SIPS stands for Structural Insulated Panels. These panels come in a number of different forms and are gaining traction as a fast and economical way to build. Like a lot of different “new” building methods, SIPS have actually got quite a long pedigree. They were first investigated by the Forest Products Laboratory in Madison, Wisconsin as part of a project by the US Forest Service to try and slow down the alarming rate of tree clearing occurring.
The first recorded house built using a SIPS panel system was in 1937 when a home was built from the panels designed in the research mentioned above. This house stood until 1998 when it was knocked down to make way for a new building. Many architects picked up this technology in the 30’s and designed buildings using it, such as Alden B Dow and Frank Lloyd Wright.
In 1947 another house was built using various types of skins from plywood to paperboard (similar to the modern day MDF) over a corrugated paperboard core. Not surprisingly when the building was dismantled in 1978 most of the panels retained their original strength, however the paperboard clad panels where not so structurally adequate anymore!
WHAT ARE MODERN DAY TYPES OF SIPS
So what is the main design characteristic of SIPS panel?
They are essentially two sheets of material sandwiched over a foam chore….simple! They are used in all sorts of construction from cool rooms (Usually Steel or Aluminium cladding with EPS core) through to residential homes (usually OSB – oriented strand board with an EPS, expanded polystyrene or XPS, extruded Polystyrene core). What makes SIPS so great is that they are essentially like an I-beam in that they have the two sides separated by a core which makes them incredibly rigid over large spans.
SIPS Panels come in various thicknesses depending on the insulation and/or structural rating required. Like and I beam, a lot of their “stiffness” comes from the distance between the two outer skins (flanges in the case of the I beam). Their load bearing capacity and strength against racking forces (the forces that could blow a house over in extreme cases) means that they can be extremely versatile for construction.
PRO’s and CON’s of SIPS on your next project
- While this issue can be overcome on external walls by adding an exterior cladding, the low mass and high stiffness of a SIP often results in low performance in respect of sound attenuation. Internal walls built using a SIP typically achieve a weighted sound reduction of less than 30dB. This is particularly noted at mid-frequencies (talking level noises) so they arent great for internal walls. A standard timber frame wall lined both sides with 10mm RE plasterboard achieves a marginally higher rating even with out insulation (90mm Stud depth) as in the table below from the Gyprock Red Book;
- Difficulty with changing design or layout on the fly. Commonly SIPS are made offsite in a factory and delivered to site to for assembly. Altering SIPS onsite is usually either forbidden or strongly discouraged as it can undermine the structural adequacy of the units. This is worth bearing in mind as I often find minor changes being requested by owners to internal layout during construction.
- While more expensive to purchase, a SIPS house represents a huge saving in site time and site labor. These savings arent limited to just labor cost. The savings can flow onto areas such as;
- Site Hire costs (toilets, offices, fencing, hoardings)
- Less waste to be removed from site – so less skip bin charges
- Shorter build – less time for the client paying interest and principle payments on their financing without getting use of the building
- Lower change of weather affected schedules – less days on site, lower the likelihood of having the house open bad weather
- Panels can be used for the three major components of the build – floor (in a raised floor sitaution), walls and roof. All of which contribute to the above point
- Bracing ability against wracking forces. Ever been in a house on a windy day and it creaks? This is caused by movement in the walls as a result of the window pushing on the house. These loads are carefully engineered for, however the full OSB skin of a SIPS gives you the highest bracing capacity possible.
- Higher quality sealing of the wall system against air leaks and drafts. This is achieved because a SIPS foam core filly seals against the OSB and end timbers, creating a perfect seal. In a regular stud frame situation this is harder to achieve using bulk insulation, and you end up relying on 10mm thick plasterboard to create the seal between inside and out.
Below is a great explanation video about the products from SIPS Industries. If your thinking of building and want to investigate using SIPS Contact Us today for a free consult.