Timber frame homes are most often enclosed with structural insulated panels. The panels offer exceptional performance, quick dry-in, and minimize onsite waste.
While expanded polystyrene panels offer all of the above and are widely used throughout the industry, polyurethane is the choice of some companies, including Goshen Timber Frames.
There are discussions about the “greenness” of both products everywhere. Since both are petroleum based products, the purist will argue that neither should be used in construction. However, the long term energy savings offset this argument.
A recent Environmental Building News article (you can read about it here) brings into focus some of the differences and argues that polyurethane is the better choice for above ground applications. A search for discussions about the panels will find manufacturers and salesmen of both products making a case for their product. However, independent research has led Goshen to use only polyurethane, as the best, safest, most efficient enclosure system. We are not invested in either product and have made our decisions based on our years of success with polyurethane and our own research.
There are many, many more companies manufacturing expanded polystyrene panels than polyurethane panels. The process of manufacturing polyurethane panels requires a greater investment and fewer companies are willing to make that investment. This should not be seen as a vote for EPS as the better product, just the most economical to manufacture.
Discuss your enclosure options with your timber frame company. While I firmly believe that panels are the best way to enclose, I also believe that polyurethane panels are the best of the best.
That said, I”ll sign off for now.