Insulate under floor

[mh_doni49]

Hi all! I need to get some insulation put up under my MH before winter hits. I have a handyman who is willing to go under and do it for me and he's charging me a reasonable price for his labor. I'll be paying for materials.

Since I wont' be able to get under there and help him and fiberglass/bellywrap would require two people under there, I've been researching options and am leaning towards buying sheets of rigid insulation (polystyrene). According to the documentation, every inch equals R4. So I'm looking to attach 3 layers of 2 inch sheets to the bottom of my floor joists (and I will take it down and around the HVAC trunk line to include that in the insulated space. I think this sounds like it should be a lot less labor intensive and will result in an R value of 24.

But I'm having trouble figuring out what to use for actually attaching it to the joists. I need to support each layer while the subsequent layer gets put up. And as each layer goes up, it'll get thicker and thicker. Which means that whatever we use has to keep getting longer and longer.

When hanging the last layer, I'd need to go through 6 inches of insulation and into the joist.

Any ideas would be greatly appreciated! TIA!

[Greg S]

Forget the rigid foam. It is way too labour intensive to use in a confined space under a home. Your best option is Roxul. It is waterproof, unlike fiberglass insulation, and available at Home Depot. Don't forget to install the vapour barrier against the floor and around under the floor joists before placing the insulation.
Much easier to place under a home and no fiber glass to deal with. I would suggest you insulate your skirting as well.

[mh_doni49]

If I don't do the sheets of polystyrene and do either fiberglass or this roxul then I'll have to do the belly wrap too.

I'm really confused as to exactly how the BW should be installed. The article I read on this site regarding belly wrap replacement seemed to talk about attaching it to the floor joists next to the main I Beam. Does it just get attached to the joists on either side of the beam? Do I need to somehow include the beam in the insulated space? Should the insulation go above the I-Beam between the joists with no barrier and no BW?

[ANav1982]

I have a (noob) question about this as well ...

As far as attaching underbelly wrapping to the underside of a Mobile Home, can you just use a staple gun to nail it to the floor beams under the Mobile Home, or is that not wise?

The entire under belly to my dining room was shredded somehow and I ripped whatever was left off and tossed it ( I may have pictures somewhere ), knowing I would replace it later. Well I have the time and inclination to replace it now, but don't know if I can just staple-gun it to the exposed boards underneath? I'm sure it's not as confusing a process to do and I'm probably over thinking it, but the logistics are confusing me slightly.

[Greg]

I have a (noob) question about this as well ...

As far as attaching underbelly wrapping to the underside of a Mobile Home, can you just use a staple gun to nail it to the floor beams under the Mobile Home, or is that not wise?

The entire under belly to my dining room was shredded somehow and I ripped whatever was left off and tossed it ( I may have pictures somewhere ), knowing I would replace it later. Well I have the time and inclination to replace it now, but don't know if I can just staple-gun it to the exposed boards underneath? I'm sure it's not as confusing a process to do and I'm probably over thinking it, but the logistics are confusing me slightly.

Insulation in mobile homes are designed to hang down under the joists like a big blanket. The reason behind it is to allow warm air from the heat ducts to circulate and keep the plumbing warm. If you staple to the floor joists you will shut off the circulation. If you are in a warm climate this is usually not a problem, but if you are up north you really don't want frozen pipes.

Another option is to use insulated skirting. Mark (site owner) has done his in S. Dakota and claims the temperature never drops below freezing. Check the articles section of the site, I think he did an article on it.

Greg

[ANav1982]

@ Greg :

I'll keep my eyes out for the article on that. You wouldn't happen to know the exact title would you? If I have that it might be easier to find. *random thought* Couldn't I also use something like : http://www.lowes.com/pd_15348-236-11079 ... facetInfo= this in lieu of the underbelly wrap ?

I didn't know about the circulation aspect and that's good information to have. I'll post a link to the article once I find it just in case anyone else has similar issues (or should I start a new thread so I don't hijack this one? ). Since I live in South Florida I'm not concerned with freezing pipes at all because that's just not a thing that happens here (thank the gods).

I need to look under the Mobile Home and find the bathroom pipes because if those are under the floor I would prefer to have them in the walls. I'm in no hurry to start that particular project though!

[Greg]

I don't see it, It may have been on the old version of the site (am I getting that old?). There are a few pages on it the the repair manual that Mark has.

I think once you get started on your projects I would start new threads.

Greg

[1987Commodore]

http://www.mobilehomerepair.com/article6.html
There's this one, but I think I remember another one where someone posted their own.