Save time and reduce build costs with one-piece lintels

Ciaran McAliskey, Specification Manager (Ireland) of Keystone, Lintels explains why a fabric-first approach is an essential first step to achieving net zero targets…

Energy saving measures and greening homes at speed and scale will be essential if we want to achieve our net zero targets. With thermal bridging accounting for up to 30% of heat loss from buildings, a fabric-first approach is an essential first step. By paying close attention to detailing, we can eliminate some of the issues of poorly performing homes.

With traditional steel lintels accounting for heat loss, understanding how this can be overcome is critical. Taking time for the details and optimising build quality will make a difference in the fabric-first approach and ultimately reduce energy costs. For example, ensuring junctions are appropriately designed and constructed, as this makes a significant contribution to reducing heat loss. In terms of lintels, a thermal bridge occurs when a lintel spans between the inner and outer leaf of a cavity wall, allowing heat loss which ultimately leads to a drop in internal temperature and an increased demand for heating. This can increase the risk of surface condensation and mould growth.

The other concern in terms of thermal bridging is that we are neither building consistently what we design, nor detailing the right products in the right places. There are also issues with site skills and workmanship; when you fail to build correctly it undermines the good work carried out in the first instance. This can lead to a performance gap between as designed and as-built building performance. It’s why these weak spots can significantly impact a building’s heat loss and have a detrimental effect on the overall fabric efficiency of the external wall.


With many two-piece lintels there is an issue with a lack of continuity of insulation. To ensure the insulation is continued all the way down to the cavity closer, it is necessary to cut a piece of insulation to fit beneath the DPC membrane. This detailing is difficult and cumbersome on site and quality control issues can occur. There are solutions to address this. For instance, the Hi-therm+ Lintel is prefabricated and fitted with PIR insulation, ensuring insulation continuity and eradicating poor detailing on site. Unlike a two-part solution – which can add costs and double installation time – the simplicity of a one-piece, structurally superior top hat design assists stability between the internal and external leaves and creates stability throughout the building process.

The Hi-therm+ Lintel has made a significant impact on the thermal efficiency of homes and is specified on many housebuilder projects due to its low cost and improved performance in
lowering carbon emissions within the Standard Assessment Procedure (SAP). Constructing climate resilient homes has never been more important, which is why the Hi-therm+ Lintel is proven to deliver where others cannot, and is unsurpassed in terms of thermal efficiency, buildability and even greater practicality for builders.

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