B&H
Well-known member
This summer, we expanded our auto repair shop from 2 bays to 4 bays. Back in 2009 or so, we removed the old concrete floor in the original side of the building and added radiant floor heat, good drain system, new lifts, etc. At that time, the contractor convinced us to use the foil-type radiant "insulation" under the slab. We did some research and it seems that you can find pros and cons on about everything, so we went with what the contractor recommended.
This year, we added 2 more bays, office area, new bathroom, break room and a storage room as new construction. We used radiant floor heat under all of the new area except for the storage area. We used the existing boiler that we installed back in 2009. When we discussed the flooring, the contractor (different one) hadn't even heard of the foil stuff and had always used XPS w/o any problems. He convinced us that the XPS was the way to go, so we went with it, 2" 60,000psi.
Without a doubt, we can "unscientifically" tell that the XPS is much better than the foil. The slab warms up much quicker. I ran into the architect a few weeks ago and asked what his thoughts were - he laughed at the foil-backed insulation!
I think that contractor #1 for the floor redo in the original building was either really trying to cut costs or was incompetent or both. I was willing to pay more, but was told that you have to look at the entire picture when insulating, and that they have had the foam boards collapse under the concrete where the transition was from outside of the build to inside.
So, if anyone is searching these threads for info on this subject, and having done it both ways, I would clearly recommend using the foam board vs the foil stuff. If a contractor doesn't want to use the foam board and tells you that the foil is the way to go, find another contractor!
This year, we added 2 more bays, office area, new bathroom, break room and a storage room as new construction. We used radiant floor heat under all of the new area except for the storage area. We used the existing boiler that we installed back in 2009. When we discussed the flooring, the contractor (different one) hadn't even heard of the foil stuff and had always used XPS w/o any problems. He convinced us that the XPS was the way to go, so we went with it, 2" 60,000psi.
Without a doubt, we can "unscientifically" tell that the XPS is much better than the foil. The slab warms up much quicker. I ran into the architect a few weeks ago and asked what his thoughts were - he laughed at the foil-backed insulation!
I think that contractor #1 for the floor redo in the original building was either really trying to cut costs or was incompetent or both. I was willing to pay more, but was told that you have to look at the entire picture when insulating, and that they have had the foam boards collapse under the concrete where the transition was from outside of the build to inside.
So, if anyone is searching these threads for info on this subject, and having done it both ways, I would clearly recommend using the foam board vs the foil stuff. If a contractor doesn't want to use the foam board and tells you that the foil is the way to go, find another contractor!