Asphalt Flat Roof Alternative
Asphalt has been used on flat roofs for decades, but over time it can become brittle, crack, and allow water to penetrate. We overlay existing asphalt roofs with the Ultraflex cold-applied waterproofing system, repairing cracks and creating a seamless, fully bonded membrane that remains flexible and dramatically extends the service life of your roof.
The problems with asphalt flat roofs
Asphalt is a traditional roofing material that hardens and degrades over time. Thermal movement and sun exposure take their toll, leading to the common failures below.
Cracks with age
Asphalt becomes brittle and develops alligator cracking and splits as it ages. Thermal movement opens these cracks further, letting water straight into the deck.
Melts in heat
Dark asphalt absorbs heat and can soften, slump or even run in hot weather. This distorts falls, creates ponding, and can leave the roof uneven and poorly drained.
Blisters and ridging
Trapped moisture and thermal movement cause blisters, ridges and surface distortions that eventually break open and leak.
Costly full replacement
Once asphalt fails, many contractors recommend a full strip. We can overlay it instead, saving the removal cost and disruption.
Poor UV resistance
UV exposure dries out the surface oils, accelerating brittleness and cracking across the whole roof area.
Drag the slider to see the transformation
Why we install our waterproofing system over asphalt
Asphalt cracks with age and softens in heat, making it a short-lived, high-maintenance flat roof. Our waterproofing system is a flexible, cold-applied liquid membrane that bonds directly over asphalt, sealing cracks and creating a seamless layer that moves with the roof - backed by a 20-year guarantee.
One of the best flat roof waterproofing systems on the market
Whatever flat roof job you have - installation, repair, replacement, Asphalt, GRP, EPDM or torch-on felt overlay - we install the Ultraflex cold-liquid waterproofing system. It's the most durable, cost-effective, and reliable flat-roof solution available.
By overlaying your existing roof with Ultraflex, we save you the cost and disruption of a full strip-out while delivering a fully bonded, seamless waterproof layer backed by a 20-year guarantee. We go in, repair your existing roof and seal it for decades of protection - if needed, we can apply bespoke finishes and solutions post-waterproofing.
Why we install Ultraflex on every job
Faster installation
Fast-curing and rainproof in as little as 30 minutes.
Up to 50% cost savings
Overlay your existing roof and avoid strip-out costs.
20-year guarantee
Proven waterproofing built for long-lasting protection.
100% Compatible
Torch-on felt, asphalt, GRP, timber, concrete, and virtually any roof surface.
Safer installation
Cold-liquid application, eliminating fire risk.
Seamless waterproofing
No joints or laps - a fully bonded waterproof layer.
How we work:
Instant Estimate
Fill out our cost estimate tool to receive a fast, ballpark price based on your project details. It's a quick way to understand likely costs before moving forward.
Site Visit + Detailed Quote
We carry out a site visit where needed to assess your roof in detail, then provide a clear, itemised quote with no hidden costs so you know exactly what to expect.
Installation
Our trained team prepares the surface and installs the Ultraflex system, delivering a seamless, fully bonded waterproof finish built to last.
Sign-off & 20 Year Guarantee
We inspect the roof, hand over your 20-year guarantee documentation, and leave the property spotless.
How Ultraflex compares
See how our Ultraflex cold-liquid waterproofing system stacks up against traditional flat roof systems across the things that matter most.
| Criteria | Ultraflex | GRP | EPDM | Asphalt | Torch-on Felt |
|---|---|---|---|---|---|
| Seamless, fully bonded | |||||
| Cold-applied (no flame) | |||||
| Rainproof in 30 minutes | |||||
| Overlay existing roof | |||||
| 20-year guarantee | |||||
| Cost-effective long-term | |||||
| Resists cracking & shrinking | |||||
| Suitable for complex detailing |
Ultraflex over existing asphalt is typically up to 50% cheaper than a full strip-and-replace, and it eliminates the cracking and heat-softening issues. Use our estimator for a personalised quote.
Why Ultraflex — FAQs
The most common questions we get asked about the Ultraflex cold-liquid waterproofing system.
Can you waterproof over an existing mastic asphalt roof?
In most cases, yes. Asphalt is one of the substrates the Ultraflex cold liquid system bonds to particularly well. We make good any splits, blisters and defective areas first, prime the surface, then apply a fully bonded reinforced membrane over the whole roof. A strip-out is only necessary if the insulation or deck beneath the asphalt has become saturated or structurally unsound.
How long does an asphalt flat roof last before it needs attention?
A well-laid mastic asphalt roof will often give twenty five to forty years of service. Signs it is reaching the end of that life include widespread surface crazing, splits along the falls, slumping or ridging, blistering, and ponding water that no longer drains within a day or two of rainfall.
Why does my asphalt roof crack in summer and leak in winter?
Heat drives the failure and cold reveals it. Sun exposure dries out the bitumen and makes the covering brittle, while daily heating and cooling cycles work those brittle areas into splits. Winter rain and freeze-thaw then push water into cracks that were already there, which is why leaks so often appear months after the damage was actually done.
Is overlaying cheaper than replacing an asphalt roof?
Typically yes, and often by a substantial margin. Overlaying removes the cost of breaking out and disposing of heavy asphalt, removes skip and access costs associated with that removal, and shortens the programme so there is far less time during which the building is exposed. Most of our asphalt overlays come in well below a comparable strip-and-replace quotation.
Will the overlay work around rooflights, pipes and upstands?
Yes, and these details are where a liquid system has its biggest advantage over sheet materials. The resin and reinforcement are applied wet around any shape, so pipes, corners, kerbs, outlets and upstands are wrapped in the same continuous membrane as the main roof field, with no separate flashings or bonded cuts to fail later.
How much disruption is there for people inside the building?
Very little. The system is cold applied, so there is no flame, no gas and no hot works permit required. There is no breaking out, so no heavy demolition noise or dust. On occupied offices, schools and residential blocks we can normally work above people going about their day, with the roof rainproof again in as little as thirty minutes after application.
Services tailored to your flat roof, we work on any job.
From new installations and full system refurbishments to targeted leak diagnostics and repairs, every project is carried out by our in-house specialists using premium, manufacturer-approved liquid waterproofing systems.
Ready to get started?
Get an instant estimate for your flat roofing project today. No obligation, no hassle.