SIPs 101 | Structural Insulated Panels Unwrapped

Graphite polystyrene structural insulated wall panels stacked on the a job site as part of a timber frame home kit.

Panelized homes are becoming the norm in the US and around the world. SIPs, or Structural Insulated Panels, are at the forefront of the movement as the most efficient, sustainable, and cost-effective solution to residential construction.

If you’re new to SIPs and want to learn more about their composition, how they are used in residential construction, and the ease of assembly… you’ve come to the right place. Join in as we unwrap the world of panelized construction using SIPS.

Table of Contents

What is a SIP (Structural Insulated Panel), and How Do They Work?

Structural Insulated Panels (SIPs) are prefabricated wall and roof panels composed of lightweight, closed-cell foam insulation sandwiched between structural grade OSB facings.

Check out the diagram below to get a better visual understanding of the internal and external components of a SIP.

SIP Wall Anatomy

How Do They Work?

The assembly of a panelized structure is incredibly efficient. Each individual panel is precision cut and labeled in a factory under controlled conditions, then shipped to the job site. The panels arrive as 4’x8′ or 8’x24′ sections ready to be lifted into place.

In the brief video from the Structural Insulated Panel Association below, you can see how each panel is set into place, creating the home’s exterior shell.

When paired with a timber frame kit, SIPs wrap around the timber elements to enclose the structure. The timbers then carry most of the load from the roof, while the SIPs act as a strong, air-tight insulating shell. Reference the image below to see how SIPs and Timbers work together to create a stunning and structurally sound home.

construction plans showing structural insulated panels placed around a timber frame cabin design
SIPs Plans For a Timber Framed Cabin Kit

Advantages of Building with SIPs

SIPs have been around for over half of a century, but they seem just now to be receiving the attention they deserve by builders and homeowners worldwide. Let’s take a closer look at a few of the reasons why SIPs have become the go-to wall and roof system.

SIPs Provide Uncompromised Energy Efficiency

The primary benefit that comes to mind for most people when they think of building with SIPs is energy efficiency. That’s because SIPs provide a two-part solution to the inefficiencies associated with conventional 2x framing.

First, SIP wall panels utilize a closed-cell foam core instead of spray foam, blanket, or loose-fill insulation. Closed-cell foam insulation is a far superior insulator to the alternatives. Blanket-style insulation typically has an R-Value of 2.9 to 3.8 for every inch of thickness. The foam used in SIPs has an R-Value of R-4 to R-6.5 per inch of thickness.

What separates the closed-cell foam used in SIPs apart from spray foam is the concept of thermal bridging. A thermal bridge is an area or component of an object (in this case, the 2×4 or 2×6 stud) which has higher thermal conductivity than the surrounding objects, creating a path of least resistance for heat transfer. SIP walls practically eliminate the need for 2x framing in the exterior walls, resulting in fewer thermal bridges than a conventionally framed alternative.

Next, SIPs provide a nearly air-tight structural shell which helps to minimize air transfer from outdoors in, and vice versa. This reduces the fluctuation in indoor air temperature and humidity, which allows your HVAC system to run effortlessly at a low monthly cost. Overall, the closed-cell insulation paired with air-tight construction results in buildings with remarkably low energy consumption.

SIPs Streamline Construction Timelines

SIP wall and roof panels are dramatically faster to erect than conventional stick-built construction. This can mean a lot to builders and homeowners because it is one of the most labor-intensive parts of building a home. Ultimately, SIP wall panels allow you to enclose your home, get it dried in, and get on with your interior finish work in a shorter period of time.

Prior to the SIPs arriving on the job site, they are pre-cut with precision accuracy. Therefore, when they arrive on the lot, they can be lifted into place, reducing the redundancy of the measure twice, cut once, style of stick-built construction. This saves a considerable amount of time and ensures perfection throughout the process, especially when compared to conventional construction, where materials are measured and hand-cut on site.

Another streamlined benefit associated with the use of SIPs is electrical work. SIPs include pre-built electrical chases at 17.5″ and 44″ off the bottom of the panel. This dramatically reduces the time it takes an electrician to rough in the basic wiring of your home. All in all, providing a more streamlined new construction process.

SIPs Help Save You Money

SIPs can help builders and homeowners significantly reduce their labor costs. If you have ever had to build with traditional materials, you know that there is an incredible amount of time spent cutting and arranging pieces to fit together to match the plans. This is not necessary with SIPs. In fact, it is possible to frame an entire home in just a matter of days because SIP panels are already cut, measured, and test fit at the factory.

