Business Details
50+ Years
experience
Emergency
services
Trusted Sealant & Waterproofing Contractors in London
County Mastics has been a trusted name in mastic sealant application, waterproofing, and firestopping for over 40 years. Established in 1972 as a family-run business in East London, we have grown to become a leading contractor serving domestic and industrial clients across London and the surrounding counties. Our expertise spans iconic projects such as 10 Downing Street, Windsor Castle, and the Westfield Centre in Stratford City, demonstrating our commitment to quality and precision. With a team of highly experienced applicators, many of whom have been with us for over two decades, we combine traditional craftsmanship with cutting-edge materials to deliver durable, high-quality solutions. Our services include external and internal sealing, high-build applications, firestopping, and natural stone joint sealing, tailored to meet the demands of both small-scale residential and large-scale commercial projects.We are certified by industry bodies including the Association of Sealant Applicators and the International Powered Access Federation, underscoring our adherence to safety and professional standards. Our sister company, County Construction Chemicals, ensures access to advanced sealant technologies, enabling us to provide comprehensive solutions for every client. Available 24 hours a day, six days a week, we prioritise reliability and responsiveness, ensuring minimal disruption to our clients' operations. With a proven track record in sectors ranging from government buildings to leisure centres, we remain dedicated to excellence in every project we undertake.
Services
External Sealing
Internal Sealing
Firestopping
High-Build Applications
Natural Stone Sealing
Details
- Year established: 1972
Highlights and features
- We have over 40 years of experience in specialist sealant application.
- Our team includes certified applicators with decades of industry expertise.
- We work on iconic projects including 10 Downing Street and Windsor Castle.
- Our 24-hour availability ensures minimal disruption to client operations.
- We use advanced materials from trusted manufacturers like Fosroc and Sika.
Associations and certifications
- Association of Sealant Applicators
- Health and Safety Scheme
- Association of Passive Fire Installers
- International Powered Access Federation
- Construction Skills Certification Scheme
Services
External Sealing
We specialise in sealing expansion joints between brickwork, concrete, and UPVC for roadways, roofing, and swimming pools. Our solutions prevent water ingress and structural damage using durable silicone and polyurethane materials. Ideal for new builds and refurbishments, this service ensures long-term protection against weathering.
Firestopping
Our firestopping services include installing fire batts and intumescent sealants to achieve 2-4 hour fire ratings. We seal frames, perimeters, and high-temperature areas like oven doors, meeting building regulations and safety standards. This service enhances structural fire resistance for commercial and residential properties.
Natural Stone Sealing
We apply premium, non-staining silicone sealants for natural stone joints in cladding and flooring. Our methods protect against chlorine and salt exposure, preserving aesthetics and durability. Suitable for heritage sites and modern developments requiring precision stone sealing solutions.
High-Build Applications
Our high-build sealing covers cradle work, roofing, and glass-to-glass joints using IPAF-certified cherry-pickers and rope access. This service addresses complex areas inaccessible by traditional methods, ensuring watertight and durable seals for industrial and commercial structures.
Internal Sealing
We provide waterproofing and sealing for kitchens, bathrooms, and cleanrooms using mould-resistant silicone. Our solutions integrate with fitted storage, skirting, and sanitaryware, offering both functional and decorative finishes tailored to residential and commercial interiors.
Questions
What areas do you serve?
We operate across London and the surrounding counties, including Essex and Hertfordshire.
Do you handle emergency sealing work?
Yes, our applicators are available 24 hours a day, six days a week for urgent projects.
Are your applicators certified?
Our team holds certifications from the Association of Sealant Applicators and IPAF, ensuring safety and expertise.
What materials do you use?
We use premium sealants from manufacturers like Fosroc, Sika, and Dow Corning for durability and performance.
Can you work on listed buildings?
Yes, we have experience sealing historic structures like Windsor Castle, using sympathetic materials and methods.
Do you offer free site visits?
Yes, we arrange free site assessments to determine the best sealing solutions for your project.
