foil insulation for crawlspace
melteach
| Posted in Energy, Heating & Insulation on
I have a crawlspace that could use some insulation. I barely fit between the dirt floor and the joists (can’t if I forget to take a long screwdriver out of my back pocket). I was wondering if I could use the rolls of foil bubble wrap looking insulation for this purpose. Thanks for your help.
Replies
Friend,
If things are really tide down there, it may be worthwile subcontracting it. If something falls after is done, well, you could call them back. It is easy for it not to be done right.
Yeah, but you simply won't get the insulation value out of that stuff. Fill the floor joists w/ insulation and provide a solid support (twine or lath or tyvek) to hold it in place. While you are at it ... seal the plumbing/elect going up through the floor before you install it.
Doesn't fiberglass need to be covered with drywall to meet code? Or could I use the foil over batts for a fire break. Thanks for the ideas.
Any exposed insulation needs to have a flame spread rating. I know enough to be dangerous in this area. I'm a little rusty in the specifics. That being said ... Most of the time the flame spread rating applies to the vapor retarder attached to e.g. fiberglass insulation. Thermax has a rated foil, I think. Polystyrenes typically do not. I think the code specifically says that e.g. polystyrenes or other foams need to have a rated material in substantial contact w/ the foam ... in other words ... don't leave an air gap in a wall that will promote flame spread.
Fiberglass - not sure. In itself, it doesn't need 'protection'. How protection relates to e.g. exposed insulation in attics and crawls, I'm not sure. You see exposed insulation all the time (by code), so I don't think it is an issue.
Best bet ... talk w/ a BO about your situation and your ideas and he would give you a good idea of what you can/can't or should/should not do. Maybe some others will jump in here w/ a few more words of wisdom.
Depending on where you live, of course........in our area - NW Wisconsin - the preferred recommendation for crawl spaces is to insulate the outside or inside of the crawlspace walls with 2" of insulation. I do like the bubble insulation, and we have some in our crawlspace on top of the insulation.
Remember, the bubble wrap insulation does not have a particularly high R-value ... so if you used it, you'd have to use multiple layers.