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Solid Core / SIP Panels

  What is Solid Core or SIP Construction?

    Structural Insulated Panels join high performance rigid foam insulation to Oriented Strand Board (OSB) or plywood. The thickness of foam is adjusted to increase R-Value. Exterior and interior facings are shown with standard OSB. Drywall is field applied as needed. The first Solid Core type construction was made in 1935 and the buildings are still in use today, nearly 70 years later.

    Every EPS Solid Core package includes pre-assembled, insulated headers, along with window and door cutouts and horizontal and vertical electrical chases. Using EPS solid core roof panels, a home can have high vaulted ceilings.

New EPS Home Construction
SIPs Save the Environment
  • Efficient use of wood for skins
  • Reduced Dust, Moisture and Noise
  • Eco-friendly product
  • Qualify for various green building programs
New EPS Home Construction
SIPs Save Labor
  • Eliminate call backs
  • Straight, flat, true walls
  • No drywall nail pops
  • No cracks due to lumber shrinkage
  • Interior framing can be done after SIPs are set
New EPS Home Construction
SIPs Save Time
  • Faster dry-in time
  • Less material sorting
  • Allow subcontractors access sooner
  • Less waste
  • Less bracing required
New EPS Home Construction
SIPs Save Money
  • Less jobsite waste
  • Reduced HVAC equipment cost
  • Shorter duct runs
  • Increase of appraisal value
  • Earn energy efficiency tax credits
  • Save on construction financing
New EPS Home Construction
SIPs Save
  • Up to 50% more energy efficient when combined with other energy efficient technologies
  • Create a tighter building, up to 15 times more air-tight
  • Reduce size of HVAC equipment
  • Whole-wall R-value outperforms fiberglass insulation

Solid Core Buildings

Our solid core panel structures are versatile. We'll help design the best possible solution to fit your needs. EPS and Mid Missouri Pole Buildings can provide combination post-frame storage and Solid Core Panel walls in any of our buildings, to enhance insulation and performance.

Structural Insulated Panels join high performance rigid foam insulation to Oriented Strand Board (OSB) or plywood. The thickness of foam is adjusted to increase R-Value. 

Energy savings is measured in whole wall R-Value, not just insulation values. Our 6-inch core walls outperform standard steel or stick built walls by over 50%.

Interior wall temperatures are much improved over stick or steel walls. Solid core walls have no sagging insulation, no compressed insulation, no air movement, only solid cores. With no thermal shortcuts to external walls, they simply translate to large savings on your utility bills. The results speak for themselves. Our core panel system is 15 times better at stopping air infiltration. This offers you a comfortable building by virtually eliminating drafts.

Solid Core Ag BuildingChoose from the standard R-18, R-26, R-33 or R-40 walls. The colder the outside temperature--the better the R-Value. All types of buildings can be engineered in just about any dimension.

EPS and Mid Missouri Buildings panel systems offer complete customization of roof materials. The most popular are trusses with purlins or structural insulated panels over the top of trusses which offer open attic designs. Shingles, standing seam roofs or virtually any roofing material can also be used.

As with the roofing, siding options are also limitless. Brick, vinyl, cement board siding or just about any material is easily attached to our core panel surface.
Proven Stronger:
Impact resistance is another standard feature of structural insulated panels. The continuous bonding of EPS insulation to the OSB or plywood offers incredible strength and resistance to impact.

Vertical and horizontal stress loads are tested two times stronger than conventional stud walls. EPS walls resist up to 7,000 pounds per foot which results in structures that are stronger, straighter, taller and wider.

EPS buildings are engineered with IBC codes to your wind and snow loads and can be stamped in 50 states. EPS has state-of-the-art production facilities and five truss lines to give you cost-effective solutions.

     Conventional Framed Walls (CFW)  
                                                    Compared to  
                                  EPS Structural Insulated Panels (SIP)

Wall System Description

 CFW: 2x6 wall framed at 16” o.c. installed with R-19 fiberglass insulation.

SIP: Structural insulated panels (SIPs) are high performance building panels used in floors, walls, and roofs for residential and light commercial buildings. The panels are typically made by sandwiching a core of closed-cell rigid foam plastic insulation between two structural skins of oriented strand board (OSB). Depending on the size and needs of the structure, the thickness of the foam is adjusted to increase R-value.

R-Value Performance

  R-Value of 13.7

SIP: R-Value of 24.7. Depending on the size and needs of the structure, the thickness of the
foam is adjusted to increase R-value.

Thermal Breaks

CFW:   Each stud location represents a thermal short circuit in the insulating barrier, allowing moisture-filled air to pass. When wood 2x6 framing is used, an average 33% of the wall surface is comprised of 2x6 framing that is R-6.

