I have a single wide trailer we are going to live in while we construct our home. The underside insulation is shot and needs to be replaced. Instead of putting the insulation between the joists they kind of made a huge blanket of it and stapled it to the underside then covered that with black plastic. The plastic is shot and a good portion of the insulation is missing.

My idea is to strip off the remaining blanket and put 6" insulation between the joists. Now for the question: Since I'm working from the underside is there any problem with putting the craft paper face facing the ground so that I can easilly staple it in place?

I am thinking of sealing up the bottom with 1/4" wafer board nailed to the joists with access panels for the plumbing.

-- Willy Allen (willyallen2@yahoo.com), September 09, 2001

Answers

First of all, the paper on the insulation acts as a vapor barrier. On my Jim Walter home that I built in 1982, I put the insulation between the floor joist with the paper side to the ground. I just sold the house last year and had no problems with the floor joist rottening. During the hot summer months here in Louisiana, the paper side would sweat some, with mold growing ocasionally on the paper. I think this was due to not having enough vents under the house to keep the moisture on the paper dry. I hope this helps.

-- JERRY TRAVIS (travis938@yahoo.com), September 09, 2001.

if i was gonna seal off the bottem with waffer board i would just do it and blow the insulation between the joists. the cheapest way to go would be to repair the stuff thats there and put up more plasic. how much are you willing to spend on a project that will go the way of the buffalo once the house is built?

-- paul a coleman (wormfarmerone@yahoo.com), September 09, 2001.

Hi Willy, We just insulated our new house. The carpenters had ordered the insulation. It was just like the insulation you are talking about only it did not have the paper. I was afraid it would scootch and/or fall. But boy .. once you stick it up between the joists its there. No stapling or anything. Then we ran the plastic over the top and then the drywall. Maybe you would consider using that. We have lived in the old trailers...and this old neglected farm house...both had drafts that could stand the curtains out on end! To get by here in the farm house...we ran the plastic around the north and west sides of the house, put up insulation board (the pink one) and set two high bales of hay around the bottom. We have not froze up once (praise to God).. and it was not that expensive compared to the heat bills everyone was paying. Do not know if this will help you out..hate to see you spend alot of time and money on something that is going to be temporary. We reused the insulation board and plastic on another project and the old hay went the way of composting. Have a great day and good luck!

-- Sher in southeast Iowa (riverdobbers@webtv.net), September 09, 2001.

Everything I've read on insulation said to put the paper side of the insulation next to the "warm" side of the house - I presume that this would be next to the floor in your case. This is, I guess, because the paper is considered a vapor barrier. So if you were insulating INSIDE the house, the paper would be facing you (or the drywall). Hope this makes sense.....

-- Bonnie (chilton@stateline-isp.com), September 09, 2001.

Put the paper side up next to the floor, its your vapor barrier.

Don't use wafer board. THat stuff will rot out, it just doesn't last. To keep critters out of my floor insulation and to keep the insulation up where it belongs, I used hardware cloth. If your joists are on 16" centers, buy 3' wide hardware cloth and overlap the edges. If your joists are on 2' centers, I'd still go with the 3' and just let it overlap by that much. Tack it up with a staple gun. I cut off lengths to go from joist header to joist header, 7' some inches to 8' some inches in length (that's how far apart my joist headers are).

-- Sojourner (notime4@summer.spam), September 09, 2001.

You need a product called "Tiger Claws" Ask your local hardware store about them and if they don't have them, the insulation place will. They're just very stiff pieces of wire that are sized to fit between the joists. You stuff the insulation up into the cavity (paper side UP), then jam the wire "claws" across the breadth of the cavity under the insulation (there should be a reccommended spacing on the box - if not, just ask where you bought them - but about every few feet or so should be more than sufficient). The wire is a tad bit longer than the space, and the tension really works to hold the insulation up there. You buy them by the box, and you'll no doubt have many extra (they're cheap). I have found that you can also bend the extras in half and voila - earth staples!

-- Soni (thomkilroy@hotmail.com), September 09, 2001.

Heres a wacky idea. Lay well sealed EPS sheets on the floor inside the trailer covered by 7/16" OSB. In effect raising the floor. Insulate the plumbing under the trailer and leave the rest well ventilated.

-- Yup (Yup@nospam.com), September 09, 2001.