WhatScience? wrote:aniSUKSatCHEM wrote:Alex-RCHS wrote:I've found other reasons why Polyurethane may not be the best option. Closed-cell foams decrease in R-value per inch over time as some of the gas trapped inside the cells escapes. It probably will not have much of a negative effect, but it's enough to dissuade me from using it.
What do you mean by "over time"? I think your perspective on this is quite interesting, and something worth considering. Do you think this will be a major problem over the course of two months, for example?
Alex, should still answer this but from personal experience...I still haven't noticed a difference
In fairness, I haven’t tested it either, but that’s why I said that I wouldn’t use it, not that it was bad.
The truth is I’m not sure. But if you look up “polyurethane insulation over time” or something like that you’ll find many results. I’ve seen values saying that there’s a significant difference after just 6 months, but I’ve also seen that there’s no significant change after 2 years... I’m not really sure which is right, and it’s probable that the effect is negligible but it’s not a risk I’d like to take, personally.
Edit: here’s a link:
https://www.ncptt.nps.gov/blog/new-repo ... -released/
The x axis on that graph is kind of misleading because that is time spent in an aging chamber; it’s unclear how what the real-life time scale is.