SIPs - Structural Insulated Panels

Structural Insulated Panels

Those words define the properties of this innovative building method. SIPs are unique because they combine structure and insulation in one large rigid panel up to 8' x 24'


How they work?:

SIPs share the same structural concept as an I-beam or I-column. The rigid EPS core of the SIP acts as the web, while the OSB sheathing exhibits the same function as the flanges. SIPs combine several components of conventional building, such as studs, rafters or joists, insulation, vapor barrier and air barrier. They can be used for many different applications, such as exterior walls, roofs, and floor systems. The key to this structure's performance is that the EPS foam core keeps the OSB skins from buckling by keeping them "in plane".

One material with two benefits:

The rigid plastic foam core of expanded polystyrene (EPS) is the insulation and the web of the "I" beam. The thicker the panel, the more load the panel will carry and the greater the insulation value.

Superior R-Value

Studies conducted by the Department of Energy's Oak Ridge National Laboratories show that as outside temperatures get colder, the R-value of fiberglass insulation decreases. Using a full scale climate simulator, ORNL tested loose-fill fiberglass attic insulation rated at R-19 at a variety of temperatures. When outside temperatures dipped to -8°F, the R-19 insulation performed at R-9.2. What is more surprising was that infrared imaging revealed convective currents inside the fiberglass insulation. Warm air from inside the house would rise through the insulation, lose heat by coming in contact with the cold attic temperatures, and drop back through the insulation, forming a convective loop of constant energy loss.

In contrast, the rigid foam insulation used in SIPs actually performs better in colder temperatures. Expanded polystyrene with a stated R-value of R 3.9 per inch at 75°F was tested at R-4.2 at per inch at 50°F and R-4.4 per inch at 25°F. More importantly, because all types of SIPs have solid insulation completely enclosed with wood sheathing, they are not subject to any convective currents like fiberglass insulation.

SIPs are an evolution of stick construction

SIPs have evolved as a hybrid of stick-built construction and use dimensional lumber for corner connections, plates and window/door framing point loads, and sub-fascia. SIPs are sized to work with standard dimensional lumber; 2 x 4, 2 x 6, 2 x 8, 2 x 10 and 2 x 12. Compared with stick framing, construction with SIPs eliminates many steps and time is saved. SIPs contain the "framing", sheathing, and insulation in a product that is assembled in one step

A 4 kW solar installation can generate 73% of an average household’s electricity needs, therefore, preventing 135 tons of CO2 from entering the environment. This is equivalent to planting 5,600 trees since each tree absorbs approximately 48 lbs of CO2. Carbon Dioxide creates global warming which is dramatically affecting our climate causing glacier loss, shoreline erosion, and endangering many animals around the world.

Structural Insulated Panels:

SIPs are a unique building product because they combine structure and insulation in one large rigid panel – available in many thicknesses and sizes, up to 8' x 24'

Nail Base Panels:

NetSolar SIPs offers a nail base panel to be used in roofing and siding applications requiring OSB on one side of the panel only. This provides excellent insulation, and a nail base for attachment of roofing and siding.

Standard Thicknesses: (Nominal: Actual)

  • 4-1/2" 4-5/8" (3-3/4"EPS core+ (2) 7/16" OSB skins)
  • 6-1/2" 6-5/8" (5-3/4"EPS core+ (2) 7/16" OSB skins)
  • 8-1/4" 8-3/8" (7-1/2"EPS core+ (2) 7/16" OSB skins)
  • 10-1/4" 10-3/8" (9-1/2"EPS core+ (2) 7/16" OSB skins)
  • 12-1/4" 12-3/8" (11-1/2"EPS core+ (2) 7/16" OSB skins)
Note: Custom thicknesses are available

Long Term Savings and Resale Value

In the long term, SIP structures are less expensive to operate due to the superior insulation value of SIP panels. SIP panel construction is typically Energy Star rated. An energy savings of over 50% can be expected. What this translates to in dollars depends on the cost of energy at the structure's location, but in most of New Mexico it amounts to $1,200 per year or more. Additionally, better thermal efficiency translates into higher resale value. A study by ICF Consulting funded by the Environmental Protection Agency revealed that energy efficiency increases the resale value of homes by $20 for every $1 in annual energy cost savings, or about $20,000 for the average SIP house.

Tax credits for SIPs

In 2005, The United States Energy Policy Act was signed into motion by President George W. Bush. This legislation allows for financial incentives for those building energy efficient structures. By using NetSolar SIPs builders and contractors can qualify for a $2000 tax credit on a residential home or up to $1.80 per square foot tax deduction on a commercial building.

Residential contractors are eligible for a $2000 tax credit provided the new energy efficient home achieves 50% energy savings as dictated in the International Energy Conservation Code (IECC). Accordingly, at least one fifth of the energy savings must occur from air tightness and through R-value rating on insulation. SIPs are an ideal candidate for these gauges because of their superior thermal performance.

Builders can qualify for a $1.80 per square tax credit if the new or existing commercial buildings demonstrate at least 50% energy efficiency in the areas of heating, cooling, water heating, and interior energy cost as mandated by ASHRAE Standard 90.1-2001. Partial tax credits are also available to builders meeting several but not all of the criteria. In order to qualify for the $2000 residential tax credit, builders must follow the guidelines dictated on IRS Notice 2006-27.

The Internal Revenue Service has created IRS Form 8908 to assist builders with the tax credit application process.

Contractors for commercial buildings must adhere to procedures listed in IRS Notice 2006-52 in order to qualify for $1.60 per square foot tax credits.

Other Construction Savings

Aside from the direct constructions costs, there are other immediate cost considerations that are more difficult to quantify, but that are nonetheless quite real.

  • Smaller Furnace:

    A SIP home tends to be 50% to 75% more energy efficient than conventional counterparts. The heating and air conditioning system for a SIP home may also be correspondingly smaller and, therefore, less expensive.

  • Shorter Ductwork:

    The air duct system can be considerably shorter. The old duct rule of running all registers to an exterior wall of each room was intended to counter the inevitable air infiltration along the rim of the house common with conventional walls. This rule does not apply to a SIP building. Registers may be run to the closest wall of each room, at considerable savings. In fact, houses designed to optimize savings from SIP construction usually use a central utility pod design that further minimizes utility runs of all kinds.

  • Less Loan Interest:

    Using factory precut wall and roof panels, a SIP built house can be installed in days instead of weeks. If you are building under a construction loan, expect to save between 2 and 4 weeks worth of interest.

  • Cheaper Interior Finishing:

    Directly under the interior drywall of a SIP wall is a solid layer of OSB. Drywall, trim and cabinet installation time are greatly reduced, callbacks due to popped drywall nails and screws are virtually eliminated and the drywall is absolutely straight and flat. There is less drywall waste and fewer seams because drywall does not have to be trimmed to terminate exactly on a stud.

  • Less Job-Site Waste:

    Factory precut SIPs eliminates most job waste due to wall framing and therefore reduce waste management cost and landfill fees.

  • Cheaper Electrical Installation:

    Electrical installations take less time. The pre-installed wire chases in SIP panels eliminate the need to drill studs for electrical wiring.

  • Fewer Callbacks:

    No bowed studs. Not only straighter, truer walls, but no return trips to straighten bowed studs before the drywall goes on.