I have RFH in 1.5″ of gypcrete on my first floor with a 10′ poured basement below. I’ve read that the underside of the floor should be insulated. The floor system is 12″ I joists on 16 centers, 3/4 & 1/2 Advantec then the gyp with tile and Santos Mahogany (about 60/40) for a total of 1700 sq. ft. The basement workshop (100%) does have it’s own HW unit heater, zoned off the boiler. There is also a large woodstove.
The question is am I really better off with a double faced foil/foam type insulation vs FG with a vapor barrier? Most of the plumbing and AC duct work is inside the joist bays so access to the bottom of the joists is near 80% available. 4′ strips off the roll would be toooo easy.
I have no current plans to install a drop ceiling and would never SR it. Looking at all that shiny insulation might make me think I’m working on the set of Lost In Space with the robot. I’m not so sure I want FG up there as it does not reflect the RFH ‘up’ back where it belongs into the 1st floor living space. Right?
Currently the basement temp was very close to the 1st floor setting, within 6 degrees anyway.
Am I all wet on this?
Replies
As long as the insulation is installed well, I wouldn't care what you use, though if the basement is unheated I'd want to see at least an R19 if it's well sealed, R30 if not. The basement probably stays about the same as the first floor because you're bleeding heat, I've seen 80 degree basements from joist systems .. downward heat gain is very real.
I don't trust reflectivity for long term benefit, personally, and do not advocate for reflective surfaces in joist insulation.
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
The basement is tight. I must have some heat to protect water lines and drains. That's one reason why there is a unit heater. I fully believe your bleeding heat statement.
I'm a little confused however on the long term benefit statement. Are you saying to pack it in tight to the floor so it can't travel down? Do you not see a need for reflectivity? Is this hype?
TIA for your insight. I know I don't want to look at a pink or brown paper ceiling.
Yes I saw the white side stuff. I was a little concerned with melting from the woodstove. They both (foil or wht) would cut the need for shop lighting. :-)
I don't believe that products which rely on reflectivity hold up long term. I've never seen a clean joist bay and it has been established that dusty conditions do reduce reflective products' effectiveness.. admittedly, in more extreme circumstances, so you could debate my view on the matter for sure.But personally, I prefer to rely on real R-value, not "R value equivalence". Reflectivity can help at least for awhile, but I don't want to be guessing about what's going on down the road. So yes, I'd put it in tight.Also, be sure to pay special attention to the joist ends and seal them up tightly. That can be significant infiltration right against your emitter..-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Thank you kindly for your advice.
Bubble foil is also available with one white surface.
Kraft face needs to be covered.
unfaced bats w/ white faced bubble foil?
Garett