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Recommendations for insulation under belly

Posted: Fri Sep 27, 2019 1:39 pm
by mdnagel
Q: Would mixing R-value insulation be a waste of money?

Underbelly has areas devoid of insulation. Maybe max of 150 sq-ft. Repairs, by previous owner, left belly wrap open and some crap insulation was tossed in but then pretty much sagged out (I've yanked it).

I have run out of time to do a proper repair on this, but would like to at least try to get some decent insulation installed such that it can have some effectiveness. No concern of pipe freezing: hasn't happened over the course of many years (even with our heating solely via wood stove).

I like to improve things when I can, in which case I'm thinking that going with a higher R-value insulation would be an improvement. But, seeing as this is only ever going to be a partial replacement (no plan on re-insulating ALL) I wonder if a higher R-value wouldn't be just a waste of money (kind of like when one replaces only one battery in a bank of batteries in which case the higher voltage of the new battery is never realized due to the lowered voltages on the existing aged batteries).

I would prefer to work with rockwool. Around here that insulation seems to only be available in faced batts, which would mean that I'd be needing to install between the floor joists.

Again, this needs to be a down-and-dirty, quick operation. No time to do any belly wrap patching and such: I don't want to do any because I still plan on doing the re-plumb work, though not this year. Big objective was to critter-proof things by doing a re-skirt (which also required a rim joist repair); this is nearly done (and now the weather is really shifting to rain- I still have to put up gutters [destroyed by last year's snow]!).

Re: Recommendations for insulation under belly

Posted: Fri Sep 27, 2019 6:10 pm
by Greg
Insulation is like a chain, it is only as strong as it's weakest link. The R value will only be as high your lowest R value.


Re: Recommendations for insulation under belly

Posted: Sun Oct 13, 2019 5:52 pm
by Mark440
being my skirting was plastic - and critters had chewed clean through it in multiple places....and being i was tired of patching holes in the belly....I had all of it torn completely out. Had a company come in a spray foam on the entire underside, and then installed metal skirting with an abundance of pea gravel on the outside. Then i ordered some peppermint oil, l9oaded up a sprayer and saturated the pea gravel with peppermint.

Foam spray - $1600
Re-route all HVAC ducts - $2400
Metal Skirting - $750 (installed myself)
Pea gravel - $100
Knowing i beat them damned critters??!!?? PRICELESS!

Re: Recommendations for insulation under belly

Posted: Wed Oct 16, 2019 9:32 am
by Mark440
uh-oh......I got to back track on the win.

Was out just kinda of checking on things....and one corner has some terrifying signs of breach.

I used landscape timbers - turned up on edge, then staked to contain the pea gravel at about 6" out from the skirting panels. The depth below grade is about 3 inches, and the depth above grade runs from 3.5 - 5+ inches - depending on contour. This particular corner is in the 5+ inch range ......yet there it was plain as day: a little dug out....and no....the pea gravel did not cave back in. my experience....I am going to have to call bull&*#$ on the selling point of pea gravel. What ever the critter is/was - it just shoved the pea gravel out - up and over the landscape timber - to gain access. Pea Gravel: quaint idea that just doesn't muster.