Following the publication of Guidance Note No. 7 by the Liquid Roofing and Waterproofing Association (LRWA), there appears to be significant uncertainty as to its content. Simon Poe, Business Operations Director with Alumasc Roofing, explains what implications the Guidance Note has for flat roofing specifications.

A common misconception is that the guidance prevents the use of liquid-applied waterproofing with zero falls. However, whilst the use of some products in certain zero falls applications are prohibited, specific provision is made (in both the Guidance Note and BS 6229:2003) for the use of products that are specifically-designed, and independently-accredited for use in zero falls applications.

The bare facts of the guidance are that:

1. All waterproofing solutions in exposed roof applications should have a minimum fall of 1:80.

2. High performance liquid applied waterproofing solutions can accommodate ponding water without detriment to the waterproofing integrity of the roof. Indeed, certain systems are “specifically designed for permanently submerged applications.”

3. Independently-accredited high performance liquid applied waterproofing can be used at zero falls in buried applications.

4. “Inverted roof decks should … be constructed to the designed falls without back-falls”.

The Guidance Note does not therefore state that inverted roofs should be constructed to positive falls; but rather to designed falls. As acknowledged in the Guidance Note, designed falls can include zero falls – provided that an appropriate waterproofing solution, such as Hydrotech MM6125 monolithic membrane, is used. This solution benefits from:

– BBA approval for both use in zero falls applications and as a damp-proofing membrane

– A proven track record stretching back more than 50 years and with more than 180 million square metres installed worldwide

– NHBC acceptance for use in zero falls applications of inverted or buried roof systems

Clearly, not all waterproofing solutions will be suitable. For example, there are cold-applied liquid waterproofing solutions that are moisture permeable. Their use in an inverted build-up would introduce the risk that a pressure differential (attributable to the mass of insulation, ballast and any ponding water above the membrane) could force moisture downwards through the membrane into the underlying construction.

However, through the specification of an appropriate solution, the waterproofing integrity of the roof can be assured at zero falls – in both buried and inverted applications.

Thermal performance of insulation on an inverted roof

The Guidance Note also raises concerns regarding the performance of thermal insulation within an inverted roof; highlighting that any water ponding below the insulation would be detrimental to the thermal performance of inverted roofs. This is indeed true. However, widely-marketed insulation and water reduction layers are available with independent (BBA) accreditation specifically for use in inverted roof applications with zero falls. Indeed, the accredited water reduction membrane had zero water penetration when tested over an 8 hour test period in accordance with ETAG031 (Annex C).
The Guidance Note states that “as the quantity of ponding water on a roof is usually unknown it cannot be taken into consideration when calculating the U-value.” However, prior reference has been made in the same document to the fact that BS EN ISO 6946 – the European
norm that prescribes U-value calculation conventions – includes a corrective factor (fx) specifically to account for any water penetration. Therefore, water penetration can be accounted for within the U-value calculation at design stage. As a result, where water penetration is reduced or eliminated by incorporating an accredited water reduction membrane, the thermal performance of the system in practice would actually typically exceed the designed performance level.

To summarise:

Buried and inverted roofs can be designed with zero falls using high performance liquid waterproofing (e.g. Hydrotech MM6125) that has the specific BBA-accreditation.

Standard (ISO) U-value calculation methods can account for the thermal impact of water below inverted insulation. Yet, this impact is limited through the specification of inverted roof thermal insulation solutions that are BBA-accredited in zero fall applications.

Alumasc is pleased to be supporting a gift appeal for children aged 0-18 years old run by St. Helens Council’s Children and Young People’s Service. We have chosen to support this particular appeal because our head office is located in St. Helens and therefore we are providing gifts for children within our local community.

To bring smiles to the faces of those who aren’t as lucky as most of us, the appeal asks people to buy an extra gift whilst doing their Christmas shopping and to drop it (unwrapped) at one of the local drop off-points around St Helens.

Councillor Sue Murphy, Cabinet Member for Schools and Lifelong Learning said:

“For many of our young people and their families these may be the only gifts they receive.  I would like to take this opportunity to thank all those people who contribute to the project to ensure a happy Christmas and for bringing such joy to many young people.”

Staff from Alumasc have come together in previous years for similar causes. Last year we supported the Real Radio and Smooth Radio’s Christmas Toy Appeal in a big way and we are hoping for an even bigger success with staff coming together to support this local cause this Christmas.

Linda Sweeney from Alumasc says:

“This is such a worthwhile initiative to support. There are children out there who won’t get a single present this Christmas for one reason or another. Knowing how much other children will receive this Christmas, it is great to help those less fortunate by giving them a special gift and making them happy.”

