The division produces a range of XPS insulation products under the GreenGuard brand, which it supplies throughout the USA from its manufacturing base in Virginia. The business had sales of US$84m (£50m) for the year to June 2014 and recorded an operating profit of US$10m in the period.
The enterprise value is US$82m, of which US$72m is payable in cash on completion plus US$10m of working capital. Gross assets being acquired are valued at US$30m. The agreement is subject to local approval of licence and permit transfers.
The acquisition will be funded from Kingspan's existing cash resources.
Kingspan CEO Gene Murtagh said: "This investment represents a new and exciting frontier for our Insulation business in North America, giving us particular exposure to the residential sector. It is a tremendous opportunity for Kingspan to build upon the growing success of our existing Insulated Panel business throughout the region, and at a time when North America's focus on energy efficiency and security is at an all-time high."