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Hi all.. I am having to replace the insulation and tarp stuff under the back end of a 16x66 single wide (master bathroom area) due to a water leak and after pipes were fixed they didn't replace it. Ugh. So I am taking the advice of the book and I got the Insulation and 1x4's and am picking up the tarp stuff this morning (size 10'x16') and hopefully they'll have the flex mend tape stuff but I had a question. Once I lay the tarp stuff down then the insulation over it do I then use plastic over that? In pictures I've seen on here when someone's fixing their floor I see clear plastic between the inslulation and the floor. I know that's probably a stupid question but since I've never done this before either - ha ha - I need advice. From what I've been reading on here you have to cuz your pipes might sweat and get the insluation wet, ect. Just let me know if thats right. I'll take pics of it this morning and afterwards when i'm done to post.

Thanks guys and god bless.

Traditionally the plastic underbelly material also acts as the vapor barrier, but since the insulation does not go up tight against the joists (you want some dead air space for air to flow) it may be almost a good idea to put plactic on the floor side of the insulation to protect it should you have another leak.

If the belly is still open and you have ANY doubts about the plumbing, I would replace it now. Greg

Yeah you gotta think about how much moisture is going to evaporate up from the ground. Now dont quote me on thins but the tarp material is probabally so the insulation can breathe so it doesn't rot and mold and the plastic is to keep moisture from reaching the floor joist and sub-floor and rotting them. While choosing the plastic for your vapor barrier keep in mind tat they built these homes as cheap as possible to make more money so choose plastic that is thicker than the exsisting and use a thicker insulation if possible too but dont pack it in rael tight cuz you will loose the R-value those fluffy little air pockets inside the insulation give a place for cold and warm air to meet and that is why you shouldn't smash it.

Hi

In this geographic area (Florida) it is NO clear plastic between the inslulation and the floor. Around here the more ventilation the better.

Harry

Ok sorry, but maybe I'm not understanding yall. I read that your not suppose to put insulation around pipes near floor so that's why i thought the plastic stuff was suppose to go there. I'm in Arizona so there's not much moisture, except for monsoon season. They replaced all those pipes so we're good on that end. Also wanted to find out why i couldn't just go and staple it to the floor joists. Lets say there's no pipes down a certain row or whatever and i put the insulation up inbetween the floor joists, with the plastic on top it that, could I then just use the staple gun to keep it in place??

Again, I'm going with the factory setup, that may or may not apply to your area.
The underbelly & insulation is designed to hang down BELOW the floor joists, this allows for an air space. In colder areas where freezeing is a factor the air in that space is warmed from the heat ducts, this in turn keeps the plumbing from freezing.

Now since you are in Arizona this may not be your case. My thoughts of putting the plastic on the floor side of the insulation was to protect the insulation some should you have any more water leaks. I would figure out a way to allow any water to drain out to alert you should you have a leak again. a diper that big will hold a LOT of water. Greg

Thank you so much greg for answering me so quickly. I'll take pics and let you know how it goes later today. I am going to not use the plastic so we'll see.

ok quick question.. i am at black pipes that are coming off the shower so do i put the insulation up in the floor against those or keep it underneath those??

As long as freezing weather is not a factor, It should not make much difference. Greg