If you wish to get involved in bringing the magic of Christmas back to the lives of local children in St Helens then please read the guidelines provided on the St Helen’s Council website: http://www.sthelens.gov.uk/newsroom/2014/11/13/christmas-toy-appeal/

NatureMat®, developed exclusively by Blackdown, is a high quality pre-cultivated Sedum carpet consisting of a biodegradable base layer, a specially formulated substrate layer and a plant layer of selected Sedum species that are randomly sown and grown to maturity in our fields in Somerset, achieving a minimum 90% plant cover.

Applications

Green Roofs – laid onto a minimum 50 mm depth of substrate, NatureMat^® is particularly suited to the planting layer on sloped roofs and/or to achieve an ‘instant’ greening effect. Ground Cover – providing vegetative cover on areas that are either difficult to plant or to maintain (e.g. embankments, roundabouts, tramway beds).

BENEFITS

Once established, NatureMat^® requires minimal maintenance and no watering. NOTE: If installing during summer months, irrigation is required until plants are established (typically 6-8 weeks). NatureMat^® stabilises the substrate layer without the need for mulching. Quick and easy to install, providing an instant green covering. NatureMat^® prefers light, well drained sites but will tolerate most conditions except waterlogged or densely shaded areas.

AVAILABILITY

NatureMat^® is supplied as standard in 1 x 1.5 metre rolls, available on a 5 day typical lead time. NatureMat^® can also be grown to the client’s particular requirements (Note: lead times apply – subject to plant species, time of year and quantity required).

For further information on NatureMat^® and other Black Down Green Roof Products, please call Alumasc Roofing on 03335 771 500.

Following Blackdown Green Roofs initial installation of the green roof at Roundabout Cottage Salisbury in February 2014, Blackdown has continued to provide high quality maintenance of two roof areas.

The roof was initially planted with sedum plugs, a diverse selection of over 25 species of hardy succulent plug plants, supported by a minimum of 70mm of extensive substrate and 25mm drainage layer. This provides attractive plant cover with a range of colours, shapes, heights and flowering times and periods. Maintenance is necessary to ensure the initial establishment of the green roof’s planting.

It is recommended that the installing contractor retains responsibility for the roof’s maintenance during the important early stages of establishment and preferably beyond.

A variety of wild flowers, herbs, grasses, alpines and bulbs can equally be incorporated; varying the substrate depth to suit (70-150mm).

For further information regarding Blackdown Green Roofs call +44 (0)1460 234582 or email: info@alumasc-exteriors.co.uk

Supported by The National Federation of Roofing Contractors (NFRC) – the UK’s largest roofing trade association – the Green Roof Organisation (GRO) has unveiled a new and updated GRO Code for green roofing. The revised code is designed to provide assistance for anyone who is involved in the design, specification, installation or maintenance of a green roof.

First published in 2011, the GRO Code is intended to be a code of best practice and to serve as a guide for behaviour and standards relating to all matters in green roofing. This latest update contains more detailed information on meeting the requirements of the London Plan Policy, together with added guidance on substrate installation and waterproofing.

The revised GRO Code reflects the growing movement by councils and local authorities throughout the UK, including the London boroughs, that now expect green roofs to be designed for new developments, where feasible. As such, it provides an enhanced ‘Living Roofs and Walls’ technical report supporting the London Plan Policy that was first unveiled in 2008. This document provides guidance in helping London combat the effects of climate change and recognises that green roofs have the potential to improve London’s resilience to climate change by reducing storm water run-off velocity and volumes, and by increasing the cooling effect during London’s hotter summers. They also bring many other wider environmental benefits.

Regarding green roof substrate installation, the GRO Code provides guidance on the size of substrate sacks required for certain projects and states that they should be disposed of once the substrate has been discharged at roof level. The method choice of lifting substrate up to the roof level, and its subsequent dispersion of it across the roof, has significant access, budgetary and scheduling implications and is subject to the size of project. Substrate should be applied to the required depth (including the appropriate settlement volume) using grading bars. Depth checking should be undertaken throughout the installation. Once the green roof is installed it should be saturated to capacity using suitable temporary irrigation equipment prior to on-going temporary irrigation depending on time of year.

When it comes to waterproofing, the revised GRO Code now states that in all applications the primary waterproofing layer is critical to the successful performance of the roof as a whole, therefore its function and performance characteristics, and its suitability for use within a green roof system must be assured. At a minimum the specified waterproofing system should be certified to FLL Guidelines against root resistance and/or be covered by British Board of Agrément (BBA) Certification for green roof applications. A wide range of waterproofing options fall within these requirements including reinforced bitumen systems, hot melt monolithic systems, single ply systems, liquid applied systems and standing seam aluminium systems. Guidance is also provided on waterproofing inspections.

