Aluminium decking offers a wide range of advantages in comparison to more traditional materials such as timber and wood-polymer composite decking. It is ideal for new build and refurbishment projects, due in no small measure to arrival of building regulations in December 2018 which banned the use of combustible materials.
ALUMINIUM DECKING – FIRE SAFETY COMPLIANCE
In a post-Grenfell construction sector, fire safety is now subject to increased scrutiny and stricter regulation. Introduced in response to Grenfell, the Building (Amendment) Regulations 2018 (S.I. 2018/ 1230) and amended Approved Document B and Approved Document 7 Guidance have completely changed compliance requirements for balcony decking. They prohibit the use of combustible materials in external wall systems and balconies.
What are the latest fire safety requirements for balcony decking?
Buildings which have a floor above 18 metres from the ground and are used for residential purposes must use materials that are A2-s1, d0 rated or Class A1 under the European classification system (Euroclass) set out in the standard BS EN 13501-1 subject to exemptions. They apply to new build construction, replacement materials within a refurbishment and projects in which an existing building is being converted into residential use.
How does this affect balcony decking?
Aluminium is A1 Fire Rated under the Euroclass system – the highest achievable score for non-combustibility. Aluminium decking is therefore fully compliant for use on balconies. In contrast, materials with wood elements – including composite decking products – are no longer compliant as they are not A2-s1, d0 rated or class A1 under Euroclass. Neaco’s range of aluminium decking is A1 Fire Rated and has been fully tested to comply with the requirements for Class 0, as defined in Approved Document B, ‘Fire Safety’, to the Building Regulations 2000.
ALUMINIUM DECKING – DURABILITY
Material lifespan is a vital consideration for decking. In the NHBC’s technical guidance, Clause 7.1.4a states that structural elements of balconies should have a desired service life of at least 60 years. Aluminium is corrosive-free and has a recognised design life of at least 60-100 years. One report has suggested that it has an infinite lifespan in internal installations and a minimum lifespan of 120 years in external installations. Timber decking is vulnerable to woodworm, damp, mould and rot. In contrast, aluminium decking is a maintenance-free solution that avoids all the cost and labour of ongoing treatment that are necessary to prolong the lifespan of more traditional materials.
ALUMINIUM DECKING – SLIP RESISTANCE
With the right manufacturing expertise, aluminium decking is also a superior choice for slip resistance, providing safety underfoot for balconies and garden decking. Neaco have designed a range of aluminium decking systems which are engineered to provide a very finely-grooved surface, specifically developed to provide anti-slip performance in the direction of travel. Even with a grooved surface, timber decking becomes increasingly slippery underfoot with the build-up of dirt, with moss and grime. It can become especially hazardous in wet conditions, which is another reason why wood-based decking has become less popular.
How is slip resistance measured?
Two testing methods appear in the British Standards (BS8204): the British Pendulum CoF Test and the SlipAlert test.
The British Pendulum CoF Test measures slip resistance in terms of pendulum test values (PTV)
Pendulum results should be interpreted using the information in the below table.
For a decking manufacturer to use the term “anti” or “non-slip decking”, the PTV must be 36 or above.
Leading wood-polymer composite boards score an average PTV of 58 when dry and 37 when wet.
In comparison, Neaco manufacture aluminium decking systems which have PTV scores of between 78 and 100 when dry in the direction of travel. Even in wet conditions, they still score between 46 and 85 PTV in the direction of travel.
SlipAlert test uses a device to measures the slip risk of floors. The testing mirrors the physics of a human slip. A reading of up to 130 is a low risk of slip; 130 -173 is a medium risk; 173+ is a high risk. The results can be converted into PTV (please see below graph)
Neaco’s aluminium decking systems have SlipAlert scores which are categorised as ‘low risk of slip’ in the direction of travel in both wet and dry conditions.
ALUMINIUM DECKING – LOAD BEARING ON RAISED FLOORS AND BALCONIES
Load-bearing capacity is also an important consideration for raised decks and balcony flooring. Another clear advantage of aluminium decking is structural efficiency – in other words, it is lightweight (1/3 of the weight of steel) yet high in load-bearing strength. Neaco’s Neatdek aluminium decking panels are 15.8kg per sqm, compared to 25.2 kg per sqm for leading wood-polymer composite products.
In the context of balcony installations, load-bearing strength is increasingly important for cost reasons: due to fire safety concerns, steel joists are now widely used instead of timber joists, but steelwork is expensive so substantial savings can be made by using decking that needs less structural support. With Neaco’s aluminium decking systems, joists are only required at centres of between 1200mm and 1800mm (depending on the profile depth) compared to around 450mm for most composite decking. In balcony applications, our aluminium decking has a 1640mm clear span capability.
ALUMINIUM DECKING – DRAINAGE OPTIONS ON BALCONIES
Neaco’s aluminium decking range includes a choice of ‘T-bar’ profiles providing open or closed grilles. They offer a foot contact area of between 74% and 100% whilst allowing rainwater to drain quickly and efficiently below – a combination that is especially useful for balconies.
Any balcony with a floor area of over 6m2 conventionally uses ‘positive drainage.’ – a catchment tray which is installed directly below the flooring, encased within a soffit and fitted with a hopper and drainpipe. Positive drainage has various drawbacks – it is cumbersome, costly and laborious to construct and vulnerable to blockages caused by the accumulation of dirt, sediment and waste substances.
Neaco’s aluminium decking can facilitate an alternative ‘eaves drop’ drainage method which is increasingly favoured by contractors and housebuilding warranty providers. With some of our aluminium decking systems, rainwater can drop directly into a ‘French drain,’ a ground-level trench comprising a perforated pipe which is installed below the ground and topped by a layer of pea gravel. Surface water seeps between the gravel and passes freely through the pipe. It’s an efficient way to divert water away from the building and avoid pooling. Compared to positive drainage, using this form of aluminium decking with a French drain is a lighter, more economical combination which is faster and easier to install.
Neaco also provide aluminium decking with a built-in concealed drainage system which sits discreetly beneath the gaps in the surface and directs rainwater away from the balcony, thereby avoiding water ingress to balconies below and any need for soffits or downpipes.
ALUMINIUM DECKING IN SUSTAINABLE BUILDING
Aluminium has various natural attributes that make it suitable for sustainable building and reducing environmental impact. It is an inert metal and completely impermeable. It is non-toxic and does not release any odours or taint products in contact with them. These properties help to maintain aesthetic quality and reduce pollution.
In architectural specification it is essential to consider the responsible sourcing, effectiveness, durability and potential recycling of any material. Dismantling and recycling or reuse of building components is one of the building performance criteria outlined in BREEAM. Every material has its own degree of recyclability and aluminium is 100% recyclable. It has an extremely high residual value and can be recycled over and over again without loss of performance – there is no difference in quality between virgin and recycled aluminium alloys. It can also be up-cycled if necessary.
Neaco have been setting higher targets each year for the recycled content of our manufacturing output and in 2012 we set a minimum figure of 85 per cent for our aluminium balustrade and decking products. In many cases we are now supplying complete design solutions from as much as 95 per cent recycled material.
The durability and maintenance-free qualities of our aluminium decking also increases the lifecycle of developments and reduces the manpower required to maintain them, providing another positive effect on sustainability.
If you are considering a decking installation and would like to know more about the benefits of Neaco’s aluminium decking range, please send an enquiry to our Technical Team here or call us on 01653 695721.