Mastic Sealants

Choosing the right mastic sealant is a vital part of your project. ARBO Mastic sealants come in a variety of formulations, each designed for specific applications. Low modulus silicone sealants are ideal for expansion and drainage joints due to their flexibility and fast curing, while high modulus options offer excellent adhesion for glazing and aluminium sealing. Whether for HVAC ducting, roofline systems, or general maintenance, these versatile sealants deliver reliable performance.

If you can’t find the right sealant, get in touch with a member of our team and they can help you find the right sealant for you.

General Pointing and Perimeter Sealing
Arbomast GP, part of the ARBO mastic range is great for sealing around timber frames. It offers strong bonding, making it perfect for joints in traditional construction projects.

Concrete Panel Joints
This sealant is particularly effective for joints between preformed concrete panels, such as those found in garage constructions. Its flexibility accommodates the minor shifts typical in these structures. Low modulus silicone is often used as an expansion joint sealant in these applications, as it allows for movement and maintains waterproofing over time. The curing process is important here, as it determines the sealant's final properties and performance.

Paintable Finish
Arbomast GP can be painted over to blend seamlessly with surrounding materials, though a test is recommended due to varying paint systems.

Limitations
Experts do not recommend using Arbomast GP for joints that move a lot, natural stone, or indoor use. It is made for more stable outdoor applications.

Metal-to-Metal Sealing
Arbomast BR is made for creating watertight and airtight seals in metal joints. It works well for curtain walls and window assemblies, ensuring they close securely.

Lap and Fixing Joints
Effective for sealing between metal lap and fixing joints, Arbomast BR offers an essential seal but is not intended to add structural strength.

Bedding and Concealed Joints
Arbomast BR is suitable for a range of concealed joints, including those in timber, concrete, and metal structures, where a reliable yet non-setting sealant is needed.

Heating and Ventilation (HVAC) Ductwork
It also provides an effective seal for HVAC ductwork, ensuring that duct joints are closed tightly against air and water intrusion.

ARBO mastic sealants offer strong adhesion and long-lasting flexibility. They also resist weather well, making them perfect for construction and maintenance projects. Some of the key benefits of our sealant range include:

Versatility and Strong Adhesion
ARBO mastic sealants are highly effective at sticking to a wide range of common construction materials, including timber, concrete, and metals. This makes them a great choice for general construction projects. Arbomast GP is perfect for sealing around perimeters and concrete joints, while Arbomast BR works well for metal-to-metal joints and hidden bedding areas.

Durability and Pliability
These sealants maintain flexibility over the years, even after forming a surface skin. Arbomast GP and Arbomast BR are made to resist ageing and environmental damage.  Arbomast BR can last more than 20 years if it is kept out of direct sunlight

Effective in Various Temperature Ranges
The ARBO sealants work well in many temperatures. They can handle lows of -25°C for Arbomast GP and highs of 90°C for Arbomast BR which makes them good for both indoor and outdoor use in the UK climate.

Specialised Applications

• Arbomast GP: Recommended for sealing joints between concrete panels or timber frames and can be painted over for aesthetic integration, although pre-testing is advised.

• Arbomast BR: Provides excellent sealing for metal joints in curtain wall assemblies, window frames, and HVAC ductwork, ensuring watertight and airtight results.

Ease of Use and Compatibility
Both products come in user-friendly 380ml cartridges, compatible with standard caulking guns, and are supported by ARBO’s range of cleaners and primers for optimal performance on various surfaces. For porous or friable substrates, Arbo 925 Primer is recommended to enhance adhesion.

Compliance and Safety
Both Arbomast GP and Arbomast BR adhere to British Standards for joint sealing (BS 8000 Part 16), ensuring they meet UK building regulations and performance expectations. The products are also safe for handling, with no significant health hazards noted, although it is always recommended to consult the material safety data sheets.

Many ARBO sealants comply with relevant British Standards (BS EN ISO 11600, BS 5889) and offer additional assurances for use in construction. If you need a silicone sealant that complies with specific standards, speak to our team and they can suggest the best product for you.

Still not sure which product is right for your application? Talk to our expert team! We can provide advice on the right sealant for the type of surface, adhesion and elasticity required.

Important Information

The information is given in good faith and based on results gained from experience and tests. However, all recommendations or suggestions are made without guarantee since the conditions of use are beyond our control.

It is the user and specifier’s responsibility to ensure ARBO product is suitable for the intended use: consult ARBO Technical Services for specific advice. Goods are supplied subject to the Company’s terms and conditions of sales, a copy of which is available on request.