WEATHER PROOFING

As with timber frame the resulting structure, once clad or rain-screened, is more than capable of withstanding all that the British weather can throw at it. In this respect it is no different to timber frame but the fact that panels do not shrink or twist as they dry out is an advantage in achieving greater air tightness and reducing call backs to ease doors and seal cracks.

VARIATIONS ON THE THEME

SIPs panels are commonly made from engineered timber products but they may also be made with steel frames set and glued to insulation panels. The structural element is provided by the steel frames which enclose either side of the panel as a picture frame would. The inner and outer steel frames are held apart by the insulation so there is no cold bridging and the insulation provides lateral rigidity. The vertical load is taken on the steel frames so the strength is not really dependent upon the adhesive bond between the insulation and the steel. These panels are very light and may be constructed without a crane but their lightness means that they need fixing properly to the foundations with anchors or rag bolts to prevent the roof lifting them in high winds. Generally a foundation track is fixed to the slab and the panels are then dropped into the track and screwed through from the side. SIPs have been used with great success in hurricane areas so we in the UK have little to worry about provided we don't abandon tried and tested methods.

There are many who believe that SIPs will eventually replace timber frame. SIPs on the other hand have come in on the coat tails of timber frame and many of the early lessons are transferable. Provided everyone in the process has a clear understanding of what is required of them, there is no reason why SIPs should not continue to take market share and make a valuable contribution to U.K house building. The early failures suffered by timber frame, picked up by the television programme World In Action and broadcast in June 1983 killed demand for this type of building at a stroke and it has taken a long time for the industry to recover. Timber frame is once more under scrutiny, this time for implementation of fire protection. It is another indication that bad practice on site can bring down an otherwise healthy industry. Few things in life are certain, except death and taxes, but a television undercover reporting team turning up at the most inconvenient moment must surely come a close second.

Article links:

• SIPTEC  -  The UK's first and most experienced structural insulated panel, SIP manufacturer.
• SIPCRETE  -  Insulated concrete, low cost high thermal mass building system.
• MICRONAL PCM  -  Acquires an active temperature compensation mechanism which ensures ideal room conditions.
• KINGSPAN PANELS  -  A highly recognised brand for insulated cladding panels in the markets which it services across Europe.