Business Details
50+ Years
experience
Trusted Roofing Solutions in London
Guaranteed Asphalt has been a leading roofing company in London since 1963, establishing itself as the UK's sole manufacturer and installer of mastic asphalt and rubberised hot melt systems. Our expertise spans built-up felt, living roofs, single-ply membranes, and liquid applied coatings, offering tailored solutions for commercial, residential, and historic projects. With over five decades of experience, we have evolved alongside industry advancements while maintaining our commitment to quality and innovation. Our credentials include Safe Contractor, Construction Line, Achilles CHAS, and BBA accreditations, underscoring our adherence to rigorous standards. We prioritise cost-effective, durable roofing solutions aligned with modern construction demands, particularly for public sector contracts.Our team combines technical proficiency with a deep understanding of evolving waterproofing needs, ensuring clients receive reliable, future-proof systems. Headquartered in London, we serve projects nationwide, from iconic landmarks like 20 Old Bailey to educational institutions and healthcare facilities. Our technical data, design resources, and certifications demonstrate our dedication to transparency and excellence. By integrating traditional expertise with cutting-edge materials, we deliver roofs that balance performance, sustainability, and longevity. Our long-standing reputation is built on delivering complex projects efficiently, meeting tight deadlines without compromising quality.
Services
Mastic Asphalt Roofing
Hot Melt Systems
Living Roofs
Liquid Applied Coatings
Single-Ply Membranes
Built-Up Felt
GuaraFLEX Solutions
GuaraTEC Systems
GuaraGREEN Living Roofs
GuaraBOARD Insulation
Details
- Year established: 1963
Highlights and features
- We have over 60 years of specialist roofing experience since 1963.
- We are the UK's sole manufacturer and installer of mastic asphalt systems.
- Our technical expertise covers all major roofing membranes and applications.
- We hold industry-leading accreditations including BBA and Safe Contractor.
- We deliver nationwide projects from our London base with guaranteed supply chains.
Associations and certifications
- Safe Contractor
- Construction Line
- Made in Britain
- Achilles CHAS
- BBA
Services
Mastic Asphalt Roofing
Our proprietary mastic asphalt systems combine traditional craftsmanship with modern formulation for exceptional waterproofing. Ideal for flat roofs requiring long-term durability, these solutions are particularly suited to public sector projects where cost efficiency and longevity are critical. The material's flexibility accommodates structural movement while maintaining watertight integrity.
Living Roofs
GuaraGREEN living roof systems integrate vegetation with waterproofing layers to create sustainable urban ecosystems. These solutions enhance biodiversity, improve thermal performance, and manage rainwater runoff. Our designs comply with BS 6229 standards, balancing ecological benefits with structural protection for commercial and residential buildings.
Liquid Applied Coatings
Cold-applied liquid membranes form seamless protective layers for complex roof geometries. Our systems cure rapidly to create durable, UV-resistant surfaces suitable for both new builds and refurbishments. The solvent-free formulations meet environmental regulations while providing excellent adhesion to various substrates including metal and concrete.
Single-Ply Membranes
High-performance single-ply membranes offer lightweight, flexible waterproofing solutions for modern construction. Our TPO and EPDM systems feature factory-controlled quality, rapid installation, and exceptional weather resistance. These membranes are ideal for large commercial roofs requiring minimal maintenance over extended service life.
Hot Melt Systems
GuaraTEC hot melt systems utilise advanced polymer-modified bitumen for fully bonded waterproofing. The molten application ensures complete substrate adhesion, eliminating voids and capillary action risks. These systems excel in high-traffic areas like car parks, offering superior crack-bridging capabilities and chemical resistance.
People
David Boyd
Designer
David Boyd leads design projects at Guaranteed Asphalt, combining technical expertise with creative problem-solving. With 15+ years in roofing design, he specialises in integrating waterproofing solutions with architectural requirements, ensuring both functionality and aesthetic compliance.
Garo Susmanyan
Senior Designer
Garo Susmanyan oversees complex design implementations, bringing 12 years of specialist roofing experience. His expertise in BIM integration and technical detailing ensures precise execution of challenging projects, from historic restorations to modern commercial developments.
Henri Taylor
Estimating Director
Henri Taylor manages cost estimation and project planning, leveraging 18 years in construction procurement. His strategic approach balances competitive pricing with technical accuracy, ensuring transparent budgeting for clients across public and private sector contracts.
Questions
What roofing systems does Guaranteed Asphalt specialise in?
We specialise in mastic asphalt, rubberised hot melt, single-ply membranes, liquid applied coatings, and living roofs, offering comprehensive solutions for all building types.
Are you certified for public sector contracts?
Yes, our Safe Contractor, Construction Line, and Achilles CHAS accreditations qualify us for all major public sector procurement frameworks.
Do you provide technical documentation?
Yes, we offer full technical support including NBS specifications, BIM models, data sheets, and warranty documentation through our website.
How long has Guaranteed Asphalt been in business?
We've been delivering roofing solutions since 1963, with our first contract completed in November 1963.
What areas do you cover?
While based in London, we operate nationwide across the UK, completing projects from Edinburgh to Cornwall.
Do you offer warranty options?
Yes, we provide comprehensive warranty packages through our Alcumus and BBA certifications, with terms up to 20 years depending on system selection.
Reviews (3)
Jean-Baptiste G.
Nov 13, 2020
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Guaranteed Asphalt was mandated to inspect the roof of my property following a leak. On the first appointment they did not show up, no notice and no apologies. On the second appointment they arrived late, checked the leak within my house, told me they would go get the ladder from their car to inspect the roof, but never came back. When I asked why they did this, they replied the leak could not come from the roof, without checking the roof. Later, another contractor came and found gaps between the roof and the gutter, and between the drainage pipe and its passage within my roof, which, should these be sealed properly, would not let water in. My roof was installed by Guaranteed Asphalt. If you are looking for professional roofers, with strong work ethic, and non-lazy staff, pick a different company.
Dominic Ellis
Jan 29, 2017
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Excellent flat roofing company, would recommend, both manufactures and installs felt, hot melt and asphalt roofing as well as green roofs, multi story car parks, podiums, balconies, etc.
David Jones
Jan 16, 2016
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The best service possible. Our project was seen through from start to finish. I can't speak highly enough. And Jackie Hards in accounts was very helpful through out.
