I'm wondering what the best methods are for insulating between or underneath the floor joists when you have radiant tubing below the subfloor to heat the floor above?
Is it important to have a reflective layer (such as on foil faced foam sheathing) and would that be even more important when using Onix staple up vs. PEX with reflector plates?
If the heated floor is above an unheated crawlspace, it seems like either fiberglass or rock wool batts between the joists (with an air gap between it and the radiant tubing) would provide the best insulating value from the cold crawlspace. What would you put below the joists and insulation? Foil faced foam sheathing? 7/6" OSB? Typar? Just some wire to hold the rock wool in?
I'm not really looking for Onix vs. PEX w/ reflector plate advice, although if people want to debate that, that's fine. In my case, the guy who installed my oil boiler eight years ago talked me into using Onix for the 1st and 2nd floors of the house. Because my house is very well insulated, the Onix with 110 F water and 1" of foil faced foam below has been getting the job done. Last year when I removed a post in basement and put in a laminated beam, I had to remove three 200' loops of Onix which I haven't put back up yet. I'm thinking about using the Onix in my workshop, which will be over an unheated crawlspace. The floor will just be a single layer of 3/4" OSB which will be painted on top. The 1st floor of the house would then get PEX with reflector plates. I'm thinking that the Onix would be a heck of a lot easier to staple up in the workshop crawlspace than dealing with PEX. The workshop will be fairly well insulated, but not quite as well as the house. My primary heat source for both buildings will be the wood boiler and tanks in the shop, so I would like to have as little heat as possible flowing underground when heating the house. Thoughts?
Is it important to have a reflective layer (such as on foil faced foam sheathing) and would that be even more important when using Onix staple up vs. PEX with reflector plates?
If the heated floor is above an unheated crawlspace, it seems like either fiberglass or rock wool batts between the joists (with an air gap between it and the radiant tubing) would provide the best insulating value from the cold crawlspace. What would you put below the joists and insulation? Foil faced foam sheathing? 7/6" OSB? Typar? Just some wire to hold the rock wool in?
I'm not really looking for Onix vs. PEX w/ reflector plate advice, although if people want to debate that, that's fine. In my case, the guy who installed my oil boiler eight years ago talked me into using Onix for the 1st and 2nd floors of the house. Because my house is very well insulated, the Onix with 110 F water and 1" of foil faced foam below has been getting the job done. Last year when I removed a post in basement and put in a laminated beam, I had to remove three 200' loops of Onix which I haven't put back up yet. I'm thinking about using the Onix in my workshop, which will be over an unheated crawlspace. The floor will just be a single layer of 3/4" OSB which will be painted on top. The 1st floor of the house would then get PEX with reflector plates. I'm thinking that the Onix would be a heck of a lot easier to staple up in the workshop crawlspace than dealing with PEX. The workshop will be fairly well insulated, but not quite as well as the house. My primary heat source for both buildings will be the wood boiler and tanks in the shop, so I would like to have as little heat as possible flowing underground when heating the house. Thoughts?
