C Stevens Roofing

Polyester Flat Roofing

The most common system used by C. Stevens Roofing is polyester combining value, flexibility and a 12 year guarantee. NORDGUM is one of the most convenient solution for roofing and renovation works and waterproofing details. Good values of mechanical resistance thanks to the non woven polyester carrier and excellent low temperature flexibility permit to use it in difficult climate conditions at economic rates.

Waterproofing membrane made of Polymer elastomer modified bitumen (SBS) and reinforced with a non woven polyester carrier. The compound is a mixture of distilled bitumen and thermoplastic rubber which is Styrene Butadiene Styrene (SBS). The bottom surface is covered by a poliethilene burn off film.

Two finishes are available:

• NORDGUM (plain) available in 3mm, 4mm and 5 mm thickness or 4 Kg/m2 and with upper surface covered with sand or poliethilene burn off film on request.
• NORDGUM MINERAL available in 4 Kg/m2 and 4,5 Kg/m2, with upper surface covered by natural slate granules in order to protect the membrane against U.V. radiations.

Uses and Application

NORDGUM is one of the most convenient solutions for roofing renovation work and general waterproofing. Nordgum achieves good values of mechanical resistance thanks to the non woven polyester carrier and excellent low temperature flexibility that permit it to be used in difficult climatatic conditions.

The high degree of elasticity and flexibility allow the use in conjunction with elastomeric and polymer plastomer modified membranes which are reinforced with non woven polyester fabric, and the use as complementary layer in a two layer waterpoofing system.

Membranes are particularly well suited for the waterproofing of structures which may be subjected to limited movement or dimensional changes such as: -

• Flat, sloping and pitched roofs
• Site cast reinforced concrete
• prefabricated concrete
• Masonry cement
• Metal and laminated wood deck terraces
• Foundations
• Antiseismic foundations
• Car parks
• Tunnels

Applications instructions: The application of the membrane is by torch bonding using a suitable propane gas torch. Other tools include a knife and a trowel with a rounded end. Depending on the structure and the specification the membrane may be partial or spot bonded, loose laid or fully bonded.

When deciding on the system to use refer to our Specifier's Guide leaflets. The membrane should be applied to the substrate using a propane gas torch; this is used to burn off the burn-off film and melt a thin layer of bitumen while unrolling and laying the membrane. For a "spot bonding" installation, apply the flame only to those areas of the sheet to be bonded to the substrate making sure that the bonded areas are evenly distributed.

All membranes must be laid to allow side laps of 80 mm and end laps of 150 mm. If the membrane is only partially bonded remembel; that'll bonding must always take place for 1 meter each side of the end laps. Finally, SBS modified bitumen membranes can be used as exposed cap sheets only if the membrane ifr self- protected by mineral slate granules.

GRP Flat Roofing

GRP is a specifically modified high performance waterproofing system, designed to a provide a permanent solution to the problems usually associated with bitumen based coatings. For example cracking and blistering of the surface caused by the effects of sunlight which can result in failure of the roof within a few years.

GRP more commonly referred to as "glass fibre" is formed in situ by reinforcing polyester resin, which has been cured or hardened using a peroxide based catalyst with an emulsion bound chop strand mat. Once cured this forms a joint free laminate that will outlast virtually any other traditional roofing material..

Glass Reinforced Plastic

GRP is a specifically modified high performance waterproofing system, designed to a provide a permanent solution to the problems usually associated with bitumen based coatings. For example cracking and blistering of the surface caused by the effects of sunlight which can result in failure of the roof within a few years.

GRP more commonly referred to as "glassfibre" is formed in situ by reinforcing polyester resin, which has been cured or hardened using a peroxide based catalyst with an emulsion bound chop strand mat. Once cured this forms a joint free laminate that will outlast virtually any other traditional roofing material.

GRP Advantages

Glass Reinforced Plastic roofing has many advantages :

• 20 Year Guarantee
• Cold Applied and Cured
• Maintenance Free
• BAA Acredited
• Fire Retardent
• Lightweight

GRP roofing is a cold applied system that is ideally suited to both simple and complex structural designs and can be rapidly applied and cured to prevent water ingress giving total protection. The weld free design gives a continuous high performance covering. Available in a range of colours to suit the project, ideal for balconies, walkways, gutters and valleys and any domestic roof. The finish can simulate lead or other traditional finishes.

High performance is achieved as the GRP is made up of a combination of modified polyester base resins, emulsion bound chop strand mat and a finishing coat of pre-pigmented topcoat. When cured GRP is guaranteed to provide performance beyond that of more traditional bitumen or polymer based waterproofing coatings.

GRP Applications

GRP systems have been used successfully for over 20 years. They are fast becoming the preferred choice of Architects, Specifiers and Local Authorities. Installed by highly skilled and suitably trained installers, clients can be assured that GRP will continue to perform long after more traditional coatings have failed.

Every waterproofing application is formed entirely using GRP (Glass reinforced Polyester) guaranteeing no variation in rates of thermal expansion within the laminate. Being cold applied it can be easily installed to any shape or form and to close even the most complicated detail.

Thousands of square metres of specifically modified GRP waterproofing coatings are chosen every year with confidence, by discerning customers. A system complete with a comprehensive guarantee, which can be insurance backed if required. A system that has undergone extensive testing and is only installed by trained professionals.

The flexibility of GRP allows unusual shapes to be covered with ease and the GRP system can successfully be adapted for application to pitched roofs and vertical walls. The smooth tough surface can with-stand light foot traffic and may be upgraded at the time of application for use on balconies.