Underbelly project - need advise

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I'm a newbie both to this site and to MH ownership. I recently purchased a 1979 Metamora 24X40 double wide located in Central Texas near Austin. The home has sat at this location since new.

This last weekend I cut out a 4X8 section of sub floor in the living room to determine why it had buckled. When I removed the particle board I could see all the way to a wet looking dirt area. The insulation and underbelly cover had completely fallen away in this area blocking all air flow and this will all need to be replaced. I didn't have time to investigate the source of the wetness, and since had rained recently, it could either be bathroom water or rain water in that area. I will obviously fix that problem first,

I have a million questions that I will probably post in separate threads. My question here is this: When I have installed fiberglass batt insulation to a raised floor stick house, we installed it between the floor joists with the Kraft faced vapor barrier touching the sub floor so it was facing the living space. As I understand the installation of the polyethylene underbelly material, the instructions indicate that the vapor barrier side would be glued to the polyethylene, thus the vapor barrier would be on the bottom of the floor joists when installed. This seems to but the vapor barrier in the wrong place to avoid condensation in the fiberglass. What is the best way to install new insulation to the floor of a mobile home?

I also noticed that none of the HVAC ductwork is insulated and it all was sweating with the A/C turned on. Shouldn't this be insulated?

My guess is that I will be spending a week under this thing replacing most if not all of the insulation and underbelly material since it is all in bad shape. Any pointers or suggestions will be appreciated.
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Greg
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Hi Tex, Welcome to the family. I will stop short of saying forget everything you know about construction of stick built homes, but Mobiles are different and do have some quirks. My first recommendation would be to purchase Mark's book, He is the owner of this site and his book is a bible for mobile home owners. It covers all aspects of mobile home repair in a general way.
As for repairs, find the source of the moisture first and get things dried out. You may want to check the home for being level before getting too involved (leveling is covered in the book also), since if you do work on a home that is not level everyting you do is out of level also.
Do yourself a favor and use PLYWOOD to repair the floor. The insulation should be under the heat ducts with the vapor barrior down. There are a lot of things you can use for belly wrap, some use plastic, some use tyvec, some use plywood and the list goes on.
You have found the best site in the world for mobile home repair, and the best support team, I'm sure others will have more ideas for you. Greg
"If I can't fix it, I can screw it up so bad no one else can either."
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Yanita
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Hi,

Although some will disagree with me I still firmly believe in a moisture barrier. Depending on where you live this can be code, some insurance companies require it, it is nothing more than sheets of 6 mil plastic laid directly on the ground. Over lap the seams in the plastic and cover from end to end, side to side under the the home. This prevents any ground moisture that evaporated from being wicked up under the home, especially if your under belly material is damaged or not there at all.

Glad you found us, everyone will help you in your repairs. The manuel as Greg suggested, will help you understand the construction of our homes, and the proper repairs. Of course even with the manuel we will help you along! :D

Take care,

~Yanita~
The difference between success and failure is who gives up first!
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Robert
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Hi,

Welcome aboard !! The ductwork is left uninsulated so as to allow the heat transfer enough to inner belly area to keep the waterlines from freezing.

It is sweating due to the cold metal being in contact with warm ambient air because belly material is opened and torn.

Once the belly and insulation is replaced/repaired, the sweating will be very little or non-existant.

Take care and best wishes,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
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JD
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The underbelly material is available here at http://mobilehomerepair.com/underbelly.htm

I have purchased this through Mark a couple of times. Excellent service and price. He also sells is in smaller quantities if you don't need the 16x80

JD
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All information and advice given is for entertainment and informational purposes only. The person doing the work is solely responsible to insure that their work complies with their local building code and OSHA safety regulations.
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Thanks for the replies. The first thing I did after finding this site was order the repair book. I should get it in a week or so. I think I understand the original manufacturing concept of simply attaching a blanket of insulation under everything to somewhat seal the bottom and to insulate everything at once, while providing protection to the plumbing. This home has had a stone "skirt" installed around the perimeter making it difficult to work under. I also suspect the vents are too small for the enclosed space. I think that a very large portion of the original underbelly has been damaged over time with so much of it hanging loose and ripped that I will need to start from scratch. I'm not sure I want to attempt to put it back the way originally installed at the factory since it seems like it will be very hard to maneuver the large sheet of underbelly material, with insulation glued to it, around the many obstacles such as the plumbing, HVAC ducts, steel Ibeams and axles. I'm considering installing fiberglass batts with the vapor barrier next to the floor, between the joists, and sealing the bottom with rmax 4X8 sheets of foil faced 1/2" foam board. To provide a little ventilation inside the sealed joist area I can install small vents like those used with overhangs on a stick built house. The duct work that does not have plumbing next to it can be separately insulated, and the areas that have plumbing I will make sure is insulated to include the heating ductwork. While this is not in compliance with the original manufacturing technique, and is more costly to do, I think with my limited working space, I can successfully install smaller areas at one time. Does this make since or is the installation of a new underbelly blanket easier than I think. I can't remove the "skirt" and will need to do all this in the limited space under the house. What type of critters will I likely run into?
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JD
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Hi Texas,

We install buffalo board when the home has buffalo board and the polyethylene belly wrap when they have that. Personally, I find working with the belly wrap much easier than dealing with the 4x8 sheets. But we always have at least 2 guys under there and sometimes a 3rd guy cutting material for us outside. And usually it is pythons, yep big pythons under there. :)

JD
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kashton
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LOL... Sorry for the chuckle, But The Buffalo board in my room is all on the ground under my trailer. Didn't know until I had to replace the floor. That is the only room that now has two layers of plywood and carpet until I can get under there to deal with it.
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PYTHONS! YIKES! I hope we don't have those here. What is Buffalo board?