Commenting on the latest GRO Code, Simon Poe, Business Operations Director at Alumasc Roofing and a member of the GRO Advisory Technical Group 2013 said:

“Research has indicated that green roofs respond differently to the environment in which they are installed. UK green roofs will therefore perform best if they are tailored to the environment in the UK.

The publication of the inaugural GRO Code in 2011 was a positive first step in the pursuit of good practice in the design, supply, installation and maintenance of UK green roofs.”

Simon adds: “The new edition of the Code demonstrates the industry’s desire to further enhance the quality of green roofs in the UK. The Code informs the decisions of professionals that specify, manufacture, install or maintain green roofs through broader and more detailed guidance. In future, the Code will underpin further enhancements; leading towards an ultimate ambition of prescribing acceptable ranges of performance for components on a quantitative basis.”

Ray Horwood CBE, Chief Executive of NFRC concludes:

“Green roofs perform a vital role in helping cities adapt to the effects of climate change. However, green roofs can only provide these environmental benefits if designed and installed in a way that ensures that minimum performance criteria are met. This code therefore highlights the important green roof design, installation and maintenance considerations and provides guidelines as to how they can be accommodated in the final green roof scheme.”

GRO was founded circa 2008 and represents a partnership of industry (green roof manufacturers and installers) and stakeholders, coming together to develop guidance for the specification, design, manufacturing, installation and maintenance of Green Roofs. The first publication was the GRO Guidelines in 2009, followed by the GRO Code in 2011.

Alumasc is pleased to announce that Blackdown Green Roofs, part of their Roofing Division, has won the Green (Vegetated) Roof Contractor of the Year category at the NFRC Scottish Roofing Contractor Awards 2014. The award recognised Blackdown’s expert green roof installation at SECC, The Hydro project in Glasgow.

The £125million SSE Hydro is a state-of-the-art entertainment and sporting venue. The Blackdown Intensive Green Roof system was specified by Foster & Partners as they were looking for a sustainable solution to help with the strong design features of the building’s entrance. 37,000 Lonicera Nitida ‘Maygreen’ shrubs, planted to form a thick, hardy green mat over the low level ‘skirt’ was utilised to achieve the desired effect above the entrance of the arena. The installation required that the planting system be fed on a regular basis, therefore an automatic irrigation system was installed to ensure that the planting is permanently fed and watered with minimal manpower requirements.

Simon Poe, Business Operations Director for Alumasc Roofing commented:

“There were a variety of challenges on the scheme which were overcome by Blackdown’s Technical Support team. The Hydro is a high profile venue that featured prominently at this year’s Commonwealth Games, therefore is was essential that the installation was completed successfully, on time and within budget.

Blackdown specialises in the design, cultivation, supply, installation and maintenance of lightweight planting systems for green and biodiverse roofs and their expertise was certainly demonstrated on this project, making them a deserving winner of this award”.

For further information on Blackdown Green Roofs click here, alternatively please call +44 (0) 3335 771 500.

Alumasc has recently completed a new step-by-step guide to installing the Hydrotech MM6125 Hot Melt Waterproofing system.

Hydrotech is a 6mm thick rubberised bitumin blend which is heated and then combined with a polyester fleece and protection sheet to form a weatherproof layer.  It is used for zero falls waterproofing on inverted green roofs, blue roofs and hard landscaped podium structures in new build applications and is ideal for application over complex roof details and penetrations.  Hydrotech has a 100% bond to the roof, so water cannot track beneath.

The video illustrates that Hydrotech is fast and simple to apply due to the fact that each individual part of the installation process is covered, with particular attention being given to:

• Health & Safety
• Required tools
• Heating to working temperature
• Bond test
• Upstands
• Detailing
• Pipe penetrations
• Membrane application
• Reinforcement
• Protection sheet
• Depth gauge
• Electronic leak test
• Insulation
• Separator sheet
• Paving supports and slabs

To find out more about Hydrotech Hot Melt Waterproofing Systems click here or call +44 (0) 3335 771 500.

Alumasc Roofing would like to congratulate their Regional Managers for the South and North, James Donovan and Neil Delve, on successfully completing their gruelling 265 mile London to Paris bike ride. They were joined by two friends, Peter Kirkby and Colin Green.

The ride was kindly sponsored by Alumasc’s key supplier of bituminous flat roofing membranes, Derbigum.

Day 1

James and Neil began the ride in Greenwich Park and continued through South London, Kent and on to Dover. They then crossed the channel to Calais for their first night’s sleep after this first 75 mile leg of the journey.

Day 2

The longest day, covering a distance of 80 miles along the Northern French Coast.

Day 3

The most scenic section of the ride – 60 miles of rolling French countryside and peaceful quiet roads.

Day 4

The final stretch was from Beauvais to Paris, a shorter ride of 50 miles with a spectacular finish into Northern Paris through the business district, onto the Arc De Triomphe, then finishing at the Eiffel Tower.

