Structural Insulated Panels (SIP) are a great high performance framing product to build the thermal shell of a home and have gained popularity throughout the world because of their superior characteristics. SIPs have some competition in other types of wall systems like Insulated Concrete Forms (ICF) with their biggest competition being conventionally framed homes with dimensional lumber. With respect to competitive wall systems, SIP can offer an efficient integration with the roof design to provide a complete thermal solution. For our region there are some really good reasons to consider SIP for your next construction project.
In hot humid climates like Central Texas it is important to have a sealed building envelope, so good insulation and keeping moisture out are big hot buttons. Travis Santi, the Design Supervisor of EH Systems in New Braunfels, Texas shared some advantages of SIPs over conventionally framed homes in 3 main categories; Energy Efficiency, Structural Integrity, and Time Savings.
Energy Efficiency
– SIPs have 13 times less air infiltration than conventional stick framing and batt insulation, according to an Oakridge National Labs study of a SIP house vs. an identically designed stick house.
– Air infiltration is drastically reduced compared to batt insulation because of the solid EPS core of insulation in the wall cavity, and expanding foam sealer used at all connections. Once you factor in thermal bridging from wood studs and leaks from no air barrier, you start to wonder why we haven’t converted to SIP earlier.
– The whole wall R-value of 4 ½” SIP wall is R-14, compared to the whole wall R-value of a 2×6 conventionally framed wall of R-11-13, depending on the attention to detail of framing and insulation.
– Your A/C system load design will be reduced substantially – up to 50% of what is needed for the conventionally framed home. With this savings, purchase an ERV and/or dehumidifier to pretreat the air. The indoor air quality will be significantly better because the incoming air is filtered and preconditioned by the equipment.
Structural Integrity
– SIP have superior strength, they can span farther, soar higher, and support more load than conventionally framed walls and roof systems. The in-plane shear strength of a SIP wall is 380 PLF which is twice that of a stick framed wall with wind bracing. An 8’ tall SIP wall 4 ½” thick can support 3,700 PLF of axial load. Also, an 8 ¼” roof panel with average load can span 16’, while the 10 ¼” roof panel can span 18’ horizontally.
– The uniformly spread load of SIP shell eliminates the need for window and door headers up to a 10’ wide opening in most cases.
– SIP are more resistant to mold, mildew, and fire than stick framing.
– SIP are very durable and long lasting through quality control of the lamination process.
Time Savings
– The framing, sheathing, caulking, air barrier and insulation are done in one step greatly reducing construction time and the number of trades on the jobsite.
– The walls and roof systems are pre engineered and pre-cut, so there is a 45-55% savings in time as compared to conventional framing, according to RSMeans Estimating. The framers put the pieces together like a big puzzle with instructions.
– SIP are installed with normal wood framing tools and special screws and foams are supplied by the manufacturer. The only additional cutting that is necessary is for the plates which are also supplied by the manufacturer.
– SIP reduce jobsite waste because all the panels come precut from the manufacturer.
EH Systems is the highest quality manufacturer of SIPs in Texas. EHS has their own nationally recognized code report and SIPs have also been incorporated into the 2006 IRC in section R614. EHS is also 1 of 2 companies in the country with a TDI report; Texas Department of Insurance criteria for use in designated catastrophe areas along the Texas Gulf Coast. They are the only SIP manufacturer in Texas with these credentials.
EHS will assign a builder service representative for your job to do onsite training and advisory. EHS has a 10 year warranty on materials. Typically, there is a cost premium on SIP, but as energy costs keep increasing, your return on investment time decrease. Current return on investment times is 2-4 years through reduced energy bills, not to mention all the other benefits you will enjoy in the mean time.
Travis says that since SIP are sold by the square footage of surface area, the design is critical in order to add value. Your home can be designed in a SIP friendly way to increase the material efficiency of the SIP package. This can affect the costs for your SIP package by up to 40%. By keeping your roof simple and maximizing panel sizes, spans, plate heights your total cost can be competitive with stick framing and much less than ICF.
Travis would like to refer contact to Allen Scarborough at EHS who can provide estimates and value engineering of your design. He can be contacted at 210-287-2205, ascarborough@ehsystemsllc.com