SIP: EPS SIPs join high performance closed-cell rigid foam insulation to oriented strand board (OSB) or plywood. It averages only 7% of the lumber used in the shell of a building.

Moisture Effect on R-Value

CFW:  Fiberglass can lose as much as 80% of its R-value when exposed to even low moisture levels, which are common below grade. Moisture leads to wood decay.

SIP:  When exposed to moisture, the R-value SIPs remains constant and will shed liquid water.

Temperature Effect

CFW:  Fiberglass insulation loses as much as 40% of its insulating capacity when temperatures fall below 20˚F and over half its R-value below 0˚F.

SIP:  The thermal performance of SIPs are not affected by changes in temperature. In fact,studies have shown R-values to improve as temperatures decrease.

Compression Effect  

CFW:  Fiberglass must be fully expanded to work properly. If it is stuffed into openings or compressed by plumbing or electrical wires, it loses most of its R-value.

SIP: Electrical wire chases are internal in an EPS panel system.

Mold and Mildew  

CFW:  Organic wood studs absorb moisture and support mold growth. Fiberglass insulation also absorbs moisture and promotes mold growth.

SIP:  An airtight SIP building envelope forms the basis of a successful mold control strategy. The extremely low levels of air infiltration in SIP buildings allow for incoming air to be provided in controlled amounts by air handling equipment. Proper dehumidification of incoming air following ASHRAE standards will create an environment where mold physically cannot grow. In addition to creating an airtight structure, SIPs are solid and free of any cavities in the wall where moisture can condense and cause unseen mold growth.

Indoor Air Quality  

CFW:  Wood building materials and fiberglass insulation are often treated with preservatives and formaldyhyde. Mold and airborne toxins contaminate the indoor air quality.

SIP:  The tightness of the SIP building envelope prevents air from gaining access to the interior of the home except in controlled amounts. A controlled indoor environment is both healthy and comfortable. Humidity can be controlled more easily in a SIP home resulting in a home that is more comfortable for occupants and less prone to mold growth and dust mites. SIP panels have no offgassing and use no formaldahyde. 

Strength & Stability 

CFW:  Wood frame construction exceeds strength requirements but degrades over time. Wood framing members warp and twist as moisture levels vary. Nail “pops” are common.

SIP:  The structural characteristics of SIPs are similar to that of a steel I-Beam. The OSB skins act as the flange of the I-beam, while the rigid foam core provides the web. This design gives SIPs an advantage at handling in plane compressive loads. SIPs can be engineered for most applications.

 Vapor Control

CFW:  Basement walls must be able to dry. For walls built below grade, drying typically means towards the interior. Adding vapor barriers to control the moisture actually keeps the moisture from being able to dry properly. If placed directly against the masonry wall, an impermeable barrier keeps moisture from being able to dry towards the interior. If installed over the wood frame moisture is trapped inside the wall cavity causing wood to rot and mold to grow.

SIP:  Air barriers or vapor barriers are not required in SIP buildings because properly sealed SIPs create a code compliant air barrier with a permeability rating of less than 1.0 perm. In addition, the foam core of SIPs is solid and continuous throughout the wall, eliminating the convection and condensation issues that can occur in cavity walls above and below grade.

Installing Insulation

CFW:  The performance of the thermal barrier is dependent in part upon the quality of workmanship. For fiberglass insulation to work effectively, it must be in continuous contact with its surrounding surfaces on all six sides. It is virtually impossible for installers to achieve this on a job site. Even the smallest gap allows air circulation which kills the insulation value.

SIP:  Because SIPs are prefabricated, the amount of additional framing required is minimal. SIPs are always straight and true, there are far fewer callbacks, no culling studs, or need to straighten walls. SIPs also provide a uniform nailing surface for both interior and exterior finishing.

Environmental Impact

CFW:  Wood framing members are produced from trees and treated with preservatives. Fiberglass insulation is often produced with formaldahyde.

SIP:  Since SIPs are prefabricated in the factory, there is less jobsite waste that needs to be landfilled. Factory fabrication is done using optimization software EPS recycles factory scrap to make other foam products. Structural insulated panels are one of the most environmentally responsible building systems available. A SIP building envelope provides high levels of insulation and is extremely airtight, meaning the amount of energy used to heat and cool a home can be cut by up to 50 percent.


CFW:  Wood frame walls attract moisture, mold, and insects which eventually leads to wood rot and deterioration. When realworld factors such as air infiltration, extreme temperatures and thermal bridging are present, field-installed fiberglass insulation can lose more than half its R-value.

SIP:  Research has repeatedly shown that SIPs provide continuous insulation that will maintain its stated R-value for the life of the home and outperform fiberglass insulation every time.

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