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Needs some advice concerning insulating under a mobile home

Needs some advice concerning insulating under a mobile home


  #1  
Old 10-17-15, 06:54 AM
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Needs some advice concerning insulating under a mobile home

Hello all, I have a double wide trailer and years ago the black vapor barrier ( I believe that's what it is). It looks almost exactly like that weed guard fabric. Anyway, most of it has fallen down over the years and has exposed the insulation, which is in pretty rough shape. I know some of the heat ducts also have came unhooked as we don't have heat coming out of all of the registers. What should I do? Maybe cut off all the black fabric so I can see what is going on, figure out what duct work needs replaced/fixed, insulate in between the joists, then put the black fabric stuff back over the insulation? Do I need this black fabric and where do I buy it as I have never seen it before? Thanks for your help!
 
  #2  
Old 10-17-15, 07:53 AM
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If it is within your budget, I would remove the insulation and "barrier" and have at least an inch or two of closed cell foam sprayed to the bottom of the assembly. My out can add additional fibrous insulation beneath that and then install a new air barrier material but a rigid foam sheathing on the underside of the joists would be a better approach. This gives you a measure of insulation over the entire framing assembly as well as the air barrier.

If you cannot afford the sprayed foam, use the fibrous insulation, (rock wool would be best) and then a rigid foam like "Thermax" beneath that to provide the other features mentioned above.

The ductwork should all be insulated as well and providing a wind skirt around the structure is , of course, advisable.
 
  #3  
Old 10-17-15, 08:14 AM
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Thanks Calvert. I may try to use the fibrous insulation, then put the rigid foam over it as you said. I'm sure the spray foam would be the best idea, but I imagine it's rather expensive. Although, I have no idea how much it would costs to have it sprayed under a double wide as you suggested. Thanks again! Jack
 
  #4  
Old 10-17-15, 08:44 AM
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That tarp like material is called the belly pan and serves as an air barrier to protect the insulation above. They make a special tape to repair it.

Although I grew up in a mobile home (they were them trailers back then) I have avoided studying or working on them in my energy business as they do things a bit differently. We have some pros here who are far more familiar with them than myself.

But, from a general insulation approach, I would recommend opening up as little as possible of the existing belly. Access the disconnected ducts, reconnect and air seal them and any other connections you can find. At a minimum use s good foil tape or use duct mastic (messy) possible with a fiber mesh. The messy part makes me lean towards the foil tape.

A trick: When applying foil faced tape over the top of a difficult to reach duct, peel back about half of the foil covering. Attach the exposed part as high as you can with the covering headed over the top. Feed that covering over to where you can reach it and as you pull it will peel away and leave the tape right where you want it.

As for insulation, be neat, as every opening you leave will increase the air circulation and heat loss.

Now the pros are welcome to correct me as needed .

Best,
Bud
 
  #5  
Old 10-18-15, 10:03 AM
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Thanks for the advice Bud! I appreciate it!
 
  #6  
Old 10-23-15, 01:42 PM
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Bud, I noticed most of my insulation is just hanging down on this belly pan and isn't close to the floor. Any ideas how I should remedy this or should I just staple some fibrous insulation in between the floor joists in these spots? Thanks as always! Jack
 
  #7  
Old 10-23-15, 02:53 PM
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Unfortunately I'm not that familiar with mobile home construction. Let's see if one of the pros is better equipped to answer.

Bud
 
 

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