Hello Mary: I'm glad you're building a dome, but before you do, please check out www.monolithicdome.com I took David South's 5 day building class, in Italy Texas and it was the best money I ever spent. He will direct you to a REPUTABLE dome builder in your area. Concerning your radiant floor heating system, please post your question on "The Wall" at www.heatinghelp.com the guys there are the best at what they do, and will help you find someone locally who KNOWS exactly what they're doing. If you need a tankless heat source for your system (gas or electric) please let me know if I can help. Best of luck, Brian at 800 851 9891.