Specifying building products for a sustainable future


‘Sustainability’ and ‘future proofing’ are no longer simply buzzwords for environmentally conscious construction companies. A range of changing economic, social and environmental factors mean that architects and specifiers must reassess the way they create buildings, and take positive steps towards specifying high quality, sustainable building materials that fit these agendas.

There can be no doubt that climate change is one of the major drivers that requires new buildings to be designed with future proofing in mind. Rising summer temperatures and potentially harsher winters will have a significant and lasting impact on the way we will live and work, so specifying products that are capable of creating sustainable buildings that can withstand the effects of climate change has to be a major priority for everyone involved in construction.

You only have to look at the CIBSE TM36* report - which shows that the number of days that outside temperature will exceed 25 degrees Celsius will double by 2040, and triple by 2080 - to understand the true scale of climate change. As these predictions neatly demonstrate, it is cooling, as well as heating a building, that will be more of an issue in the coming decades. *Chartered Institute of Building Service Engineers TM36 report

Stringent Building Regulations and pressure from the Government to create energy efficient buildings has made their thermal performance more important than ever. So when selecting construction products it is important to take into consideration overall thermal efficiency. The thermal efficiency of a building and its thermal mass performance ultimately dictate the ability to minimise the energy used in heating and air conditioning, and the associated CO2 levels.

Block-built properties have high thermal mass potential, particularly if blocks are used to construct internal partitions as well as the external walls. Concrete blockwork will retain heat (and cool) much better than timber and steel frame alternatives. In fact, using concrete blocks as a building material can significantly reduce energy consumption in commercial and residential properties.

Walls make up the largest surface area of a building, so ensuring that walling products have good thermal mass and low U-values is extremely important. Because of the intrinsic high thermal mass of both aircrete and aggregate blocks, they offer specifiers the maximum thermal benefits of any building product. Today, one of the most thermally effective solutions is to use Durox aircrete blocks in solid-wall construction, and combine this with an insulating render. This negates the need for internal insulation, as the relative position of the blockwork and the render help to maximise the thermal mass potential of the structure as well as the reducing the risk of interstitial condensation.

Taking this point one step further, because a building’s environmental impact does not stop once it has been built, an additional area to consider in the sustainability agenda is the ‘whole life impact’ of a structure. This means taking into consideration not just the energy that it takes to extract and process the product, transport it and install it, but the impact that that product ultimately has in the operational life of a building. Research from the Concrete Centre shows that over a 60-year period, a concrete or masonry constructed property will emit around 15 tonnes less CO2 than a timber-framed alternative, thus the whole life performance of masonry built properties makes them a particularly sustainable option.

But creating sustainable buildings is about more than our changing climate and carbon emissions. In the UK, escalating house prices are placing increasing pressure on children to stay in family homes for longer, but conversely, homeowners are less able to finance a move to a larger property. This means that in the future, we’re likely to see more people opting to extend properties or renovations to accommodate a greater number of individuals. Therefore, we need to ensure that new-build homes and refurbishment projects use products that offer real flexibility to owners and architects alike and be sustainable in terms of offering continuing flexibility.

Concrete block based buildings facilitate the easy removal or replacement of some part of the structure, most likely a wall. So if home owners want to extend rooms to add space for an expanding family, or even go green, by installing a wind turbine, having a property constructed using blocks will not only reduce future construction and renovation costs, it ultimately offers more choice.

Sustainability is also about whether a product is fit for purpose. It’s no good if a building has to be torn down after 50 years because the materials used in the first place were chosen on a cost basis, or on short term benefits. Ultimately, this has far worse impact on the environment and is certainly not a sustainable option from a cost point of view.

So selecting construction products and assessing their sustainability, you need to look at durability and longevity. Blocks score highly on both counts, and block built properties can last for hundreds of years. Concrete blocks also have great soundproofing qualities - a big plus when we’re likely to be living in much closer proximity to our neighbours in years to come. It’s also very safe. Concrete is a non-combustible material, and its thermal mass means that in the event of a fire, blocks can absorb heat, thus acting as a fire barrier and giving people vital extra minutes to evacuate.

It is also worth noting that concrete is 100 per cent recyclable. When a building constructed using blocks comes to the end of its life, the material can be crushed and reused - perhaps even used to make new blocks. In fact, our Hemelite blocks can contain up to 90 per cent recycled content. In this way, we can help protect a finite resource and contribute to the future sourcing of UK based raw materials.

For architects and specifiers, modern block products deliver numerous benefits when considering sustainable construction. New product innovation is set to increase choice still further, so the argument for block construction will continue to gather momentum. With the uncertainty of climate change ahead and a continuous demand for new innovative, durable housing solutions, blocks will be an integral part of building a more sustainable future for generations to come.

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Date: 23 January 2009

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Fact 14

Low embodied energy…

Like all concrete, during its lifetime Precast concrete will effectively re-absorb the equivalent amount of energy (carbon dioxide) that was used to create it I the first place! What’s more, using Precast doesn’t require any re-mineralisation (the process of rejuvenating barren soils after they have been intensely forested).

See more in Why Masonry?