Structural Insulated Panels (SIPs) can help builders to meet new Part L Building Regulations, and work towards the Future Homes Standard, through exceptional thermal efficiency and reduced U values. 

From 15^th June 2022, the amended approved document Part L of the Building Regulations for new homes, including self-build, and improvements to existing homes whether planning permission is required or not, stipulates a 31% reduction for operational energy vs 2013 regulations.

The Part L update relates to the conservation of fuel & power. The reductions required in operational energy can be achieved through both the building fabric and the choice of technology (renewables) used in the building. The methodology which will measure the operational energy is the new SAP 10.2. This models the building fabric U values (heat loss over the surface area) and the PSI values (heat loss through the junction).  

Table 1 below outlines the new Limiting (minimum) Standards:

How to achieve the new U values

The new U Values required have been particularly reduced for home extensions, loft conversions & dormers. These U Values can be achieved by using a fabric-first approach which creates improved thermal performance.

Trevor Clements, Head of Business Development at Hertfordshire Building Control put it this way, during the BBA Future Home Standards webinar in November 2021: “There may be a few of you out there who are involved in extensions & alterations to dwellings, where it’s a bit more than a tweak…walls from 0.28 to 0.18 (SAP rating)… it will be interesting to see how designers and industry hit that standard with your traditional cavity walls, brick and block. Are we going to be seeing more use of high-efficiency insulation…because that’s going to be a huge cavity if you are going to be using mineral fibre or fibre glass bats to achieve that mark?”

What are the benefits of using SIPs?

Builders and installers can offer their customers something better and different from their competitors, being able to come closer to meeting FHS and Passivhaus standards and resulting in reduced days in their home needing heating which significantly reduces energy bills. This will make their homes warmer in winter & cooler in summer and directly addresses the ongoing rising fuel prices and fuel poverty.

As the owner of a SIPs home built in 2020 puts it: “It was a total revelation to move into such a beautiful home in the Highlands of Scotland that effectively doesn’t need heating. This makes it a comfortable house to live in as it also means there are no rapid fluctuations of heat.” The home meets, if not exceeds, current Passivhaus standards, as do many SIPs-built properties.

Other benefits include;

• Training. According to Richard Smith and Dan Hicks of the NHBC (Building for Tomorrow technical conference), bricklayers and other trades will need training because the industry is moving mostly from 100mm to 150mm cavities and beyond
• Impact on associated materials such as wall ties being too short
• Delays in supply of traditional materials (currently barely impacting SIPs, which are generally available from Hemsec within 2-4 weeks of order)
• Rising costs of materials, particularly imported
• Speed of build and few if any delays due to weather (superstructure is up in around two days)
• SIPs give greater accuracy of material sizes versus design
• SIPs give greater versatility in design, particularly with large, uncluttered roof spans