ROOF, CLADDING & INSULATION
considered at the outset to get a more accurate picture of the whole life costs of each solution being considered.
MAINTENANCE When render is applied well the initial results are outstanding but the erratic nature of the UK’s weather system means making those results last beyond a few decades is reliant on the skill of an incredibly diligent craftsman. Worryingly, there is also a trend for render to fatigue more quickly in aggressive environments such as coastal regions due to airborne sea salt, which means treatment or replacement is needed much sooner than anticipated. When render does start to crack and develop holes it will either need patching up or even replacing completely – which can be a messy and expensive job. Compared to render,
rainscreen cladding solutions are generally more resilient to what the UK climate can throw at it - including airborne salt in coastal regions. While most traditional building materials have a limited life, the best performing rainscreen cladding systems on the market are designed to retain their functional effectiveness and aesthetic qualities for several decades.
THE ENVIRONMENT As a wet trade, render makes it more difficult for developers to remain environmentally compliant on site than working with factory produced rainscreen cladding systems, which make it easier for developers to meet their obligations towards keeping every part of a building site as clean and safe as reasonably possible. Disposing of waste render can also be difficult as well as expensive due to it being a wet trade. That’s not to say there is no
waste created when working with rainscreen cladding. Most are produced to standard sizes where cutting is often required to meet the architect’s brief, but depending on the scale of job, the third party often cuts panels to size on their premises and delivers them to site ready for installation. Depending on manufacturer
capabilities, rainscreen panels can be produced to bespoke size in the factory – which can substantially minimise the amount of waste created and get the panels installed far quicker.
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WEATHER AND INSTALLATION Weather-wise, render is subject to the unpredictable British climate and cannot be applied if conditions are wet or even too warm – which can lead to costly delays on site. Being unaffected by moisture or temperature extremes, rainscreen cladding systems have a distinct advantage when it comes to avoiding weather delays as they can be installed in all-weather conditions.
SPEED OF INSTALLATION When comparing render and rainscreen cladding on speed of installation on to rear-ventilated systems, installers should be able to cover the same amount of space in less time by working with the latter, which needs to be fixed on to sub-frames using screws, rivets or adhesives. Although rainscreen cladding
installation is still quicker when covering the same amount of space, a render application can be completed more quickly by using modern through colour renders (monocouche) which can be applied in one coat. However, despite this advantage, render still requires a significantly high skill level to achieve a smooth finish to maximise it’s life expectancy. Render does have an
advantage over rainscreen where there is a choice to apply weathering solutions directly onto an external wall – unlike rainscreen cladding which should only be fixed as a rear- ventilated system. But as the
Ian says that the cheapest solution is not always the best and that every project calls for a different technique
industry embraces the Green Deal and continues to meet requisites under other home efficiency schemes, rear- ventilated systems with insulation will become customary practice as this approach better protects a building’s fabric and reduces CO2
SITE SAFETY Even when weather conditions are ideal for construction, it’s hard to control the amount of mess on site when applying render, which makes it more difficult for developers to comply with Health and Safety Executive (HSE) regulations that every part of a construction site should be kept in good order. As a MMC, rainscreen
cladding panels are manufactured to both standard and bespoke sizes. This is a distinct advantage as this capability helps with waste and mess minimisation efforts - making it much easier to protect the workforce.
DECANTING The Green Deal, amongst other home efficiency programmes, has sparked several social housing refurbishments as local authorities and social housing landlords endeavour to meet energy efficiency and decent homes standards. Depending on the scale of the operation and to the extent wet trades such as render are used, many authorities and housing associations have no alternative but to decant affected residents
into alternative accommodation while improvement works are in progress. When considering factors such as re-housing costs and administration overheads, a large-scale render application should be given serious consideration as it could prove less attractive to what it first did on the materials budget sheet. Rainscreen cladding panels
should help clients avoid any resident decanting programmes as they are factory-produced to standard and bespoke sizes, thus creating far less mess than render. They are also much quicker, cleaner and simpler to install than render.
THINKING AHEAD Where there is choice to use render on a project, its cost effectiveness at specification stage goes without question, but depending on the amount required and other highlighted factors, over the life of a building that temporary saving could come back to present more cost outlays further down the line. Furthermore, and subject to the scale of a render project, it’s even possible to cancel out any cost saving altogether before the project is handed over because of all the associated problems it can create at project build stage. Although there is no right or
wrong when it comes to working with render or rainscreen cladding, the need to think well ahead and consider every issue possible could make all the difference between seeing project costs soar or keeping spend expectations in check.
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