and promote structural integrity.

Here are some of the other common applications of sealants:

• Sealing gaps around windows and doors

They form an air and watertight barrier in the joints around windows and doors. This prevents draught, water leaks and noise penetration.

• Filling concrete joints and cracks

Used to seal cracks and gaps in concrete structures, in bridges, floors and walls. This prevents any water leaks, chemicals or debris getting into the concrete which may cause further damage and degrade the concrete.

• Sealing bathroom and kitchen fixtures 

Sealants are used to create watertight seals around bathroom and kitchen fixtures, this inhibits leaks, water damage and mould growth.

• Roofing

Used to form waterproof seals in skylights, chimneys and vents, which will help to prevent any leaks. Sealants are also used to seal any joints, seams and flashings.

• Masonry Restoration

Sealant is used to repair concrete and masonry, filling any cracks and gaps, providing structural reinforcement and preventing any further damage.

Maintenance and Longevity

It is important to maintain the condition of your sealant to prevent unwanted air and moisture from entering the vulnerable areas of the building. Deterioration of the sealant can not only be an eyesore as it becomes discoloured and marked, but can lead to leaks and mould growth. Having to repair and replace your sealant can be time consuming and costly and so it is important to regularly inspect and take care of your sealant joints.

Steps to Maintain your Sealant

Regularly inspect your sealant joints 

Examining the sealant joints is important to identify the early signs of damage so that it can be treated as quickly as possible. Here are some factors you should look out for when inspecting your sealant: 

• Cracking
• Discolouration
• Sealant separating from the surface
• Hardening
• Splitting

Clean sealant thoroughly 

It is essential to regularly clean your sealant so they remain free of any debris, mould and mildew. Not only will this be an aesthetic benefit, but in some formulas the buildup of dirt may impair the sealant’s ability to function.

Touch-Ups 

Repairing minor gaps and cracks in the sealant is not a long term solution, but can be used to prolong the life of the existent sealant until a more permanent solution can be put in place. It is important to remember that applying new sealant over existing sealant, will result in an inferior seal compared to applying fresh, new sealant.

Replacing damaged sealant 

When a large area of sealant is displaying signs of damage and failure, you should consider removing and replacing the sealant to prevent any damage to your fixtures.

Sealant inspection and maintenance will be individual to each formula and area of the home. As there are many different types of sealant, there are various different factors that will affect the sealant in your home, and may affect some areas more than others. The action required depends on the inspected condition of the sealant.

You should be looking to review sealant maintenance every one to two years.

Tips for Proper Application

Proper sealant application is important to ensure the longevity and effectiveness of the bonding between joints.

Here are some tips to make sure you get a neat and professional finish on your sealant:

Surface Preparation

Make sure that the surface you are applying the sealant to is properly cleaned and dried before applying the sealant. You should use soapy water to clean the surfaces and on non-porous surfaces you may want to take some methylated spirit to degrease the surface. If not done already, prior to applying new sealant you should remove any old, existing sealant.

Cut the Nozzle

When preparing the sealant cartridge, make sure to cut the nozzle at a 45° angle for ease of application. This allows you to get as close to the join as possible. The width of the opening of the nozzle should be slightly smaller than the joint you are sealing.

Constant speed and pressure

When using a sealant gun it is important to maintain an even pressure and  continual working speed to produce a constant bead of sealant.

Use a sealant smoothing tool

Once the sealant has been applied, you should use a smoothing tool to wipe over the seal and ensure the sealant is shaped into the joint. To avoid the sealant from sticking to the smoothing tool you should wet it with warm, soapy water.

Cleaning up

Once the sealant has been applied, it is important to wipe away and clean off any excess sealant for both aesthetic purposes and to prevent any damage to your fixtures when trying to remove hardened sealant.

Conclusion and Final Thoughts

Sealants are a fundamental component in construction and renovation projects. They provide protection and durability to your fixtures, improve your home’s energy efficiency, and aesthetically, give the finishing touches to your home. Choosing the right sealant and applying it correctly can have a significant difference in the results of your project.