News From Go Plymouth Foam

"Or Equal" - How about Better than Equal

Many construction architectural specs are written with a phrase that reads , “or equal.” This typically means that product must be at least equal to what is being called out. Many architect specify XPS (Extruded Polystyrene) for below grade insulation requiring an R-Value of 5 R/inch with a PSI of 15 or 25. Most times that foam board is specified as 2” thick to accomplish R 10. The real question may be, are their foam insulation boards that are “equal” to XPS below grade?

Plymouth Foam announced in January 2016, that they have
developed a new line of insulation products called Graphite Polystyrene (GPS). Working with BASF’s Neopor Plus ® this new foam insulation board delivers a stable higher R-value by infusing high-purity graphite particles into the Expanded Polystyrene cell structure. This new product has been tested and results conclude an R-value of 5.3 R/per inch* at 40 deg.

Neopor Specs
*The technical and physical metrics provided in this table are reference values for insulation products made of Neopor GPS.
The values and properties may vary depending on how they are processed and produced. The R-value properties are based on 1-1/32 in thickness.


The new innovative GPS foundation insulation certainly inhibits all the characteristics that make it an equal or better than equal to XPS insulation. In fact, GPS is far superior to XPS in a more stable r-value (see below grade insulation study), has the ability to expel moisture and even holds most of its r-value when wet. On the of other hand, XPS’s r-value decreases when the blowing agent escapes and when it gets wet.

The conclusion is simple, it is time start specifying Plymouth Foam’s GPS insulation for those foundations insulation needs.