How one builder uses special materials to build more affordable, sustainable houses around Charlotte
I recently noticed a new house being built with strange looking materials at the end of my street in NoDa. It looked like plywood with thick foam between the boards.
I was intrigued and did a bit of investigating. The material is called Structural Insulated Panel System, or SIPs, as they are called in the building industry. Simply explained, insulated foam is sandwiched between two oriented strand boards. According to the Structural Insulated Panel Association website, this type of building system is strong, energy efficient and cost effective.
I tracked down the builder, Thomas Cox with Gastonia-based Green Apple House, to find out more about SIPs and the reason why he was using this material.
Why do you use SIPs?
“SIPs make sense as they are the perfect combination of structural efficiency combined with energy efficiency. The ‘structural panel’ builds walls and provides enhanced energy efficiency by combining insulation within a wall and roof panel. When accurately measured, SIPs provide 2-3 times the insulating value of fiberglass batts stuck into wall framing.”
What is your experience with SIPs?
“I’ve built with SIPs for 30 years and worked all over the country.”
What else is different about the way you build?
“Green Apple House uses SIPs and engineered lumber in a format I call ‘modulus efficiency.’ The basis of this is that materials are used, whenever possible, in their full form to avoid waste.”
What is the price difference in building a house like this?
“The cost differences are dependent on the efficiency of the design and framer. I can build with SIPs and timber for much the same cost as stick framing. A house like the one in NoDa can be built in the $120 square foot range, and I have plans to reduce that cost with a more efficient design.”
How does SIPs affect your energy bill?
“A good example is a house built near Independence, Va. It is 1,640 square feet and has yet to cost more than $70 a month in total electric use – that includes electric heat and cooling with standard use. “
How is SIPs being used in other parts of the country? How does Charlotte compare to other parts of the country?
“SIPs are used all over the country – more so in the Northeast and Northwest than other areas.
“Full SIPs houses are normally built by owner-builders and smaller contractors. My guess is that this will change as energy standards evolve more uniformly into the Home Energy Rating System for code evaluation. Charlotte is a conventional building market, but it is rapidly changing.”
Does it take any longer to build with this material? Do you need a specialized workforce?
“The need is for an intelligent, well-trained workforce. Speed depends, in large part, on experience and knowledge of the material. I can build as quickly as a good stick framer can. The speed advantage is that insulation and some interior finish is complete when framing is done.”
Are there other companies using SIPs in Charlotte?
“Not that I know of. Most SIPs timber framers work in specialized need markets or travel as I used to.”
Where else are you building SIPs houses?
“Gateway in Gastonia is a 38-house subdivision. Homes are 1,200-1,700 square foot and are priced from the $150,000 to $199,000 range. We’re building the project in Gastonia as the land costs provided to us by the City of Gastonia allows us to offer this product at this price level.
“We look at the project as ‘Urban Homesteading.’ The fact of the matter is that from downtown Gastonia to downtown Charlotte is a 25-minute commute. We’re hoping to attract teachers, firefighters and any other hardworking person excluded from entry-level housing to come explore this option.”
Photos: Courtesy of Green Apple House; Vanessa Infanzon
This story was originally published September 6, 2016 at 9:36 PM with the headline "How one builder uses special materials to build more affordable, sustainable houses around Charlotte."