Statistics have shown that up to 35% of heat loss in a dwelling is through thermal bridging [see also: ‘Thermal Bridging and Psi Values: An understanding’]. Selecting the correct Lintel can be one of the single most influential contributing factors that can improve a dwellings Standard Assessment Procedure (SAP) calculation. By improving the lintel Psi value alone, we can significantly improve the SAP calculation, negating the need for more expensive solutions such as wider cavities or costly renewable technologies. Here we look at the many benefits of specifying Hi-therm when trying to achieve thermal efficiency.
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. The Keystone Hi-therm sustainability lintel provides designers, architects and developers a simple, certified and cost effective solution.
Here are the top benefits of specifying Hi-therm lintels:
The only one-piece lintel to comply with 2013 Part L building regulations
Standard lintels are made of a highly conductive material: steel. Thus, they contribute significantly to the buildings overall thermal bridges. The GRP component of the Hi-therm Lintel means that it has much lower conductivity than steel therefore forming a thermal break reducing total heat loss substantially through the lintel. In fact changing from a steel cavity wall lintel to a Hi-therm Lintel could improve the lintel thermal bridging by up to 80%. The Hi-therm Lintel can achieve Psi value of between 0.04W/m.k – 0.06W/m.K, meaning it is the only one-piece lintel on the market that complies with the Appendix R values within Part L of the 2013 building regulations.
One-piece lintel, bonding two leafs of a wall together. Negates the need for separate lintels
Hi-therm is a one-piece sustainable lintel solution. The Hi-therm lintel bonds the internal and external leafs of a cavity wall together by spanning the intervening gap, this gives a wall more lateral stability. The patented Hi-therm lintel utilises a hybrid design with a galvanised steel component supporting the inner blockwork connected to a GRP component supporting the outer brickwork.
With separate split lintels, double handling is required as the two lintels are installed separately. This solution also requires temporary propping of the lintels, more wall ties to stabilise the cavity, additional cavity closers, complicated DPC cavity tray details and awkward insulation details to ensure all the voids between the lintels get insulated.
The Hi-therm Lintel, however, is installed exactly as a regular cavity lintel, with no extra components needed and no extra labour.
BBA Certification & Technical Support
Hi-therm is the only thermally broken lintel on the market that has trusted 3rd party certification from the BBA, which tests the design, strength, performance, durability and fire resistance to ensure the product is fit for purpose. A BBA approval also gives NHBC acceptance for full peace of mind.
Moreover, we can offer bespoke PSI value certificates or calculations which can be produced for your specific cavity build up for free via our website here. This is a unique service, and will ensure your energy or SAP assessor can gain the maximum performance benefit within the SAP calculations.
Hi Therm does not require a cavity tray Damp Proof Course (DPC)
DPC cavity trays are a tricky detail to install correctly. Hi-therm Lintel does not require a DPC cavity tray*, saving time on installation and reducing the overall cost of the build. The insulation which is factory fitted within Hi-therm also helps ensure consistent continuity of cavity wall insulation without any thermal breaks.
*Unless in areas classified as severe by NHBC
Outperforms stainless steel on price and corrosion resistance
NHBC recommend that Stainless Steel lintels should be used if building within 500 metres of the coast line. Hi-therm is an excellent alternative to stainless steel lintels and has the seal of approval from NHBC to be used a replacement to Stainless Steel. Not only is it less expensive than its stainless steel counterpart, it is also is more thermally efficient. Moreover, with the Hi-therm GRP outer leaf it is more corrosion resistant than stainless steel, making it ideal for any coastal project.