What does it typically cost to have a new blanket installed by a professional. The one I have just doesn't look like it can be repaired.
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JD
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Hi Texas,

Buffalo board is a black, very lightweight fiberboard about 1/2" thick. Comes in 4x8 sheets. I think it is made mostly with cardboard fibers. It is asphalt impregnated on one side to deter pests and stop moisture that evaporates up from the ground.

About critters, in 18 years of mobile home repair, I have only confronted a couple of cats and rodents and they were just blurs in my peripheral vision as they scampered off. I have heard of other workers seeing possums and racoons. I did have to de-smell the under side of a home that had a skunk/cat fight under it. But critters have really been a non-issue for me.

What I REALLY don't like are spiders. Here in Central Valley, California, almost every home has black widows. and in my eyes, any spider that is not a widow or daddy longlegs has to be a recluse. But in all these years, I have never been bit by a widow or something as bad. A few minor bug bites but nothing that was serious.

There very well could have and should have been at least a few snakes like rattlers, rat and garners but I have never seen one. I imagine they get away when they see us crawling around down there. I was just joking about the pythons. They like high places like trusses and above cabinets.

JD
☯JD♫
Today is PERFECT!

All information and advice given is for entertainment and informational purposes only. The person doing the work is solely responsible to insure that their work complies with their local building code and OSHA safety regulations.
Lane
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Location: Quinlan, Texas
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Hi Texasj10, and welcome to the board. I seriously doubt you'll have anything like JD mentioned, but all the other four and eight legged, along with other variety of snakes might be a possibility. I'd take the time to set off some insect bombs under the house to take care of the spiders and maybe some mothballs (about 1/2 box in your case) to keep the others away. Just broadcast the pellets across the ground. Don't need much, or you'll have the smell coming in the house.

That said, your idea sounds viable to me. Yes, more costly, but might be less on the heating/cooling costs as well. Your water issue might be a leak, but maybe more so related to the recent heavy rains we've had in areas of Texas. Everyone here will provide ideas and 'how-to' that they've experienced in similar repairs. Feel VERY free to ask ANYTHING you're uncertain about or want to confirm from an outside source (like HD, Lowe's or other) that seems odd to you. That will avoid costly mistakes and loss of the time in re-doing the job. AND, there might be easier, less expensive solutions.

I'm about 45 miles east of Dallas myself, on Lake Tawakoni (pron tah-wa-ko-nee). Having done a lot of similar repairs on my own SW, I know what you're going into so ask and if I can help, I'll gladly do so.
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Maureen
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I just want to make sure that if you use the moth balls, you just use a few, per square feet! It doesn't take much at all! If this does work for you, they do need to be replaced every 3 months or so.

I've also been under my home more times than I'd like. I've never seen anything other than spiders. I have noticed that with a few wet Winters behind us, that with the dry Winter we had this year, the spiders have really moved in 'down under'. I might have to set a few 'bombs' off this Spring.

Keep in mind that if you use bug bombs under our homes, the fumes can get into your living space very easily. Use caution there!

Maureen 8)
Never discourage anyone...who continually makes progress, no matter how slow.
'Plato'
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I spent the weekend under the house and it looks like I will be spending the whole summer there. All of the underbelly tarp has disintegrated and the insulation is on the ground. The main duct work has fallen on the ground and plumbing is a mass of messed up PVC installations. I found several areas where the particle board sub floor rotted away. It's an old home in need of some repairs. I bug bombed the underside with some raid fumigators a few days before I went under. I didn't see a living thing under there. Unfortunately, I did see where rain water is collecting under the house due to it sitting on a site where the slope directs it towards the house. I have to figure out how to keep it from getting under there or how to get it out ASAP. I think I am going to tackle this is sections and go with the unfaced insulation between the studs and foam board to hold it up. I think me and the critters are going to be close for a while. At least it should be cool under there in the summer.
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Maureen
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Hi Texas,

The first thing I would do is make sure that you have no more water flowing under the home. This might take drainage around the home first. There are several ways to achieve this.

Next, I'd tackle the plumbing. If it's as bad as you say, I'd recommend replacing that with pex.

Then get your ducts repaired!

You can replace the sub floors at any point. But yes, this will be a very long and pricey project!

After everything is repaired and replaced, then you can go ahead and re-insulate and replace the belly material.

I'm sure others will have more advice for you!

Maureen 8)
Never discourage anyone...who continually makes progress, no matter how slow.
'Plato'
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