Mobile Home questions


Old 08-06-11, 08:14 AM
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Join Date: May 2002
Location: ny
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Mobile Home questions

I have recently begun renovating a 1972? MH. It is 12x72 flat roofed. I have a few questions which hopefully you all can help with:

1) What type, thickness, r-value insulation is typically used in the ceilings? It is unfaced fiberglass, but i don't know what i need to replace it with)

2) I have read about insulation beneath the MH and i understand that many people use tarps to hold the insulation up. Would using housewrap be a better option? (i have some left over from when i resided my home)

3) The home is really a summer gettaway/ hunting site. So most of the time the windows are closed, electric shut down, no constant temp inside. I would like to replace the carpets. Would laminate flooring work under these conditions or would they warp/bow?

4) Lastly...for the plumbing in MH standard sizes ...1/2 in 3/4, etc that can be found in any home inprovement store?

I appreciate any help. I know that many of these questions belong in other forums, but it was easier that posting 5 diff posts. If needed, i will do that later. Also, because the MH is 45 mins from closest supply store, i am trying to self educate to eliminate too many trips.
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Old 08-06-11, 08:45 AM
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#1 - I don't know but it's always insufficient. The problem you run into is if you fill the ceiling cavity with insulation, there is no way for the heat build up in there to escape thru the little roof vents. IMO the best solution is to build a roof over complete with an attic space. You can then fill the ceiling space with insulation, even add more over the roof if needed. 2nd best would be one of those MH roof overs that use foam over the roof and a new aluminum roof over the foam. I don't know a lot about them but they were real popular when I lived in fla.

#2 - the main thing is to hold the insulation up and keep critters out. I've always used tar paper to replace failing or missing belly wrap. I would assume your leftover house wrap would be ok. The biggest issues will be dealing with the block piers and the metal beams.

#3 - I don't know but I too would rather have wood or laminate than carpet. Maybe parquet would be a good option.

#4 - most MHs from that era used a mixture of galvanized pipe [normally 1/2"] and copper tubing. Sometimes the ends of the tubing are specialized sizes and will require an adapter or two to make them fit new faucets. I've always replaced it with cpvc.... but I'm not a plumber and cpvc is easy to work with
Old 08-06-11, 10:35 AM
Join Date: Aug 2009
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For under the mobile home, consider rigid foam board. You get more R-value per inch. It is also an air barrier. If you put fiberglass batts under there, any airflow will destroy it's r-value.
Old 08-06-11, 10:49 AM
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Just to add, any insulation foam or batt...will probably need to be covered with something. Rodents (mice, chipmunks, squirrels, etc) of all types love to nest in that.

Oh...guess mark touched on that...well, never hurts to emphasize...
Old 08-06-11, 10:59 AM
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As far as the piping goes Mark gave you a big clue!
Mobile homes use copper tubing and copper tubing is not sized the same way pipe is.
Pipe is sized by inside diameter and tubing is sized by outside diameter.

Where the confusion comes in is when plumbers come in and mess everything up!
Because of the origins of the plumbing trade inside diameter is historically what sizes are used.
Trades other than plumbing that work mostly with copper refer to all copper as tubing and are sized according to outside diameter.
There is no difference in the tubing, only what it is referred to as.

Common plumbing tubing would be called 1/2", 3/4" and so on but is actually 5/8" and 7/8" in outside diameter and what its tubing size is.
So, when dealing with a mobile home, the companies building them work within a wider range of sizes.
Folks coming across these sizes and most of the retail outlets selling fittings refer to them as oddball sizes but nothing is further than the truth.
What is true is that most places that sell plumbing parts don't get much call for them so don't stock them or know what they even are.

So what you need to do when planning your plumbing repairs is be aware of this possibility.
The pipe threads will be standard but the tubing might not be common.
If you were to find a short piece of 1/2(5/8) or 3/4(7/8) and take a small caliper you would be able to figure out exactly what to do.
Because these fittings and tubing are not usually stocked you might be better off adapting to common sizes.
Old 08-06-11, 12:21 PM
Join Date: Aug 2009
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Not that I own a mobile home, but I don't quite understand what you mean here. Are you saying they are both the same size but their names are different? I know when it comes to piping, the outside diameter is what it is manufactured to and the inside diameter is what varies. A 1/2" inside diameter pipe isn't actually half inch. It will vary depending on the wall thickness. The reason they manufacture to the outside diameter is to make sure all pipe will mate with the same fittings.
Old 08-06-11, 12:36 PM
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When it comes to copper, there are two names for the same thing.
Steel pipe has for a couple of hundred years been labelled as to the inside diameter of standard wall pipe.
The outside dimension is always the same no matter what wall thickness you have.
This is why it is so confusing when you take a tape measure and try to measure the inside diameter of steel pipe.
It will only match its namesake when it is standard wall pipe.

Copper is where it gets messed up.
Some people call rigid copper "copper pipe" but it is not.
It is called "copper tubing", either "hard drawn" for rigid copper or "soft drawn" for copper in a roll.

What I have seen a lot of in mobile homes is 3/4" tubing size which measures 3/4" od.
It is actually an upgrade from 5/8" tubing size or 1/2" "copper pipe".
People like the high flow rate in their MH but get confused when they have to repair it.
Honestly, it really doesn't matter !
It only gets a little cloudy when the kid at the parts store says; "Golly gee! you got some of that weird copper there!"

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