What are SIPs?

What are SIPs (Structural Insulated Panels)?

Structural Insulated Panels, lovingly called "SIPs" (pronounced "sips"), are rigid foam core insulation sandwiched between two sheets of oriented strand board nicknamed OSB (this one is said as an acronym "O.S.B.").

We know... kinda confusing, but keep reading, they're incredible! smiley 

How do SIPs work?

The Expanded Polystyrene (EPS) core has superior insulating qualities because of the inert, stable cellular plastic of which it is comprised. The solid foam core of the SIP panels also allow for significantly less leaking and drafts. These panels are a cost-effective construction system that saves time and labor while increasing the durability, stability, and quality of your building. SIPs panels can be used as wall, roof, and floor components and they have been proven to be structurally sound, energy efficient, and fire resistant.

Structural Integrity

SIPs are a structural composite with its three components (outer OSB, EPS foam core, and inner OSB) working together instead of against each other for optimal strength. The EPS retains its shape indefinitely and is a key factor in the outstanding durability of the SIPs against time, weather, and other natural impetuses for disintegration.

A Structural Insulated Panel is comparable to a steel I-beam in terms of strength properties. The foam core of the panel acts as a web and the two outside skins function as a flange. The result is a solid building component that has between two and ten times the strength of its conventional stick counterparts, which is especially important in mobile applications like tiny house design. 

Energy Efficiency

The rigid insulation of the foam core allows for less air movement, which means fewer leaks and drafts. This allows the structure to retain the desired temperature (either hot or cold), and gives the HVAC system a reprieve so it does not have to work so hard to maintain the same indoor climate. In the long run, this translates to lower energy bills and less use of non-renewable fossil fuels, all key ingredients in green building design and/or points values for LEEDs, PassivHaus, EarthCraft standards, and other standards and certification systems.

To optimize the efficient, energy-saving edge the SIPs give your building, your HVAC contractor can work in conjunction with the panel manufacturer to provide the best possible heating and cooling system. The use of cutting edge Structural Insulated Panel products and construction practices can eliminate heating and cooling energy demands by 50 to 75 percent more than standard conventional building techniques.

Fire Resistance

The solid core of the SIP panel has a closed cell structure and is built to be airtight. Any fire that comes into contact with the SIP panel will be deprived of the oxygen it needs to burn. Therefore, a fire will not spread through a SIP reinforced wall, floor, or roof as it would with the same structure types filled with fiberglass insulation, which is used for furnace filters because air moves through it so freely. 

Though the panels have been rigorously tested for fire endurance, the foam is still combustible and should not be exposed to flame or other ignition sources if it can be avoided. The fire resistant nature of a structure built of SIPs creates such a tight "outer envelope" that a home with structural insulated panels can actually snuff a fire due to a hungry fire's tendency to consume more air than enters the home. As such, SIP-based houses are expected to survive a fire that would completely destroy a "stick-built" home. 

In any case, properly installed smoke detection, carbon emission detection, and air exchange devices are always recommended.

Wiring SIP Walls

Chases are small tunnels built into the foam core of the panels where electrical components need to be installed. Generally, plumbing is not installed in exterior walls, but plumbing access and vents can be incorporated as well. Chases may be pre-cut into panels during fabrication, or "hot balled" after installation and structural assembly. Your electrical contractor can consult with the panel installer on the methods and procedures that are the most efficient for installing your systems.

Other Benefits

In addition to the benefits you, as a SIPs user, incorporate into your building in terms of structure, energy, and fire resistance, there are also a plethora of other advantages to using SIPs in your home. 

  • SIPs help reduce the intrusion of outside noise
  • SIPs allow for larger windows due to efficiency gains
  • SIPs provide a variety of insulation factors
  • SIPs reduce airborne allergens due to less air intrusion
  • SIPs can be easily sheathed in a variety of styles
  • SIPs simplify complex framing for faster construction
  • SIPs enable open floor plans to be modified over time
  • SIPs are easily altered for exterior additions

The options are wide and varied, and we're glad to discuss options and share thoughts. 

Hybrid Designs

We define a “Hybrid” structure to be a building that is comprised partially of timber frame and partially of SIP-only exterior construction. As a building component, the SIP can also replace traditional stick-framed wall and roof areas for all the same benefits mentioned above.

Contact us to see how the strength, economy, and efficiency of SIPs will work for you and your new cabin, cottage, or tiny house!