ALUMASC EXTERIOR BUILDING PRODUCTS LTD

Tel: +44 (0)1744 648400 Email: waterproofing@alumasc-exteriors.co.uk

Website: www.alumascwaterproofing.co.uk Ref: SD004FR Issued: 01/06/12 Page 1 of 2

DerbigumTwo Layer Torch-Applied Bituminous Inverted Roof

When to Specify Derbigum two layer, torch applied, high performance inverted roof systems offer the highest levels of durability, protection and waterproof integrity for new construction and are particularly suitable for roof terraces designed for pedestrian access.

Warranties Alumasc offers a comprehensive range of warranty options. The typical warranty period for Derbigum is 20 years. Installed exclusively by Derbigum Approved Contractors and underpinned by Alumasc’s extensive project support service, Alumasc warranties cover both product and installation. Independent insurance backed latent product defect warranties are also available through FSA licensed brokers.

Key FeaturesLifespanIn the Derbigum BBA Certificate 86/1593C, the BBA say ‘All available evidence suggests that the product will have a life in excess of 30 years.’

DurabilityDerbigum has a high softening point ensuring stability of the membrane in the hottest weather, high tensile strength and excellent puncture resistance. Derbigum can be installed without any surfacing, regardless of the method of application due to the unique blend of polymers which make Derbigum resistant to UV degradation.

PerformanceDerbigum is a range of dual-reinforced, APP (Atactic Polypropylene) modified bitumen, high performance roofing and waterproofing membranes with a life expectancy of 30-35 years according to independent assessment. Enhanced performance properties include low temperature flexibility, excellent fire ratings, stronger reinforcement and ease of application.

Cost-effectiveDerbigum Two Layer Inverted Systems combine proven durability with speed and ease of installation. The inverted insulation system offers additional protection against UV and mechanical damage and significantly extends the life of the roof.

QualityAlumasc operates a quality assurance management system which is independently audited to BS EN ISO 9001:2008. Alumasc extends this quality management to their network of approved installers, for single source accountability and peace of mind.

EnvironmentAlumasc actively pursues sustainability in the full range of products and systems the company offers through its accreditation to the ISO 14001:2004 Environmental Management Standard. Alumasc, its partners and its suppliers are committed to putting consideration for the built and wider environment at the core of all aspects of their current business and future development. Derbigum membranes are 100% recyclable.

Concrete Paviours/Stone Ballast

Alumasc Polyethylene Separator Sheet

Alumasc Extruded Polystyrene

Screed (primed)

Concrete Deck

CERTIFICATE No 86/1593

Euroroof Mastergold Underlay

Derbigum Black Cap Sheet

ALUMASC EXTERIOR BUILDING PRODUCTS LTD

Tel: +44 (0)1744 648400 Email: waterproofing@alumasc-exteriors.co.uk

Website: www.alumascwaterproofing.co.uk Ref: SD004FR Issued: 01/06/12 Page 2 of 2

DerbigumTwo Layer Torch-Applied Bituminous Inverted Roof

Application1. Prime the screeded concrete deck and upstands with Alumasc Bitumen

Primer and allow to fully dry.

2. Install Euroroof Mastergold Underlay, fully bonded by torch application, with 100mm side and 150mm end laps.

3. Install Derbigum Black Cap Sheet, fully bonded by torch application. Joints to be staggered with underlay.

4. Note: Pre-cut the lower corner of the end of each roll at 45º where it will be overlapped by the end lap of the next roll.

5. Seal side laps (100mm) end laps (150mm) with a shoe burner torch. All laps must be pressure rolled with a 15kg long handled roller. A small (approx 5-10mm) continuous bead of compound must always visible at the joint.

6. All detail work to be executed in two layers, the first layer being Hi-Ten Universal, followed by the cap sheet of Derbigum, both fully bonded by torching. At all upstands install a 100 x 100mm reinforcement strip of Derbigum Black into the angle. The main sheet area must overlap onto the reinforcing strip by the full 100mm. Install a final flashing piece of Derbigum Black or Mineral, fully bonded to the upstand and overlapping onto the main horizontal sheet area by a minimum of 100mm.

7. Install Alumasc Extruded Polystyrene insulation board, loose laid and tightly butted together, with staggered end laps. Thickness to be calculated to meet thermal requirements.

8. Overlay the insulation with Alumasc Polyethylene Separator Sheet, loose laid with 300mm overlaps in the direction of the underlying falls.

9. Install concrete paviours on Harmer Uni-Ring Paving Supports and/or 20-40mm round washed ballast.

10. For vertical details, fully bond the Euroroof Rapid membrane onto the detail underlay, ensuring a vertical upstand of at least 150 mm above the adjacent roof finish and overlap onto the horizontal surface by at least 100mm. Detail work to be in accordance with project specification.

NB: It must be established by a structural engineer that the structure is capable of bearing the weight of the inverted system plus associated live loads.

Derbigum waterproofing systems are exclusively installed by a nationwide network of Derbigum Approved Contractors.

The company pursues a policy of constant product development and information contained in this publication is therefore subject to change without notice. The customer is responsible for ensuring that each product is fit for its intended purpose and that the conditions for use are suitable. All quoted data is nominal and subject to production tolerances.

System Componentsn Concrete paviours and/or 20-40mm round

washed stone functions as ballast to resist wind uplift and flotation, and enable the roof area to be used as a terrace if required.

n Alumasc Polyethylene Separator minimises the cooling effect of rainwater on the underlying insulation by draining the water efficiently to the roof outlets, therefore reducing the thickness of insulant required.

n Alumasc Extruded Polystyrene is a zero ODP, 100% recyclable, CO2 blown insulation with a GWP of <5, supplied in 1250 x 600mm boards with rebated edges, in a range of thicknesses and compressive strengths.

n Derbigum Black Cap Sheet is a high performance, APP modified bituminous membrane, with dual glass/polyester reinforcement, applied by torch application.

n Euroroof Mastergold Underlay is a polyester based, APP modified bitumen base layer, suitable for torch application.

n Alumasc Bitumen Primer is a low viscosity, solvent-based bitumen primer intended to maximise the adhesion of bituminous membranes to metal and porous substrates.

Technical SupportAlumasc Technical Services provide an extensive project support service that includes site surveys, project specifications, performance calculations (e.g. U-values, condensation risk analysis), CAD detail drawings and general technical advice.

Contact Alumasc Technical Services via:

+44 (0) 1744 648400

waterproofing@alumasc-exteriors.co.uk

Online resources are available on our website or via the embedded links below:

Web Links

Brochures & Datasheets

NBS Specifications

CAD Drawings for typical details

www.alumascwaterproofing.co.uk