Mastic sealants: The perfect multitasker 

No matter if you are working on sinks, toilets, skirting boards or dado rails, mastic sealant is a great all-round solution for dealing with them all. Discover more in our handy guide.

What is mastic sealant used for?

Whether you need anti-mould sealants for your shower & bathroom, all-purpose sealants for general use in the home or exterior sealants for roofs, gutters and frames, mastic sealant can do them all. It creates a strong, flexible and waterproof seal, making it ideal for sealing gaps and joints in places where it will need to resist some movement, such a shower screen or a window frame. Because exterior mastic sealant is weatherproof, it is also perfect for outdoor projects.

Mastic sealant: How to use it

Using mastic sealant is a simple procedure that anyone can master. Just follow these steps to create the perfect seal for all your home DIY projects.

1. Clean. To guarantee the best seal, ensure the area and surfaces you are working with are clean and clear of any foreign objects, such as dust or debris.
2. Prepare. For the best, safest results, ensure the area you are working in as well-ventilated (if it is indoors) as possible, and use gloves while applying the mastic sealant.
3. Prime. Most mastic sealant products come with an applicator nozzle, which you attach to the main tube after removing the cap and inner seal. Establish the bead size you wish to apply and cut the top of the nozzle to match that measurement.
4. Apply. Load your mastic sealant product into a caulk gun and squeeze the trigger gently to apply a consistent bead into to joint or gap you are working with.
5. Profile. Before the bead has dried, use a smoothing tool like the UniBond Sealant Finishing Tool to smooth it over and force it into the joint or gap to form the best seal possible. This will also remove any excess sealant, which can be scraped off in stages while smoothing the bead over.
6. Dry. Once the bead is smooth and in place in the joint or gap, leave to dry as per the instructions on your mastic sealant product.

Mastic for sealing ductwork

If you have a Heating, Ventilation and Air Condition unit (HVAC) installed, you’ll need to fill around the joints, otherwise an air loss in the system could occur. A water-based mastic duct sealant is preferable to tape: since it’s fluid you can reach areas that tape cannot. Also, its flexibility will withstand varying temperatures.

Selecting the mastic sealant you need

Choosing the right mastic sealant depends on what you are trying to achieve and what area of the house you are working in. If you need a genuine all-rounder for multiple jobs, UniBond Universal Sealant provides a strong, flexible and lasting seal for non-paintable joints in and around the home.

For projects where running water will be present, Unibond Triple Protection Anti-Mould Sealant repels and prevents mould, so your shower, bathrooms & kitchen remain in great condition. With a 35-year guarantee, it was rated ‘best in class’ for anti-mould protection in independent tests.

If you want an exterior mastic sealant: UniBond Window & Door Frame Sealant is a silicone mastic sealant, providing a flexible perimeter seal for exterior window and door frames. As well as outstanding adhesion to wood, uPVC, polycarbonate and metal, it won’t stain sensitive surfaces such as natural stone and marble.