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Ubiflex Lead Substitute

Ubiflex Lead Free Flashing System

Lead Free Flashing is the modern day alternative to lead. It is used in areas where traditional Lead Flasing is used such as chineys, around rooflights and pitched valley linings.

Ubiflex is a non lead flashing material which can be used in all applications where lead is traditionally installed. Ubiflex can also be used to form damp proof courses and cavity trays in masonary walls.

Effective, attractive roof detailing - without the compromises

Use Ubiflex wherever you used to use lead

Ubiflex is malleable like lead, allowing it to be formed into an infanite variety of shapes,to form:

Stepped flashings

Abutment flashings

Chimney flashings

Pitched roof valley liners

DPCs and cavity trays in masonry walls

Rooflight and solar panel flashings

No scrap value means no risk of theft

Spiraling costs of metal has led to a huge increase in thefts of lead from buildings. This has in turn caused increased insurance premiums as well as huge inconvenience during remedial works. One of the many advantages of Ubiflex Lead Free Flashing is that it is only of value to the installer, it has no re-sale value as scrap. A sign installed:

 helps deter metal theft.

Saves time and money

Ubiflex Lead Alternative is up to 50% quicker to install than traditional lead, reducing time on site and the associated costs.

Important health and safety advantages

Ubiflex eliminates potential health risks assosiated with working in close contact with lead. It is also 80% lighter than lead, giving health and safety advantages as well as reducing structural loads.

A sustainable solution

Ubiflex Lead Free Flashing is environmentally friendly, non-toxic and recyclable.

BBA Certified

Ubiflex Lead Alternative carries BBA certification and is approved by NHBC and Zurich Insurance. Ubiflex is the only flexible Non Lead Flashing on the market with a BBA certificate for general use and a recent BRE wind tunnel test with Ubiflex B3 surrounding a chimney and sealed with Ubiflex Gap Seal, demonstrated that the flashing will resist wind speeds of up to 110mph (49m/s) without failing.

The Ubiflex System - setting new standards in flashings

The Ubiflex Lead Alternative is:

Up to 50% quicker to install than lead, is fully malleable, can be worked in both directions and is self-sealing if punctured.

Non susceptible to thermal movement. Aprons up to 12m long can be formed without seams or expansion joints - 8 x longer than traditional lead sheet! Consequently, there is less wastage with Ubiflex lead free flashings.

Compatible with all modern building materials and components, such as thermal panels, extract flues, ventilators, rooflights and flat roofing membranes including PVC single ply.

Stable and does not cause unsightly staining

Worked the same way as lead flashing but without the need for protective measures, and can be cut with a sharp knife or snips.

Performance of Ubiflex Lead Free Flashing


Modified polythin compound with an aluminium mesh reinforcement.

Temperature resistance:

-30 degrees C to +90 degrees C

Minimum working temperature:

By hand -10 degrees C

With hammer +5 degrees C

Use warmed material for improved malleability at low temperatures.


The ubiflex lead alternative is resistant to corrosion

Wind stability:

BRE wind tunnel tested to 110 mph

Life expectancy:

30 years

Tested to methods of artificial ageing by long term exposure to UV (A & B) radiation, elevated temperature and water. Individually and in combinations of two and all three elements.


25 years

Surface treatment:

The textured surface of Ubiflex Lead Free Flashing reduces staining.

Ubiflex Lead Free Flashing Roll Widths and Lengths

200mm x 12m (3.5mm) Lead Free Flashing Roll 9.6kg
300mm x 12m (3.5mm) Lead Free Flashing Roll 14.4kg
400mm x 12m (3.5mm) Lead Free Flashing Roll 19.2kg
500mm x 6m (3.5mm) Lead Free Flashing Roll 12.0kg

Ubiflex Lead Free Flashing Design guidance


When designed and installed in accordance with the relevant parts of BS 5534:2003, BS 6229:2003 and BS8000-6:1990, Ubiflex is suitable for use in flashing applications, such as abutments, chimneys, saddles, valleys and dormers to provide a weatherproof junction.
Unlike lead, Ubiflex can be used for long runs of up to 12m when used as a DPC or a cavity tray in masonry walls. In addition, Ubiflex is resistant to the corrosion which affects lead when portland cement containing free lime comes in contact with moisture so there is no need for additional paint protection. Ubiflex has excellent resistance to sliding under lateral loading and can withstand usual building settlement.

