Improving the Fabric Efficiency of Houses

Richard Kinloch, National Technical Sales & Specification Manager of the Keystone Group, looks at the role of innovative new products when improving the fabric efficiency of houses.
Richard Kinloch Specification Manager Keystone

“It is well documented that we have a national housing shortage in the UK, with pressure coming from the government to boost the number of new homes built in the UK. Due to this, it would seem the government have taken their foot off the green pedal with the delay of ‘zero carbon’ until 2020. Even with this reduction in the green agenda, housebuilders still have a challenge on their hands to meet the current, more stringent building regulations, as we strive for more energy efficient new homes.

Improving Energy Efficiency

On the continuous Journey to 2020, housebuilders have needed to review house designs to comply with the higher levels of energy efficiency as set out in Part L 2010 and more recently in Part L 2013 Building regulations. In Part L 2013 (conservation of Fuel & power), Fabric Efficiency standards have been introduced to ensure that building fabric is improved and to discourage the use of excessive and inappropriate low carbon or renewable trade-offs, which have limited life spans.

There is a strong argument that focusing on the fabric of a building is the most cost-effective, reliable and robust method of achieving compliance with future building regulations, as getting the fabric right will save energy throughout the whole life span of the house.

As designers focus on improving the fabric of the buildings by reducing wall, floor and roof U values, the proportion of heat flow through thermal bridging becomes greater and Part L 2013 has much greater emphasis on thermal bridging as these heat losses were often overlooked in the past. Statistics show that up to 35% of the heat loss in a well-insulated house is through thermal bridges. With 41 different potential thermal bridging junction types being identified within the SAP 2012, it is important that designers address the thermal bridging details to minimise heat loss.

Openings for windows and doors are vulnerable to heat loss through thermal bridging so it is more important than ever to pay close attention to the performance of structural elements such as lintels which are installed in these junctions. Lintels are one of the single most influential contributing factors, which can improve a dwellings SAP calculation and therefore improving the Fabric Energy Efficiency.

To help Housebuilders meet Part L’s requirements and deliver consistent quality in a very competitive market, it is imperative that Keystone, as a supplier to the market continues to invest in product innovations which improve the energy efficiency of a building.

Why is Lintel Choice Vital?

Lintels are, in most cases, the most significant thermal bridges due to the fact that traditional style steel lintels interrupt the line of insulation with a continuous piece of highly conductive steel. This could account for more than 40% of the total heat loss through thermal bridging. Housebuilders now have an excellent solution, thanks to the Keystone Group’s patented Hi-Therm lintel with its dramatically enhanced Psi value. The use of this unique Hi-therm lintel in place of standard steel lintels can lead to an 80% reduction in thermal bridging through the lintels. By making these large savings on thermal bridging, designers gain the flexibility to trim back on other more expensive options (such as wider cavities) yet still comply with the latest Part L 2013 building regulations.

It is essential that specified lintels are backed up by 3rd party certification such as BBA approval to guarantee robust thermal performance, as well as fulfilling their primary function, to provide structural support. Keystone’s Hi-therm sustainability lintel now provides designers, architects and developers a simple, certified and cost effective solution to significantly reduced thermal bridging.

The market’s only ‘Fabric First’ Roof Window

Another Keystone Group product helping to improve fabric efficiency is the Keylite Roof Window, with its patented expanding thermal collar. All roof windows require a ‘gap’ between the window frame and rafters or timber trimmers; however when left uninsulated this contributes to thermal bridging and air leakage. Keylite Roof Windows eliminate this problematic area with a patented built in thermal collar, which expands and fills the gap between the window frame and rafters or trimmers, which also contributes to improved fabric performance within SAP.

Smartroof roof panel system

In traditional structures, the junctions between elements of the building fabric often require special detailing so as not to compromise thermal performance, but Smartroof’s ‘offsite’ factory-insulated panel roof system eliminates voids or cold spots. Detailing at gable, eaves and party head junctions, offer industry leading Psi values and U values which contribute to improving the fabric, offering advantages in SAP calculations.

Taking all of these factors into consideration, I do not think we can underestimate the increasing role that energy efficient products will take in the house building market. Historically, innovation in the construction sector has not been rapid. It is essential, however, that products which make up the building fabric are given careful consideration in terms of their energy efficiency. Products that enhance the Fabric Energy Efficiency of the building envelope and which are backed up by the Keystone Group’s ‘in-house’ technical support can only be of benefit to housebuilders. Manufacturers such as the Keystone Group are embracing sustainable, innovative new products and building methods that will offer benefits to housebuilders and provide guaranteed quality and performance.”

Richard Kinloch
National Technical Sales and Specification Manager