Independent industry expert and author of ‘The Housebuilder’s Bible’, Mark Brinkley, spends his professional life observing and reviewing construction materials. He describes the history of Structural Insulated Panels in one of his regular contributions to Home Building & Renovating Magazine:
‘SIPs are not a new idea: they have a long and colourful history. The original experiments with honeycomb panel construction went on in the 1930s in the USA, working to some designs by the architect Frank Lloyd Wright. It was a student of Wright, Alden B Dow, who first placed extruded polystyrene (made by his family’s company, Dow Chemicals) inside a SIPs sandwich and used it to build a series of houses in Wisconsin in the early 1950s.Dow and others proved that the concept worked and produced durable, long-lasting homes that were test-built across many climate zones. But early SIPs houses proved expensive to build and SIPs remained something of a curio until the 1980s, when a number of small homebuilders in the USA and Canada started using them, chiefly because they valued the thermal efficiency, the airtightness, and the accuracy of assembly. Manufacturing in Britain began around 15 years ago, after a number of SIPs homes had been imported into the UK from North America.’
‘SIP homes go up much faster than traditionally framed buildings. A properly trained SIP installation crew can cut framing time by 55 percent compared to conventional wood framing, according to a third party study conducted by R.S. Means. …. SIPs are ready to install when they arrive at the jobsite, eliminating the time needed to perform the individual jobsite operations of framing, insulating and sheathing stick-framed walls….
…. Builders can save money through decreased construction and labor costs …. Builders can also significantly reduce jobsite waste disposal and temporary heat during construction. Homeowners that incorporate other energy-efficient features into a SIP home can see utility savings of 50 percent or more….
…. Structural insulated panels are one of the most environmentally responsible building systems available. A SIP building envelope provides continuous insulation, is extremely airtight, allows for better control over indoor air quality, reduces construction waste, and helps save natural resources….
…. The structural characteristics of SIPs are similar to that of a steel I-beam. The OSB skins act as the flange of the I-beam, while the rigid foam core provides the web.’
The U.S. Department of Energy (DOE) reports that SIP buildings are about 15 times more air tight than stick construction. “A SIP house has fewer joints, less complicated interfaces between conditioned and unconditioned spaces, and it is dramatically easier to make it tight,” …. As a result, SIP homeowners enjoy up to 60 percent energy cost savings from both heating and cooling their homes.“Everyone is so amazed by the energy efficiency SIPs provide,” says Scott Bergford, a DOE Energy Value Housing Award Builder of the Year, based in Olympia, Wash. “It only costs an average of $200 to $300 a year to heat one of my homes. That’s anywhere from one-fifth to one-sixth the typical costs for this region, so the savings are pretty significant, and the homeowners love that.”
Respected journalists and industry publications also regularly feature SIPs and the benefits of SIPs versus Timber Frame and other forms of construction:
Structural insulated panels (SIPs) are made up of two layers of oriented strandboard (OSB) bonded around an inner core of insulating material. These precision-engineered panels are prefabricated in a factory, which makes for time and labour cost savings on site. When used for load-bearing purposes, they're suitable for building walls, ceilings and floors. In fact, they're so sturdy that they can be used to create truss-less roofs for liveable loftspace that make best use of available height - we've heard of many self builders who've combined other build methods with a SIPs roof for this reason.
SIPs is also growing in popularity as a wrap-around for structural timber frames, combining this system's airtightness with the charm of internal exposed beamwork. Whether you choose a full SIPs build or a wrap-around, a successful project will result in an exceptionally airtight building envelope.
As the panels are lightweight, pile and pad foundations are appropriate, and will save you time at the construction stage. Experienced teams can erect the structure of a SIPs house in as little as three days (or seven to 10 days for a timber frame with SIPs wraparound). Other timesaving bonuses include pre-cut (or even pre-fitted) door or window openings.
Build speed: Up to 60% faster than conventional timber frame on site, but prefabrication of panels takes around 10 to 12 weeks [during which time groundworks and foundation are usually completed on site meaning the prefabrication period does not affect your build programme]
‘…. Structural insulated panels, or SIPs, are sometimes described as being like timber frame without the timber. SIPs are made by gluing insulation between two sheets of oriented strand board (OSB) to form a tremendously strong wall or roof section, which requires little, if any, further support — in fact, the panels are so strong that they can be used to build structures much bigger than homes. It sounds miraculous, but similar concepts are employed in widely different applications, such as manufacturing aircraft wings, where a body gets its strength from knitting different materials together….
…. Another area where SIPs come into their own is on designs using vaulted or open roof spaces….SIPs provide the capability to span from ridge to eaves with, at most, one intervening horizontal beam, known as a purlin. Thus simple roof shapes can easily and effectively be covered over in a matter of hours…In instances like this, SIPs panels are the most cost-effective method of building….
….Andrew Rowe from Grantham, Lincolnshire, is in some ways a typical SIPs user. He is a professional builder who has built over 50 homes during a 30-year career, always using traditional brick and block construction. This year he chose to build his own house and he decided to use SIPs for the first time. “I am really impressed,” he says. “They’re incredibly quick to build with and have some incredible qualities — so much so that I’m never going back to blockwork again because it’s slow, it’s messy and the process keeps getting interrupted by the weather. Using SIPs on what is a very big house, we’ve gone from groundworks to moving in in just 16 weeks. In addition, the SIPs panels are so accurately made that I have been able to order windows off the plan: they all fitted perfectly.”….’
Source: Mark Brinkley, Home Building & Renovating, www.homebuilding.co.uk