- Feb 11, 2010
- 149
I called up a local company that deals with spray foam insulation. They've done underground boiler lines for apartment buildings before, so it's not an entirely new process to them. The guy quoting me told me to space the lines 2" apart and space them 2" off the ground with foam blocks. He's going to put 2" all the way around and in between. The quote came in at $9-$10 per foot (or $720-$800 for my 80' underground). Add that to the cost of the 1-1/4" PEX and I'm looking at about $11.50 per foot insulated not calculating the cost of me renting the trencher. Is there any well-made pre-insulated 1-1/4" pipe that comes in around that price?