Proteus Waterproofing

Pro-BW Plus System

Manufacturer: Proteus Waterproofing 

Materials: Flexible Polyesters 

The Pro-BW Plus System is a liquid-applied, glass-reinforced, flexible modified polyester system, available in
unpigmented or pre-pigmented versions.

The Pro-BW Plus system consists of:
• Pro-BW Plus Resin — a flexible, modified polyester resin
• Pro-BW Pigment — a pigment dispersed in a polyester resin, available in in mid-grey as standard; other nonstandard colours are available on request
• Pro-BW Catalyst — 50% dibenzoyl peroxide powder
• Pro-Force 450 — a 450 g·m–2 glassfibre mat for reinforcing the system
• Pro-Aggregate EM — a surface finish to provide an anti-slip surface if required.


BBA logo

Number: 18/5574
Issue date: 10/10/2018

Approved for use on

Flat Roofs Green Roofs Inverted Roofs Pitched Roofs Zero Falls Buried Roofs 

For use as a liquid-applied roof waterproofing system on new or roofs with limited or pedestrian access in the following specifications:
• exposed warm and cold flat and pitched roofs(1)
• protected warm and cold flat and zero fall roofs (ie covered by pavers or other suitable protection)(1)(2)
• green (extensive) flat, zero fall and pitched roofs(1)(2)
• inverted flat and zero fall roofs(1)(2)

(1) Limited access
(2) Pedestrian access


Concrete Insulation Boards Mastic Asphalt Metal Plastic Reinforced Bituminous Membranes Single Ply Membranes - EPDM Single Ply Membranes - PVC Single Ply Membranes - TPO Timber 

The system is suitable for use on the following substrates:
• concrete
• asphalt
• plywood(1)
• OSB 3(2)
• reinforced bitumen membranes (including sanded and mineral-surfaced felts)
• insulation(1)
• single-ply membranes(2)
• previously-coated surfaces(2)
• small areas of metal incidental to the roof, eg pipe upstands
• small areas of plastic-coated metal incidental to the roof(1)

(1) Grades approved by the Certificate holder.
(2) The advice of the Certificate holder should be consulted on compatibility with the system


25 Years 

The system will achieve an initial life expectancy, for an exposed roof, of at least 25 years. When fully protected and subjected to normal service conditions in an inverted roof specification with an open covering (eg aggregate pavers), the system can provide an effective barrier to the transmission of liquid water and water vapour for the design life of the roof in which it is incorporated.

In situations where maintenance or repair of any of the components in the roof structure are necessary (eg the protection layer or insulation), the durability of the membrane may be reduced. In these circumstances the Certificate holder should be consulted.

An estimation cannot be given for the life of green roof specifications owing to the nature of use; however, under normal circumstances, it should be significantly greater than for exposed waterproof coverings.

Installation Requirements

Installation of the system must be carried out only by specialist roofing contractors trained and approved by the Certificate holder.

Fire Safety

When tested to DD CEN/TS 1187 : 2012, Test 4, the following flat roof systems achieved a classification under BS EN 13501-5 : 2016 of BROOF(t4):

  • a 6 mm calcium silicate board, one coat of Pro-BW Primer at 0.25 litres per m2 , one coat of Pro-BW Plus resin at 1.25 litres per m2, a layer of Pro-Force 450 reinforcement and one coat of Pro-BW Plus resin at 0.50 litres per m2.
  • a primed 19 mm orientated strand board, a self-adhesive vapour control layer, a 120 mm thick, foil faced polyisocyanurate insulation board bonded with a polyurethane adhesive, one coat of Pro-BW Plus resin at 1.25 litres per m2, a layer of Pro-Force 450 reinforcement and one coat of Pro-BW Plus resin at 0.50 litres per m2.

The membranes, when used in protected or inverted roof specifications, including an inorganic covering listed in the Annex of Commission Decision 2000/553/EC, can be considered to be unrestricted under the national Requirements.

The designation of other specifications, eg when used on combustible substrates, should be confirmed by: England and Wales — test or assessment in accordance with Approved Document B, Appendix A, clause 1. Scotland — test to conform to Mandatory Standard 2.8, clause 2.8.1(1)(2). Northern Ireland — test or assessment by a UKAS-accredited laboratory, or an independent consultant with appropriate experience.

In the opinion of the BBA, when used in irrigated roof gardens or green roofs, the use of the membrane will be unrestricted under the requirements of the national Building Regulations.

If allowed to dry, the plants used may allow flame-spread across the roof. This must be taken into account when selecting suitable plants for the roof, and appropriate planting, irrigation and/or protection should be applied to ensure that the overall fire-rating of the roof is not compromised.

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Proteus Waterproofing

21a Sirdar Road
Brook Road Industrial Estate

T : 01268 777871

E :

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