SIP's structural insulated sandwich panels

The 41 solid, interlocking roof and wall panels can span long distances unsupported. They provide a painted exterior surface, insulation and sound proofing and a painted interior surface all at once. As with the steel frame, the higher cost of materials is offset by lower labour costs and a simpler / faster build. In the rainforest fewer joins means less potential for leaks during torrential rain.

The roof could be made from just 7 - 1m X 14m X 150mm corrugated steel / foam / smooth steel SIPS panels. Access restrictions meant that 14 panels were used for this project. Sites with conventional access could use just 7 longer panels for the entire roof. Another 7 roof panels were used for the roof over the rear balcony.

The 20 - 1.2m wide windowless wall panels protected the east and west walls from the main weather direction and excessive heat. Future additional windows could be added in any shape or size simply by cutting a hole in the SIP's panel and inserting a window frame.

All panels are directly screwed into the steel frame, no pre-drilling. To make life easier a length of 4mm thick RHS is welded along the top of the 250UB31 roof frames so you don't have to screw into 10mm thick steel.

Our panels were supplied as rectangles. Using a steel frame makes angles precise so it should be possible for a panel provider to factory cut wall panel at the 7.5 degree roof pitch angles. In this symmetrical design angle cut panels could be used on alternative sides (you would have to install the second wall from the opposite end) and there would be no waste!

This design added 4 triangular “fins” to the balcony corners. The trapezoidal shape breaks the rectangular look and serves a number of additional useful functions. The triangular “fins” provide shelter from the weather on the balconies. They are particularly useful in cyclones. They help inset and protect the windows. They create wind turbulence, reducing the destructive force and pressure of laminar wind flow. They reduce the likely-hood of windows being sucked out by disrupting corner pockets of low pressure.

Panels needed to be brought down a narrow rainforest. To accomodate high rainfall extra panels were used for a lower roof over the rear “utility” balcony. On a less challenging site fewer longer panels could be used. In locations where access is easy and heavy rainfall is not an issue Studio Nimbus could be built with as few as 29 panels. The concept design is fast, simple and robust. Several years on we highly recommend the use of SIPs panels in construction and have experience no downside to their use.

Maintenance of SIPS in the Rainforest

The smooth vertical steel SIPs surface is essentially self-cleaning.  About every two years we use a little backpack sprayer and spray the vertical walls with a dilute mixture of swimming pool algaecide, detergent to reduce surface tension and a product for cleaning plastic water tanks called Tricleanium maybe 50mL of each in 5-10 litres of water. This method removes anything adhering to the wall. The solution works best on dry walls. Spray it on and leave it for the rain to wash off some time later. This preventative work results in walls remaining smooth and shiny. As the roof is our primary water supply we give it a wash/mop once a year to maintain water quality. When doing this cleaning we divert the downpipe for a short time.