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the ins and outs, pros and cons of better bellies

Posted: Fri Oct 28, 2016 2:47 pm
by suspiria_2
ok, i am a new member and new to mobile homes and new to repairing anything. about the most i've done before is paint, hang drapes, etc. due to life-long apartment living (yech!). just to get that out of the way.

we have somewhat inherited my spouse's father's mobile home (a 1997 some brand or other single wide) which is in probably not the worst condition anyone here has ever seen, but it isn't looking good, either. a few years ago, the house sprung leaks everywhere and the piping had to be replaced. of course, they tore out the soaked insulation and ripped up the belly to do these repairs, and probably didn't patch anything under there, although it is hard to see due to the masonry block skirting his father built himself (master mason) and the metal support structure and pier-type support blocks obscuring the view.

so, i have been and will continue to be reading up on this here, and all over the internet. it seems that there are a few ways of going about reinsulating and redoing this belly, and i wanted to know what various people have tried/used and how much success they have had with it, not only in application but also in the end result (saving energy on heating/cooling and keeping out moisture, right?).

we were looking into that radiant bubble-wrap type insulation that staples in and seals with tape. i have also read good things about using foam boards, also sealed with tape, in regards to some Building Science studies done in hot, humid southern climates (we're in Alabama). my thinking is either to do these alone over the very bottom of the joists, as the radiant barrier needs airspace around it, or to add infill insulation and i have no idea which would be best.

another item of concern is critters--we are on an old farm which has returned to wilderness and there is everything out there, including gators, snakes, and a lot of rodents and insects. I was thinking hardware cloth over the whole of the underside, or soffit venting but i have no idea if this effects the moisture level or insulating qualities of whatever it is put up against.

needless to say, i will be caulking and liquid nailing like mad, as we are also redoing the subfloors throughout at the same time and i want to make good air seals everywhere possible. i know that one of the most important things is to make sure all the ducts and piping is inside the insulating layer. aside from a having a discussion about the various ways to insulate a belly, am i forgetting anything?

Re: the ins and outs, pros and cons of better bellies

Posted: Fri Oct 28, 2016 5:14 pm
by Greg
Since you are in the South, freezing weather is not much of a factor in your case. As long as the blocks are tight with no gaps you may be fine with minimal insulation. You DO however need to make sure you have proper ventilation.

Greg

Re: the ins and outs, pros and cons of better bellies

Posted: Sat Oct 29, 2016 9:50 am
by suspiria_2
ventilation within the crawlspace itself? there are vents in the cement block structure.

or do you mean ventilation from the house to below the subfloor or vice versa?

Re: the ins and outs, pros and cons of better bellies

Posted: Sat Oct 29, 2016 1:11 pm
by Greg
No, I am talking about the space between the ground & belly (crawl space). The general rule is a minimum of 1 sq. foot of ventilation for every 150 sq. of floor space. This will allow for ground moisture to escape before entering the home.

Greg

Re: the ins and outs, pros and cons of better bellies

Posted: Mon Oct 31, 2016 6:04 pm
by suspiria_2
thank you for responding.

i am still considering my insulating/vapor barrier options for this belly.

however, i think we are covered on the ventilation in the "crawl space". we believe that the masonry wall doesn't meet the bottom of the trailer, so there is an air gap all around hidden by a vinyl strip. there are also regularly spaced vents, although i have not measured them, and two 30" square doors.

how to keep rodents from the surrounding fields out of all of these airholes is an accompanying issue. but i was really more concerned in this thread about my choice of belly insulation/barrier. foreseeing future plumbing work or even leakage, we might actually go with something that fits within each cavity, like a foil faced fiberglass batt, and seal the edges with tape. i think i have decided that the air bubble wrap is probably not sufficient for this particular job.

thanks again for your help.

Re: the ins and outs, pros and cons of better bellies

Posted: Mon Oct 31, 2016 6:30 pm
by Greg
Fiberglass over bubble wrap. Bubbles are great for packing, just don't have much faith in them for insulation.
You could stuff some steel wool in the holes and then go over it with spray foam. the steel wool will keep critters from chewing through it.

Greg

Re: the ins and outs, pros and cons of better bellies

Posted: Tue Nov 22, 2016 9:04 pm
by JD
I have been in the mobile home repair business for over 30 years. I have done most every repair from roofs to sets and relevels and every type of remodel in between.

My thought is that you may be over thinking the under belly. I would recommend using the very affordable mobile home underbelly that is available from Mark here on this web site, under the books and posts link. This is the correct material and easy to install. JMO

JD