Ubbink Ubiflex is a lead free flashing material made from aluminium mesh coated on both sides with modified bitumen. It is used in virtually every application where traditional lead flashing would normally be installed - chimneys, abutments, valleys, dormers and solar panels - but it is up to 80% lighter, up to 50% faster to fit, and has zero scrap value, which removes the risk of lead theft altogether.
If you're a homeowner planning a re-roof or extension, or a roofer weighing up lead alternatives, this guide covers exactly what Ubbink Ubiflex is, how it performs against traditional lead, and where it can (and can't) be used.
What Is Ubbink Ubiflex?
Ubiflex is a non-lead waterproof flashing manufactured by Ubbink, a Dutch building products specialist with a long-established presence in the UK roofing market. The product is constructed by coating both sides of an aluminium mesh reinforcement with a mixture of modified bitumen and additives. The underside is finished with a kraft paper and film backing, while coloured granules are applied to the top surface - the lead-grey finish looks remarkably close to traditional lead once dressed onto a roof.
The Ubiflex range includes three main products:
- Ubiflex Standard (B3) - the core 3.5mm lead replacement flashing, typically used for facade intersections, chimneys, abutments and longer runs.
- Ubiflex Finio -a self-adhesive version with integrated butyl strips, developed specifically for fast, reliable roof intersections. It can be dressed at temperatures as low as 5°C and sticks to most building materials.
- Ubiflex Extreme - the premium variant with a textured silicone coating on both sides (one grey, one black), so it can be installed with either face showing.
Key Features and Specifications
Ubiflex Standard B3 - the most widely specified product in the range -carries the following credentials:
- Thickness: 3.5mm nominal
- Widths: 150mm, 200mm, 250mm, 300mm, 450mm, 500mm and 1000mm
- Lengths: 6m and 12m rolls
- Colours: Grey, Black and Terracotta
- Life expectancy: 30 years
- Guarantee: 25 years
- Temperature resistance: -30°C to +120°C
- Minimum installation temperature: 5°C
Certifications That Set Ubiflex Apart
Ubiflex B3 is the only flexible lead free flashing on the UK market with a BBA (British Board of Agrément) certificate for general use. It is also approved by the NHBC, which matters enormously if you're building under an NHBC warranty - many lead alternatives are not accepted.
Independent BRE wind tunnel testing of Ubiflex B3 fitted around a chimney and sealed with Ubiflex Gap Seal demonstrated resistance to wind speeds of up to 110mph (49m/s) without failure. The product also carries fire classifications of Class E to EN 13501-1 and Class B to BS 476-3:2004.
The Advantages of Ubbink Ubiflex Over Traditional Lead
1. Up to 80% Lighter Than Lead
A roll of Ubiflex weighs a fraction of the equivalent lead sheet. That means easier manual handling on site, safer working at height, simpler transport and less load on the roof structure itself.
2. Up to 50% Faster to Install
Ubiflex cuts with a knife or scissors, dresses easily with a standard lead dresser, and bonds with High Tack adhesive rather than requiring traditional leadwork skills. On detailed work -stepped flashings, awkward junctions, penetrations -the time saving is significant, and that translates directly into lower labour costs.
3. Zero Scrap Value: The End of Lead Theft
Lead theft remains a genuine and costly problem across the UK, with stolen lead flashing leaving roofs exposed and causing water damage that can run into tens of thousands of pounds. Ubiflex was developed partly in response to this. Because it contains no lead, it has no resale value as scrap -thieves simply leave it alone. For churches, schools, commercial premises and homes in theft-prone areas, this single advantage often justifies the switch.
4. No Thermal Movement Problems
Traditional lead expands and contracts with temperature changes, which limits individual lead pieces to roughly 1.5m before expansion joints are required. Ubiflex is unaffected by thermal movement, so continuous runs of up to 12m can be formed without seams or expansion joints -up to 8 times longer than lead sheet. Fewer joints means fewer potential failure points and less material wastage.
5. Safer and Non-Toxic
Lead is a toxic heavy metal, and repeated handling carries genuine health considerations for installers. Ubiflex is non-toxic, improving health and safety on site, and the material is recyclable -making it the more environmentally responsible choice.
6. Self-Sealing and Corrosion-Resistant
Ubiflex is self-sealing if punctured and can be worked and reworked in both directions without affecting performance. Unlike lead, it isn't attacked by the free lime in Portland cement, so there's no need for patination oil or additional paint protection where it meets fresh mortar.
7. Stable, Predictable Pricing
Lead is a traded commodity, and its price moves with global markets -which makes quoting jobs in advance harder. Ubiflex pricing is stable, so contractors can quote with confidence.
Where Can Ubiflex Be Used?
Ubbink Ubiflex performs in virtually all applications where lead flashing is traditionally specified:
- Chimney flashings
- Stepped and abutment flashings
- Pitched roof valley liners
- Cover flashings and aprons
- Dormer window flashings
- Rooflight and conservatory flashings
- Solar panel flashings (a fast-growing application)
- Damp proof courses (DPCs) and cavity trays in masonry walls
Its malleability makes it particularly effective on detailed or awkward junctions, where cutting and sticking Ubiflex is far quicker than working lead.
How Is Ubiflex Installed?
Installation is straightforward, which is a large part of its appeal:
- Cut the Ubiflex to size with a knife or scissors.
- Shape and dress it into the junction using a standard lead dresser, following the profile of the tiles or slates.
- Bond the flashing by lifting the front edge and applying a bead of Ubbink High Tack adhesive, then pressing the Ubiflex firmly down to create a waterproof, windproof seal.
- Seal the mortar joints with Ubbink Gap Seal to complete the installation.
Cutting and folding can be carried out down to 10°C, and dressing with a lead dresser down to 5°C - so it remains workable through most of the UK roofing season.
Is Ubbink Ubiflex Right for Your Project?
For new builds, extensions, re-roofs, solar installations and any property in a theft-prone location, Ubiflex is a proven, certified and cost-effective lead free flashing solution. The one notable exception is heritage work: on listed buildings and in conservation areas, traditional lead may still be required by planning conditions, and for ultimate longevity in heritage settings lead remains unsurpassed.
For everything else, the case is compelling - and the 25-year guarantee, BBA certification and NHBC approval mean you're not trading peace of mind for convenience.
Frequently Asked Questions
How long does Ubbink Ubiflex last? Ubiflex has a life expectancy of 30 years and is supplied with a 25-year guarantee.
Is Ubiflex as good as lead? For the vast majority of flashing applications, yes — and it's lighter, faster to fit, theft-proof and non-toxic. Traditional lead still holds the edge for heritage and conservation work where longevity beyond 100 years is required.
Can Ubiflex be used on solar panel installations? Yes. Solar flashing is one of Ubiflex's key applications, and its light weight and flexibility make it well suited to in-roof solar systems.
Does Ubiflex meet UK building standards? Yes. Ubiflex B3 is BBA certified for general use — the only flexible lead free flashing with this certification — and is approved by the NHBC.
What colours does Ubiflex come in? Grey, Black and Terracotta, allowing it to blend with slate, tile or clay roofs. The grey finish closely resembles traditional lead.
Considering lead free flashing for your next project? Purchase Ubbink Ubiflex lead free flashing here at All Flat Roofing Supplies.