Cutting and folding can be carried out to a minimum temperature of 10°C and when working with a lead dresser to a minimum temperature of 5°C.

Foot traffic should be avoided or a protection board should be used when installing the product as a valley lining.

For instances where a lead wedge would normally be used, Ubbink have created a quick to install ‘V’ shaped fixing clip. Theses clips should be pushed into mortar joints at spacings of 450mm or less.

Overlap joints of 150mm are required in all flashings and must be sealed with Ubiflex High-Tack. Ubiflex flashings should be sealed to tiles, slates, glazing, upstands and soakers using a spot or continuous bead of High-Tack.

The Ubiflex System includes:

1. Ubiflex non-lead flashing

2. Ubbink High-Tack sealant: for sealing down to tiles, slates & overlap joints

3. Ubiflex Gap-Seal sealant: for sealing mortar joints

4. Ubiflex fixing clips: for easier fixing in mortar joints

5. Ubiflex ‘no lead’ sign: to reduce theft from site

Fixing Ubiflex into a wall or chimney

Without a DPC

On upstands, parapets, chimneys and walls without a damp proof course (DPC), Ubiflex should be turned into a joint or chase by not less than 30mm. Ubiflex should then be held in place with Ubiflex fixing clips, spaced not more than 450mm apart and then the joint filled with Ubiflex Gap-Seal (figure 01).

 figure 01

Ubiflex Gap-Seal has been designed to resist the cracking associated with mortar and protect the joints from water penetration.

With a DPC

When installing Ubiflex in a joint which includes a prefitted DPC, the mortar should be removed to a depth of not less than 30mm below the DPC, Ubiflex fitted and the joint sealed with Ubiflex Gap-Seal (figure 02).

 figure 02

If the DPC and Ubiflex are installed at the same time, the Ubiflex should be fitted to a depth of not less than 50mm with the edge turned back into a single welt to anchor it into the mortar (figure 03).

 figure 03

This method is particularly recommended when the height of masonry above the DPC is less than 600mm as there is a risk of the masonry lifting when clipping Ubiflex.

Larger Joints

Ubiflex can also be used in situations where the joint width is large or uneven, for example, in masonry in old or historic buildings. In these instances Ubiflex should be turned up the back of the chase and mechanically fixed with the joint filled with Ubiflex Gap-Seal.

Unlike lead, there is no need for a masking tape liner over Ubiflex when using mortar to fill shallow and wide joints.

Flashing to a flat roof upstand

Ubiflex should cover the upstand by at least 75mm and be sealed to it with a continuous bead of High-Tack sealant. (figure 04).

figure 04                                                                   The height of the upstand should be at least 150mm.

Flashing to a side abutment - double lap tiles/slates

Where double lap tiles or slates abut a wall they should be covered with Ubiflex stepped cover flashing (figure 05).

figure 05

The Ubiflex stepped flashing should be 150mm wide, cover the soakers by not less than 65mm and be sealed with a continuous bead of Ubiflex High-Tack.

Flashing to a wall or chimney: side abutment - single lap tiles

For single lap tiles a continuous Ubiflex cover flashing can be used (figure 06).


figure 06

This flashing should go up the wall 150mm (as double lap) and cover the tiles by at least 150mm (200mm for deep profiles or pitches below 25° in exposed areas) and be sealed with a continuous bead of Ubiflex High-Tack.

Alternatively, single lap tiles can be weatherproofed at abutments by using a cover flashing and a separate stepped flashing (figure 07). As in double lapped tiles, the cover flashing should run 75mm up the wall and the stepped flashing should be 150mm wide and overlap the cover flashing by 65mm.


figure 07

The stepped flashing should be sealed to the cover flashing with a continuous bead of Ubiflex High-Tack.

Flashing to a wall or chimney: top abutment - over tiles

When flashing a lean-to-roof or chimney in a pitched roof the Ubiflex should be turned up no less than 75mm and extend down the slope at least 150mm (200mm for pitches below 25° or exposed areas) and sealed to the roof covering (see figure 08).


figure 08

At the junction of chimney and ridge, a separate saddle flashing is required. This flashing should extend down both sides of the roof by no less than 150mm and along the ridge by no less than 150mm. The flashing edge which is beneath the ridge tile should be turned back to form a welted weather check (see also figure 10).

