Grey liquid roofing for all roof types.

Allcoat UltraFlex


20Ltr – £165.00

Allcoat UltraFlex is a single component liquid applied coating based on polyurethane technology, which cures by reacting with atmospheric moisture to give a seamless and waterproof polymer film that is rubbery and elastic.

Allcoat UltraFlex, by virtue of its chemical reactivity in the wet state, has good adhesion to a wide range of substrates. Unlike more traditional bitumen based products, Allcoat UltraFlex does not readily embrittle with age, exposure to ultra violet radiation or weathering, hence it does not crack or craze.

Allcoat UltraFlex is not adversely affected by extremes of temperature – consequently it does not crack at low temperatures or suffer thermal flow at elevated temperatures.

Allcoat UltraFlex is a very high solid coating designed to give a high-build film. It can be brush or roller applied but it has a higher viscosity than a conventional paint and should not be diluted.

Allcoat UltraFlex can be supplied as a sprayable grade, suitable for airless spray equipment. Please refer to Allcoat’s Technical Department for the correct procedure.

Allcoat UltraFlex is designed to bond to many types of substrate, either directly or in conjunction with a suitable primer, particularly those commonly used in roofing, such as felt, asphalt, slate, tiles, asbestos, concrete, brick, wood, glass and metals. In addition, Allcoat UltraFlex can also be applied directly to spray applied polyurethane (PU) foam insulation such as Metflex SupaFlex 5

Areas of Application:

The elastomeric membranes are designed to bond to many types of substrate particularly those commonly used as roofing, such as felt, asphalt, slate, tiles, asbestos, concrete, brick, wood, glass and metals. They can also be applied to spray polyurethane (PU) foam insulation. However, it is essential that the substrate and structures are properly prepared and stable.

Surfaces previously treated with silicone based materials will inevitably be difficult to overcoat and this should not be attempted with ALLCOAT products. Substrates with poor adhesion to the underlying structure (e.g. blistered roofing felt) may also cause problems in providing sound over coating.

Preferential vapour drive in buildings must also be borne in mind when overcoating a roof and it may be judged expedient to employ ventilation to cope with transmission of high levels of moisture vapour.

Methods of Application:

The dry film thickness (DFT) of ALLCOAT UltraFlex should not be less than 0.5mm or more than 1.0mm for each coat. Rough or textured surfaces will reduce the coverage rate and consequently more material must be allowed to achieve the minimum DFT.

ALLCOAT UltraFlex is a membrane coating, not a paint and as such protection is only achieved with a high film build, i.e. 1mm on flat surfaces minimum. It is therefore essential that this is achieved. The membrane can be applied in one 1mm or two 0.5mm coats. Two coats are recommended on uneven and jointed surfaces to minimise the possibility of thin patches, missed areas and pinholing. In the case of two-coat application, it is important to re-coat within 24 hours of the first coat becoming sufficiently cured to allow operator access.

Coverage rates may vary with surface texture and porosity. The information given is based on average usage. A site trial is recommended.

ALLCOAT PU Primer: 6 – 10m²/lt

ALLCOAT UltraFlex: 1 litre/m² on a smooth flat surface will provide an adequate film thickness of approximlately 1mm.

Any surface texture will increase the surface area which must be allowed for when calculating usage e.g. on a chipping embedded surface the actual area will be approximately doubled.

To minimise drips and runs, Allcoat UltraFlex should be applied to sloping or vertical surfaces in thin coats of approximately 0.3L/m2

Total coverage 0.9lt / m² in 3 coats to give D.F.T approx. 800 microns. A Thixotropic additive can be mixed with Allcoat UltraFlex on-site to allow increased film thickness to be achieved, reducing the number of required coats.

Application – Typical Flat Roof

Do not dilute Allcoat UltraFlex!

  1. Remove all loose material by vigorous brushing, wire brush if necessary.
  2. Treat any fungal growth with proprietary fungicide as recommended.
  3. It may be necessary to jetwash or abrasive-blast the roof structure to remove heavy or well-rooted deposits of organic material. If the substrate to be prepared is old asbestos, please refer to the guidance from the HSE regarding proper working practices with asbestos cleaning and handling.
  4. Any chemicals used in the preparation process, must be washed away thoroughly with water.
  5. Allow surface to dry thoroughly and any moisture contained in the structure to evaporate. Allcoat PU Primer and Allcoat UltraFlex should not be applied to damp substrates. Recommended moisture content; <5%.
  6. Fill cracks and voids with a polyurethane mastic sealant. Large cracks and gaps may require filling with backing rods first. Refer to the specific guidance of the sealant used.
  7. Apply a bead of Allcoat PU Mastic to all square edges such as between the roof surface and parapet walls, corners and around the edges of upstands.
  8. Prime entire surface with Allcoat PU Primer (6 – 10 m² / It depending on substrate texture and porosity) which cures to a slightly tacky film within 2-4 hours.
  9. Apply Allcoat UltraFlex (0.5L/m2) by roller 150mm either side of all upstands, corners, edges, seams/joints, filled-in cracks and other repairs and while the Allcoat UltraFlex is still wet, apply suitable width reinforcing scrim tape to these areas (minimum 150mm wide or at least 50mm wider than the detail being covered).
  10. Immediately apply a second coat of Allcoat UltraFlex on top of the reinforcing scrim and to the extent of the first coat of Allcoat UltraFlex. Allow the roller to push out any air bubble s trapped in the reinforcing scrim
  11. The following day, Overcoat all areas with Allcoat UltraFlex, or within 48 hours of the initial primer application. If delays cause the overcoat window to be exceeded, re-priming is advised.
  12. Apply Allcoat UltraFlex at a maximum film thickness of 1 mm for a single coat
  13. The first coat should be touch dry in as little as 6 hours but more typically within 12 – 24 hours (in some weather conditions this might be delayed, such as low temperature or low humidity).
  14. Second coat delay: – if more than 24 hours elapse after touch dry stage of the first coat, prime the entire surface with Allcoat PU Primer and allow to dry before recoating within 4 – 8 hours.
  15. Day-work joints – where application extends over more than a working day, an overlap of 150mm should be used. Strategic priming and detail work should also be considered if the project is going to run for several days.
  16. Aromatic hydrocarbon solvent should be used to clean equipment etc.

ALLCOAT UltraFlex Spray Grade: Application

Only airless spray should be used 63 : 1 Graco King
Compressor: 100psi, 60cfm minimum
Tip Size: 21 – 25 thou 50° angle
100’ x 3/8 House and 25’ Whip End

Spray Application Rate:

ALLCOAT UltraFlex is easily and quickly applied manually at a rate of 100m² per man or up to 600m² per day by spray application.

It is recommended to incorporate a gridding system to assist in the accurate metering of coverage.



20 litres


Dark Grey


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