Mark Brinkley, author of The Housebuilder's Bible, the best-selling book on construction for builders and self-builders, is revered in building circles for his advice and expertise: when he talks, people listen.
Recently, as revealed on his much-read blog, he visited two self-build structural insulated panels (SIPs) homes erected by SIPS@Clays in Yorkshire and Lancashire using Kingspan’s TEK building system. He’d been invited by Andy Porter of SIPS@Clays to check out the insulation properties and thermal efficiencies of SIPs: neither house had a conventional heating system, just wood-burning stoves.
He was suitably impressed. “In the absence of any genuine Passive Houses in the UK so far, these SIPs homes stand out as being as close to the new paradigm as we are likely to get in the next few years,” he wrote. “They look to be providing comfortable living conditions with a minimal energy input, which is, after all, what this low energy thing is all about.”
Although SIPs have been around for some time in the UK, it’s only in the last couple of years that they’ve really started to grow in the construction market. With super-fast build times and excellent insulation values and airtightness, they’ve proved ideal for residential housing developments and popular with housing associations demanding strict build criteria.
The fact that developers can now market SIPs-built homes on the basis of their thermal efficiencies is a major selling point. “We’ve just completed a project for a developer in Halifax who’s selling the homes based on 80% savings in fuel bills,” said SIPS@Clays’ Andy Porter. “SIPs might not be the cheapest system, but if the houses are marketed in the right way, they can be highly desirable. As the Code for Sustainable Homes kicks in, developers will have to look at new ways of building their homes – SIPs might be the answer.”
There’s no doubt that, for thermal performance, SIPs is one of the most efficient building systems around. “When it comes to the Code for Sustainable Homes, if you look at the calculation process, there’s a huge amount of points given for thermal performance and airtightness,” said Jeff Tomlinson, business development manager for Kingspan Off-site. “It’s played into our hands in terms of the advantages SIPs can deliver.”
Hemsec, for example, is seeing a lot of interest for SIPs as a backing system for various external finishes in high-rise building, schools and educational usage and low to medium-rise apartment blocks.
“Most recently, we’ve been getting interest from housing associations, based on the product’s overall environmental performance,” said Hemsec’s Richard Daly. “The fact that we now have a product that has a U-value of 0.1 is a big selling point.”
Andy Porter agrees. SIPS@Clays supplies and erects the Kingspan TEK system and Porter has seen a growth in business based on the SIPs timber frame system’s ability to create a highly insulated and airtight building, guaranteeing excellent levels of thermal efficiency required for
the property to be almost wholly self-sufficient.
“The benefit to the customer is that the finished product will require very minimal heating. It’s the air tightness which is crucial: the Kingspan TEK panel is achieving two air leakages per m2 whereas traditional blockwork is lucky to achieve 10.”
Meanwhile, Mark Jenkins, business development manager for SIPs at Palgrave Brown, regards the company’s SIPs system as a “next generation product” and an indicator of the direction the construction industry will take.
“To complement it, we are including more products within our offering, including supply and fix of stairs, external claddings and mechanical ventilation and heat recovery systems,” he said. “We envisage development of different insulation materials and possibly also availability in a range of thicknesses, to give a choice over degree of thermal efficiency.”
The Palgrave Brown SIPs Building System combines SIPs panels with a full range of engineered timber products for a complete floor-to-roof solution. SIPs are 142mm-thick panels consisting of two layers of OSB filled with CFC/HCFC-free rigid urethane insulation.
However, believes Jenkins, site workers still need to get to grips with the speed of the erection. SIPs incorporate all the benefits of modern methods of construction, as the panels are manufactured off-site and go together extremely accurately for fast build times.
“It’s not unreasonable to expect that a typical four-bed house can be watertight for the follow-on trades within eight days,” he said. Palgrave Brown offers training for
follow-on trades who work on SIPs projects.
“Essentially, ‘think before you cut’ is a useful maxim – because the system is manufactured to such a high
spec and with high levels of airtightness, the panels shouldn’t be cut to install services post-construction
without careful consideration,” said Jenkins.
Porter agrees. “SIPs are all about geometry – checking diagonal dimensions so that when the roof is craned into position, it fits. That said, it’s not an easy thing to get into: if you think SIPs is going to be easy, you’re mistaken. You have to know what you’re doing. With the tolerances you’re working to, it’s not as easy to correct them on site as it is with timber frame.”
Training remains a priority. Kingspan Off-site has teamed up with the CITB to put together a training course for SIPs. “So far, around 500 people have been on the course,” said  Tomlinson. “We have 30 or so people going through the training programme each month.”
There’s no doubt that SIPs should feature strongly in a zero carbon future, as they tick all the right boxes for thermal efficiencies and airtightness, all of which contribute in reducing energy consumption – it’s a straightforward way to provide thermal efficiency.
“For housebuilders, one of the main benefits of the SIPs system is that the low U-values combined with excellent airtightness make it easy to improve on carbon emissions ratings needed to meet the requirements of Part L, giving greater design flexibility,” explained Jenkins.
And, he added, because of the high level of insulation as standard, the system complements low-energy buildings and functions extremely efficiently when combined with mechanical ventilation and heat recovery systems or renewable heating solutions such as heat pumps or solar thermal water heating.
“If you’d asked me what the future of SIPs was six months ago, I would have said the sky’s the limit,” said Tomlinson. “But the recent slowdown in the building industry is having an effect on every type of construction.
“Having said that, I think particularly with the Code for Sustainable Homes, it’s far easier to build using a modern method of construction like SIPs and meet a high level of the Code than it is to do it with masonry. The market will grow – and quickly – as the Code starts to have more of an impact, particularly for housing and the education market.”

Kingspan Offsite's TEK panel is achieving two air leakages per m2

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