“SIPs and IMPs” may sound like a silly kid’s game, but structural insulated panels (SIPs) and insulated metal panels (IMPs) are far from child’s play when it comes to construction as they are popular building materials used to insulate structures.

While they may sound the same, SIPs and IMPs have some key differences.

“SIPs are not to be confused with insulated metal panels (IMPs). While similar in their composition and installation, they are not the same,” says Metal Construction News.

SIPs vs. IMPs: Tale of the Tape

Structural Insulated Panels (SIPs), according to the Structural Insulated Panel Association, are high-performance building panels used in floors, walls, and roofs for residential and light commercial buildings. The panels are made by sandwiching a core of rigid foam plastic insulation between two structural facings, such as an oriented strand board (OSB).

Insulated Metal Panels (IMPs), according to the Metal Construction Association, are lightweight composite exterior wall and roof panels with metal skins and an insulating foam core. These panels have superior insulating properties, and their outstanding spanning capabilities and one-pass installation make them quick to install, saving costs compared to other wall assemblies.

SIPs provide an effective insulation barrier and function as structural elements, helping to support the weight of the building. They are often used in residential construction and are known for their energy efficiency.

IMPs are typically used as exterior cladding and roofing systems but can also be used as interior partition walls They are often used in industrial, commercial, and institutional buildings.

SIPs are known for:

• Exceptional thermal performance
• Healthier indoor air quality
• Sustainability credentials
• Faster construction with less labor
• Creative design
• Residential construction

IMPs are known for:

• Superior insulation qualities
• Spanning capabilities
• One-pass installation
• Durability
• Fire resistance
• Ability to withstand high winds and other weather events
• Architectural and aesthetic elements
• Cold storage market and other industrial, commercial, and institutional applications

More About Structural Insulated Panels (SIPs)

SIPs were first introduced in 1935 by the Forest Products Laboratory in Madison, Wisconsin and famed architect Frank Lloyd Wright used a form of SIPs in the Usonian homes he built in the 1930s and 1940s.

Despite their longevity, SIPs are still relevant in building today.

“Today, SIPs are prefabricated building components for use as walls, floors, roofs, and foundations. SIPs provide a continuous air and vapor barrier as well as an increased R-value when compared to traditional construction. Construction costs associated with SIPs are comparable to more conventional building methods when savings associated with labor costs, material waste, and energy efficiency are considered,” says the Whole Building Design Guide.

Their energy efficiency has put SIPs in the spotlight as sustainability issues take front and center in construction.

“Today's architects are faced with the urgent task of achieving energy-efficient and high-performance building enclosures. Structural Insulated Panels are an option for part of the enclosure assembly that can help achieve these goals,” says the Whole Building Design Guide.

While oriented strand boards (OSBs) are the most common sheathing boards used in SIPs, other materials used include:

• Sheet metal
• Plywood
• Fiber cement siding
• Magnesium board
• Fiberglass mat gypsum sheathing
• Composite structural siding panels

Typical SIPs cores, with benefits, include:

• Expanded Polystyrene (EPS): Least expensive; thickness options are only limited by the foam manufacturer; availability; fastest to modify in the field; most benign blowing agent.
• Extruded Polystyrene (XPS): Strength; water resistant.
• Polyurethane Foam (PUR): Highest R-value/inch; strength; water resistant.

The R-value/inch at 75 degrees Fahrenheit are:

• EPS: 3.6
• XPS: 5.0
• PUR: 6.54

More About Insulated Metal Panels (IMPs)

Insulated Metal Panels (IMPs) are newer than their forerunner SIPs, first coming to market in the 1960s, but have gained in popularity over the last decade as advancements in manufacturing and technology are made.

“IMP technology’s time has finally come as growing numbers of building owners and developers are demanding greater value and higher energy efficiency, and they are not willing to sacrifice aesthetics,” says Metal Architecture. “Designed to create a protective barrier against water, air, vapor, heat, and cold, IMPs deliver energy efficiency resulting in lower heating and cooling costs. With growing frequency, they are being used in the construction of cold-storage facilities, aircraft hangers, manufacturing plants, office buildings, convention centers, and more.”

Metal Architecture Academy says that IMPs gain their high-performance insulation by having foam injected between two metal sheets where it undergoes a chemical reaction, causing it to rise and bond to the metal skins, thereby filling the interior cavity.

“The result is a solid monolithic panel that maintains a consistent thermal value and also resists moisture, insect, and rodent infiltration,” says the Metal Architecture Academy.

The most commonly used metal substrate for IMP faces are G90 galvanized steel or aluminum-zinc coated steel, while some custom panels are made from stainless steel or aluminum.

IMPs have morphed from their one-note origins of the 1960s to today’s array of design options including:

• Flat and profile panels
• Color
• Texture
• Panel width
• Joint size option
• Joint orientations

“IMPs can also be curved and formed, and come in a variety of high-performance coatings,” says the Metal Architecture Academy.

IMPs are very popular in the cold storage industry, with a typical nominal R-value of R-8 per inch, and can be found in other types of buildings including:

• Education
• Government
• Healthcare facilities
• Hospitality
• Offices/banks
• Manufacturing
• Recreation
• Transportation
• Warehouses

“Based on their inarguable diversity and recent gain in popularity it seems prudent to embrace IMPs exactly for what they are: a beautifully strong and thermally efficient metal cladding product,” says Green Span Profiles Vice President Brian Jaks. “Not unlike the standing seam roof before it, most believe IMPs will revolutionize certain sectors of the construction industry. They are readily available, easy to install, and day after day designers seem to find new and exciting applications for this dynamic and versatile building product.”

Contact Green Span Profiles today to learn more about how insulated metal panel technologies can help your next building project.