James Donovan Says: “A fantastic experience and some great memories.  Many thanks to our colleagues at Derbigum for their generous support.”

If you would like further information regarding the Derbigum then contact Alumasc click here or call
+44 (0)1744 648400.

Alternatively download the brochure by clicking here

Nottingham Trent University is one of the largest universities in the UK, with around 28,000 students spread over three campuses.

As part of a recent refurbishment programme at the Clifton Campus, the roof of the Clifton Library building was fully stripped and replaced with Alumasc’s Derbigum Olivine mineral roofing membrane.

Alumasc’s expert technical team carried out a condition-based survey of the existing roof and put forward a complete design package to be installed by M&J Roofing Ltd.

Derbigum Olivine was identified as the most appropriate waterproofing solution which offered added environmental benefits. Derbigum Olivine is a bituminous membrane with a naturally occurring mineral upper layer that neutralises CO² in rainwater, via an irreversible chemical reaction. The membrane boasts a 30-year life expectancy and is 100% recyclable.

Alumasc’s full system solution also included their Fascia system, Rooflights and Harmer Roof Outlets.

Alumasc provided a full re-design of existing falls to ensure adequate drainage could be achieved on the new roof.  This included additional insulation being laid to the falls of the internal water outlets – which in turn increased the perimeter detail, creating the project’s greatest challenge.

M&J Roofing’s MD Peter Henrickson, explains:

“Insulation was incorporated into all of the edge details to avoid cold bridging and the potential for condensation. To address this issue, the increased height of the edge detail was covered by a bespoke Alumasc aluminium polyester powder coated fascia board, supplied in a colour to match the new window installations.”

Work also had to be scheduled around other contractors working on site and in addition, staff and students needed to remain in situ throughout the installation. In support of M&J Roofing and to keep the University up to date at each stage, Alumasc’s technical team conducted weekly site inspections, carrying out both written and photographic reports.

M&J Roofing installed a total of 1000m² of Derbigum Olivine, resulting in the library being a much more comfortable space for students and staff to work in, with the new roof also boosting the building’s environmental credentials.

Project Manager Dean Throop from the University’s Estates & Resources Department, comments:

“The new roof is a robust specification to ensure the water integrity of the building, whilst also helping us to reach our 2020 target of a 48% reduction in CO².  I had no reservations about using Olivine, which is backed up by a full Alumasc warranty.  The Clifton Library is one of the most heavily used buildings on the campus and it’s reassuring to know that we have greater protection from water ingress, as well as the additional benefit of boosting NTU’s sustainability.”

If you would like further information regarding the Derbigum Olivine Membrane then contact Alumasc on +44 (0)1744 648400.

Alternatively download the brochure by clicking here

The National Federation of Roofing Contractors (NFRC) Scottish Roofing Contractor of the Year awards recognise and reward outstanding standards of workmanship and technical expertise in the roofing industry within Scotland.

Alumasc Roofing Systems entered the SSE Hydro entertainment and sporting venue as their roofing project for contention. The intensive green roof system on this landmark Foster & Partners designed project was supplied and installed by the company’s green roof specialist, Blackdown. It was announced that this project is a successful finalist under the Green Roof section.

The installation at the SSE Hydro presented a number of challenges due to the varying pitch of the roof and the requirement for the planting system to be fed on a regular basis.

The roof is circular in plan, but undulating in section, therefore it constantly changes gradients in all directions; up to 520 in certain areas. To manage this, the scheme required retention measures to be installed by a third party. Blackdown then installed the substrate, which was blown into special filtration socks on the roof, creating a skirt.

Paul Otway, Head of Contracts at Blackdown, comments:

“Due to the fluctuating pitch of the roof, from between 8 and 520 degrees, we worked closely with our supply partners to devise an innovative solution for the delivery and application of over 1000m3 of substrate required for the roof. Our successful methodology meant that manual handling of materials was kept to a minimum and the installation was completed within the timescales agreed.”

Over 37,000 individual Lonicera Nitida ‘Maygreen’ shrubs were contract grown over 18 months for this project. These are broadleaf, evergreen plants that are native to China and are often used for bonsai. Blackdown operatives planted each individual shrub by hand, creating a dense, evergreen landscape that skirts the main facade of the arena.

Blackdown also supplied and installed an automatic irrigation system to ensure the shrubs are fed and watered with minimum manpower requirements.

A combination of Blackdown’s design, grow and supply expertise helped this project become a huge success, hence it being a finalist for this prestigious award.

Judging was undertaken by a panel of independent professionals and the winning projects will be announced on 24 October 2014 at Trades Hall, Glasgow.

For more information on Blackdown’s green roof products or services, please call 0333 5771 500 or email roofing@alumasc-exteriors.co.uk