Technical & Installation FAQs
How much does a SIP weigh?
A 4 x 8 x 4½” SIP weighs about 100 lbs.
Are the panels structural?
Yes. And tests indicate Thermapan SIPs are significantly stronger than conventional 2×4 or 2×6 walls.In fact, houses built with Thermapan SIPs have withstood the force of Class 6 hurricanes, such as Andrew, Hugo and Mitch.
What is the R-Value of a SIP?
The real-time R-Value of a SIP depends on its thickness and environmental factors.
Isn’t there still thermal bridging at point load columns in a SIP wall?
Point loads constructed from lumber are not a true thermal bridge. Wood is a decent insulator, albeit not nearly as good as the insulation used in SIPs. As a whole, SIP walls far exceed building code effective R-Value requirements, even after accounting for point loads.
Building code packages that call for a layer of continuous insulation on the exterior of traditional stud & batt framing are designed in order to reduce the possibility of a dew point (condensation) forming inside the wall cavity – which can lead to mould growth. This won’t happen with SIP systems, because there is no wall cavity and the layer of EPS insulation is closed-cell, i.e. rigid.
Consider that R-19 + “5 ci” nominal code standard (OBC Package A-2) translates to an effective R-20.32. 4.5” SIPs deliver an effective R-22.7, as a single component, with much enhanced air-tightness among many other benefits.
Do SIPs come pre-framed with windows and doors?
No. Thermapan SIPs use a standard system that makes them easy to assemble and extremely cost effective. One of the key benefits of the Thermapan system is its design flexibility. SIPs can work with any number of window and door combinations. Thermapan’s reference manual also makes the installation of windows and doors straightforward and simple. View the Door & Window Openings segment of our Installation Video and see how easy it really is.
What tools do I need to install SIPs?
You will need regular carpentry tools plus a hot knife and expanding foam. A hot knife is a tool for holing out grooves in the EPS, and is needed whenever SIPs must be cut to size. Hot knives are easy to use and can be purchased or rented from Thermapan. Expanding foam is used to seal all connections between individual SIPs and top and bottom plates thus ensuring the structural integrity of the system. For a full list of SIP tools that Thermapan can supply, visit our Accessories page.
How do you install electrical?
Thermapan SIPs are both simple and easy for electricians to wire. Visit our Installation Photos page for some detailed shots of electrical installation and to watch our Electrical Installation Movie.
What is the fire rating of a SIP?
With 1/2″ gypsum board, SIPs have a 15-minute fire rating which meet residential fire code regulations. Thermapan SIPs also meet the National Building Code of Canada. As with any fire resistance issue, however, requirements vary by region, occupancy and building classification. You should contact your local building or fire departments to determine the necessary requirements and ensure compliance with local fire codes.
Do SIPs contain formaldehyde?
The answer to this question is while technically yes, effectively they do not. This is because the amount of formaldehyde emitted by the oriented strand board (OSB) used in SIPs is less than 0.1 PPM (parts per million). This is well below accepted levels established by the U.S. Department of Housing and Urban Development (HUD). Additional details and test results can be found in this Technical Document.
Product FAQs
What is a Structural Insulated Panel (SIP)?
A Structural Insulated Panel (SIP) is a high-performance building panel made of an insulating foam core bonded between two structural facings. SIPs provide insulation and structural support in one system, reducing air leakage and improving energy efficiency compared to traditional stick-built construction.
How do Thermapan SIPs improve energy efficiency?
Thermapan SIPs create a continuous insulated building envelope that minimizes thermal bridging and air leakage. Moreover, the closed-cell nature of EPS insulation reduces the potential for heat loss through air infiltration. All this helps maintain consistent indoor temperatures, reduces heating and cooling demand, and lowers long-term energy costs.
Are Thermapan SIPs suitable for cold and extreme climates?
Yes. Thermapan SIPs have been successfully used in some of the world’s most demanding climates, including Canada and the Arctic Circle. Their airtight construction and high insulation values make them well suited for cold, hot, and variable weather conditions.
Can Thermapan SIPs be used for residential and commercial buildings?
Thermapan SIPs are designed for both residential and commercial construction. They can be used for exterior walls, roofs, floors, foundations, additions, timber-frame structures, and log homes.
Are SIP panels stronger than traditional wood framing?
SIP panels distribute loads across the entire panel surface rather than through individual studs. This creates a strong structural assembly capable of supporting roof and wall loads while improving overall building rigidity.
Do SIP homes reduce construction time?
Yes. Because SIP panels combine structure, insulation, air barrier, and vapour barrier properties, there are fewer construction stages involved, allowing builders to assemble the building envelope faster than traditional framing methods.
What insulation is used in Thermapan SIP panels?
Thermapan SIP panels use expanded polystyrene (EPS) insulation bonded between structural facings to create a durable, high-performance building panel.
Are SIP panels good for energy-efficient homes?
Yes. SIP construction is widely used in high-performance builds, including Net-Zero homes, because the continuous insulation and airtight envelope significantly reduce overall heating and cooling demand.