Alumasc Roofing

Hydrotech Monolithic Membrane 6125 roof waterproofing system

Manufacturer: Alumasc Roofing 

Materials: Hot Applied Polymer Modified Bitumen (Hot Melt) 

The Hydrotech Monolithic Membrane 6125 Roof Waterproofing System comprises of:

• Alumasc Bitumen Primer — a cold, spray-applied bituminous primer for use on horizontal, vertical and sloping surfaces. The coating can also be applied by brush or roller at a rate of from 8 m2 per litre to 16 m2 per litre
• SB Primer — alternative fast curing primer
• Hydrotech Monolithic Membrane 6125 — a hot-applied, polymer-modified, rubberised bitumen-based membrane, including 30% recycled material content. The system is applied in two layers to provide a coating with a nominal thickness of 6 mm
• Flex Flash F — a spunbond polyester fabric reinforcement sheet
• Flex Flash UN — an uncured neoprene rubber reinforcement sheet
• Hydrogard 10 — a lightweight oxidised-bitumen glassfibre-reinforced protection sheet
• Hydrogard 20 — a polyester-reinforced modified-bitumen protection sheet
• Hydrogard 20 AR — a root-resistant polyester-reinforced modified-bitumen protection sheet, incorporating root repellent
• Hydrogard 30 — a heavy-duty dual-reinforced modified-bitumen protection sheet
• Hydrogard 40-AR — a root-resistant polyester-reinforced modified-bitumen protection sheet, incorporating root repellent
• Hydrogard 50 — a dual glass/polyester-reinforced, APP-modified bitumen heavy-duty protection sheet
• Alumasc Extruded Polystyrene — an extruded polystyrene (XPS) foam board, available in two standard sizes and rebated for lap jointing for use in inverted roof specifications
• Alumasc Separator Sheet — a water flow-reducing layer for use above thermal insulation in inverted roof specifications.

BBA logo

Number: 90/2431 PS1
Issue date: 29/08/2018

ETA logo

Number: 20/0907
Issue date: 01/12/2020

Approved for use on

Flat Roofs Green Roofs Podium Decks Roof Gardens Zero Falls Buried Roofs 

The Hydrotech Monolithic Membrane 6125 Roof Waterproofing System is satisfactory for use as a protected waterproofing layer on zero fall roofs, flat roofs and podiums with limited access in:
• inverted roof specifications
• protected roof specifications, eg covered by pavers or other suitable protection, or
• green roof and roof garden specifications.


Concrete Timber 

The system is suitable for use on in-situ concrete, precast concrete, concrete block and timber substrates. The substrates must comply with the relevant requirements of BS 6229 : 2003 and, where appropriate, NHBC Standards 2018, Chapter 7.1.


Design Life of the Roof 

The waterproofing component will provide an effective barrier to the transmission of moisture for the service life of the roof in which it is incorporated.

The insulation board is rot resistant and, as long as the water flow-reducing layer remains undamaged, will have a life of at least 25 years under normal circumstances.

Under normal service conditions, the water flow-reducing layer will have a service life equivalent to that of the insulation in the inverted roof.

Care must be taken to ensure that the protection/ballast layer provides complete cover to the water flowreducing layer during the membrane service life to avoid UV degradation.

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

An estimate cannot be given for the life of green roof and roof garden specifications owing to the nature of use. However, under normal circumstances, it should be significantly greater than for open coverings.

The waterproofing membrane component is resistant to acidic and alkali conditions it is likely to encounter during its service life, as well as chemicals, such as liquid fertiliser, it may come into contact with.

Installation Requirements

The system should only be installed by contractors who have been trained and approved by the Certificate holder, from whom details can be obtained.

Fire Safety

The system, when used in protected specifications, including an inorganic covering listed in the Annex of Commission Decision 2000/553/EC, can be considered to be unrestricted under the national Building Regulations.

The designation of other specifications should be confirmed by: England and Wales — test or assessment in accordance with Approved Document B (Volumes 1 and 2), Appendix A, clause A1, Scotland — test to conform to Mandatory Standard 2.8, clause 2.8.1 Northern Ireland — test or assessment by a UKAS-accredited laboratory, or an independent consultant with appropriate experience.

In the opinion of the BBA, irrigated green roofs and roof gardens will also be unrestricted under the national Building Regulations.

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

Certified Products

The following products are also covered by the same certification:

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Alumasc Roofing

White House Works
Bold Road
St Helens

T : 01744 648 400

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