As the skilled labor shortage continues to grow in the US, labor is quickly becoming one of the most scarce resources in the construction industry. Traditional building practices are bogging down the depleted workforce, and construction timelines are being extended due to global supply chain issues. This has put prospective homeowners interested in new construction in a tough place.

Builders can thwart both issues by switching to SIPs construction. First, the ease of installation is less labor demanding, allowing smaller screws to work with greater efficiencies. Second, when you build with SIPs, you are no longer at the mercy of your local lumberyard and the supply chain issues they are facing. You know that when you place an order through a reputable manufacturer, you will receive a prefabricated wall system on-site, on time, and for the price you’ve committed to often months prior.

Another unique attribute of a SIPs home is the lifetime cost savings associated with the structure’s energy efficiency. SIP homes are constructed to be air-tight and energy-efficient (see energy efficiency above). As a result, homeowners who build with SIPs see cost savings of up to 60% on heating and cooling compared to a traditionally built home.

SIPs Provide Superior Strength

One question we get daily is if we can build a SIPs home in “so and so” location because of either high wind loads, snow loads, or seismic loads. The answer is almost always YES!

Structural insulated wall and roof panels carry nearly double the vertical and horizontal load of a traditional 2x framed wall system. A panelized home can be constructed nearly everywhere where stick-framed construction is up to par while providing extra benefits for individuals building in locations with severe load requirements.

Another added benefit that correlates with the strength of SIPs is the flexibility of design. When framing a home with standard 2x lumber, you’ll often need to over-engineer in certain places to arrive at the design you desire. The sheer strength of SIPs allows for more freedom in design without adding any extra material.

SIP Walls Provide Soundproofing

Expanded polystyrene (EPS) foam core SIPs are incredible for soundproofing. The EPS foam has absorption and decoupling characteristics that, when paired with an OSB sheathing, help to muffle and reduce sound transfer between walls. Loose-fill and blanket-style insulation have no decoupling characteristics, allowing for considerable sound transfer and vibration.

Most SIP homes are constructed using a panelized system on the exterior and standard 2x framing on the interior. It is essential to understand that SIPs can also be used as interior walls. It is especially nice to utilize the soundproofing nature of the SIP interior wall systems when designing a home office, movie room, or personal studio.

SIPs Help Prevent Insect & Rodent Infestations

Not all SIPs are created equal, but when you work with a reputable manufacturer, you can expect a product that is not only structurally sound and well-insulated but also rodent and insect resistant.

Extreme Panel Technologies, an industry leader in SIP manufacturing, employs a zinc borate treatment in its manufacturing process. Zinc borate helps protect the OSB sheathing of the wall and roof panels from biological elements such as fungal decay and thwarts the impact of insect damage. The treatment is also non-toxic and safe for humans, pets, and the environment.

For more information on Extreme Panels Structure Shield zinc oxide treatment, check out their in-depth product brochure.

How to Install SIP Panels – Understanding SIP Construction

Now that you have a basic understanding of what SIPs are, how they work, and the types of benefits that they provide the everyday homeowner or builder, we can dive deeper into the technicalities of the panels.

Join our panel manufacturer, Extreme Panel Technologies, as they walk you through an 18-part video series detailing the installation of SIPs. By the end of the series, you’ll have a thorough understanding of how a SIPs home is constructed and can choose whether or not it’s the right choice for your project!

18 Part Video Series – From Foundation to Electrical

Extreme Panel Introduction

Understanding What’s Included in Your SIP Panel Package

How to Read SIP Panel Construction Drawings

How to Install SIP Bottom Plates

How to Install SIP Wall Panels

How to Install Box Splines in SIP Wall Panels

How to Install Corner Lumber in SIP Panels

How to Install Top Plates in SIP Panels

How to Install Top Shim Plates in SIP Panels

How to Install Window Buckling in SIP Panels

How to Install Panel Tape on a SIP Wall Panel

How to Fasten Stick Framed Interior Walls to SIP Exterior Walls

How to Install SIP Roof Panels

How to Install and Seal Tail Pocket Material in SIP Roof Panels

How to Install SIP Panel Tape on a Ridgebeam

How to Seal the Ridge of A SIP Roof Panel

How to Wire a SIP Panel – Tips and Tricks

The Mechanical Advantage of Using SIPs

Want to learn more?

You can reach out to the staff at Integrity Timber Frame with any questions, comments, or consultation requests by filling out our brief contact form, sending us an email at [email protected], or giving us a call directly at (888)731-4299.

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