Flashing to a wall or chimney: top abutment - patent glazing

Ubiflex is ideal for flashing over patent glazing providing the glazing bars are not too deeply profiled (figure 09).

figure 09

Ubiflex should be turned up no less than 75mm and extend down the slope at least 150mm (200mm for pitches below 25° or exposed areas) and sealed to the glazing with Ubiflex High-Tack.

Photograph taken at BRE immediately after 49m/s (110mph) wind tunnel test.

Flashing to vertical tile and slate hanging

Ubiflex should be taken behind tiles by not less than 75mm and finished with a single weathercheck welt (figure 10).


figure 10

In slate hanging the Ubiflex extends 100mm behind the slates without the welt. Alternatively, soakers and a cover flashing can also be used in this instance and should follow the same procedure as shown in figure 05.

At the junction of the tiles/wall/cill, a separate cill flashing is required. This cill flashing extends up the wall at least 75mm and is chased into the brickwork minimum one course above the tiles or slates flashing (figure 11).

figure 11

Where the window opening appears within the body of the tile hanging, a similar cill flashing is required. This cill flashing turns under the cill and extends past the vertical edge of the window by at least 100mm and up the jamb by at least 100mm from the underside of the cill.

Pitched valley lining

Ubiflex is suitable for use in a valley gutter with all types of roof covering and boarded, battened and counterbattened roofs (Figure 12).


figure 12

Ubiflex sits directly on the valley boards - these should extend at least 225mm each side of the centre of the valley and include filting fillets positioned 150mm each side of the centre.

When the tiles/slates are laid the gap between then should not be less than 125mm. Valley boards (not less than 19mm thick) are laid on top of the rafters in boarded and counterbattened roofs or fixed flush with the top of the rafters in battened roofs - either notched into the rafters or fixed to noggins (trussed rafters).

Ubiflex extends across valley boards, over the fillets (the tops of which should be level with the top of the tiling battens) and is then fixed to the boards behind the fillet.

Ubiflex is then welted to protect the fixings and provide a weathercheck.

Cut edges of single lap tiles should be bedded on the Ubiflex with a clear water channel left behind the mortar bedding and the tilting fillet; double lapped tiles/slates are laid dry. Foot traffic should be avoided or a protection board should be used during installation.

Flashing to rooflights, northlights and solar panels

Most new, modern skylights and solar panels are supplied with built-in flashings. However, where this is not the case or flashings to existing skylights and solar panels need to be replaced, then Ubiflex should be formed up and over the upstand and extend 150 - 200mm into the roof covering.

Flashings should be positioned beneath plain tiles and slates (top and sides) and over profiled tiles. Northlights are flashed by dressing the Ubiflex over the ridge and shaping over the glazing bars as in figure 09. Ubiflex should extend 150 - 200mm down each side of the slope and be sealed to the glazing with a continuous bead of Ubiflex High-Tack.

Flashing to canopies, hoods and carports

Ubiflex can be used as a flashing to modern fibreglass, GRP and plastic door/window/patio canopies, door hoods and carports. For canopies and hoods with upstands follow the procedure as shown in figure 13, ensuring the flashing is sealed to the canopy etc. and covers the upstand by at least 75mm and extends at least 100mm beyond the sides.

figure 13

For canopies and carports without upstands the procedure is similar to the top abutment flashing shown in figure 08 (see page 08) ensuring that the flashing is sealed to the canopy or carport and extends and at least 150mm over the canopy and 100mm beyond the sides.

Supply, handling and storage

Ubiflex rolls are supplied packed individually in boxes and should be stored in a dry area. No special handling is required during storage or installation. Ubiflex is non-toxic and recyclable.


Ubiflex can be worked in the same way as lead, but without the need for any protective measures.

Ubiflex can also be used in direct contact with any building material, including copper, zinc, iron, aluminium and stainless steel, in most climate conditions and environments.

Ubiflex Lead Free Flashing can be:

Cut with a sharp knife

Fixed with stainless steel nails if required

Joined with Ubiflex High-Tack sealant to form a watertight joint

Maintenance and repair

Ubiflex is self-sealing if punctured.

Ubiflex does not require any maintenance in addition to a regular visual check for damage.