A MODERN METHOD OF CONSTRUCTION PROVIDING THE BUILDING BLOCKS FOR A SUSTAINABLE FUTURE BY TARMAC TOPBLOCK TECHNCAL MANAGER COLIN MARSHALL

Modern Methods of Construction (MMC) are revolutionising the construction industry and fundamentally changing the way we think about building in Britain. MMC offers an efficient way to speed up the delivery of high-quality, sustainable, well-designed buildings for the future, whilst reducing resource consumption. Many public sector bodies are already leading the way in the adoption of these new construction methods, but how can other organisations learn from this and ensure they specify the right MMC to meet their needs both now and in the future?

The term MMC actually embraces a variety of build approaches involving various forms of prefabrication and off-site assembly, as well as innovative site-based methods such as thin joint aircrete blocks like Tarmac Topblocks's Durox System.

The key to selecting the right MMC lies in understanding the issues that surround the use of products in the construction process and the impact they have on the sustainable lifecycle of the property - including its contribution to the surrounding community. There are other practical considerations to take into account, like the manufacturing process, needs of tenants, labour costs and the environment, but it is vitally important to select a method that not only meets current government building legislation, but is robust enough to comply with any potential future changes to these regulations.

With sustainability the hot topic of the moment, a key issue to consider is climate change. Climatic change will have an increasing impact on the way every person on the earth lives, so it is vital that when specifying MMC that organisations carefully consider the materials used in the build. The CIBSE TM36* report shows that the number of days that outside temperature will exceed 25 degrees Celsius will double by 2040, and triple by 2080. Therefore, cooling as well as heating a building will be more of an issue in coming decades, so it's vital to select a construction material that will withstand this inevitable change in our climate. Understanding these future demands is a crucial first step in creating sustainable buildings.

* Chartered Institute of Building Service Engineers TM36 report

Only by looking at these issues and taking a holistic approach to product specification can the public sector deliver real value and ongoing tenant satisfaction. As the industry knows, the success of any construction process is ultimately judged by the individuals who live in it. It is for these reasons that organisations are involving tenants in the selection process, as not only does tenant satisfaction increase, there is also a greater affiliation with the property once it is inhabited. With some methods of construction that do not rely on solid wall, simple issues like the mounting of pictures or wall furniture can prove to be difficult and potentially damaging, creating a need for ongoing, costly maintenance.

Taking into account all the issues above, before product selection can be finalised, there needs to be a thorough assessment of the availability of local labour and the skill sets required to complete the construction process as swiftly as possible. Similarly, in keeping with the issue of sustainability, we need to consider the cradle-to-grave requirements of the construction method, i.e. were raw materials obtained from local UK sources, does the manufacturer use recycled products or by-products and what is the environmental impact generated in the production process. At Tarmac Topblock, more than 97% of the raw materials used in the manufacturing process of our lightweight aircrete blocks are sourced in the UK. Similarly, through our network of UK Plants, all of our products are manufactured in the UK and supplied nationally to optimise construction options and minimise travelling distances. Only by looking at the impact of travel miles from raw materials to manufacture and on-site delivery can the true sustainability qualities of a product can be assessed.

Having made an assessment of all the relevant information and inputs to select the chosen MMC, when awarding the contract or setting up the team required to construct the development, don't pass up the opportunity for training and local job creation, as this kind of boost to the local economy will also contribute to the sustainability of the surrounding community.

For example, at Tarmac Topblock we have a dedicated MMC training facility focused on training the trainers, who in turn pass on their knowledge to train local labour. Similarly, as a manufacturer we are building relationships with colleges that are part of the CoVE (Centre of Vocational Excellence). By conducting seminars and inviting local businesses to interact with students, we have already witnessed job creation and business growth from companies adopting our MMC, known as Durox System with thin joint blockwork.

Putting the manufacturing process to one side, the aim of MMC construction is to meet the Government’s current and future building legislation by developing construction methods that can be used to reduce construction time, promote sustainable development and ensure cost savings. So how does Durox System with thin joint blockwork deliver these benefits and why is it increasing in popularity?

Durox System uses aircrete blocks, making it suitable for use in external solid and cavity wall as well as party walls and partitions. Thanks to larger block sizes and faster-setting thin joint mortar, Durox System offers increased productivity and faster speed of build. In addition, the benefit of a reduced mortar joint means improved air tightness and enhanced thermal performance.

Aircrete construction can also provide a high level of thermal mass, which means the temperature of a building can be optimised all year round and will require much less energy to heat and cool the structure compared to other lighter construction methods such as timber. This has a direct impact on the amount of CO2 emitted over the lifetime of the building because the need for mechanical heating and cooling is reduced, which has massive environmental benefits. Because of this in-built thermal capacity, modern masonry constructions can outperform other methods in terms of the CO2 emissions emitted. Research has established that over a 60-year period, a timber-framed house will emit around 15 tonnes more CO2 than a concrete or masonry constructed home. Masonry construction also benefits from reduced costs for the long-term maintenance and management of buildings.

From a practical point of view, using the Durox System makes it easier for construction companies to achieve the requisite U-values requirements for walls and minimises the amount of insulation required. As the name suggests, Durox System is not just about the blocks. It is a total solution that has been designed to take advantage of traditional masonry construction with a modern twist, combining the use of blocks with a new, glue like mortar and specially designed accessories. Readily available direct from Tarmac Topblock or through local builders merchants, the System itself comprises a number of items to make the overall construction process as swift as possible.

Unlike traditional methods of masonry construction, where a large amount of mortar is required to construct a wall, with thin joint blockwork much less mortar is required, allowing the user to mix batches in-situ, using a powdered mortar mixer. A special serrated mortar applicator or scoop has been designed to make it easier for blocklayers to apply the correct amount of mortar. Due to the quick-setting properties of the mortar there is no limitation to the height that Durox System blockwork that can be built in a day, speeding up the construction process dramatically.

The skills needed to erect Durox System can be easily acquired and require only simple additional instruction and practice - a major benefit to builders and developers alike.

In conclusion, when it comes to the specification of an MMC, there are many varied factors, both technical, practical, social and environmental, which must be taken into consideration. When looking for a product that has both practical and sustainable benefits, Durox System with thin joint blockwork provides a total solution for residential, commercial or civic applications.