Questions & answers about mobile home & trailer insulation guide to selection, installation, inspection, troubleshooting, & improvement:

This article series gives the steps to reduce heating, cooling, and electricity costs for manufactured homes, mobile homes or doublewides / trailers. While you might think that insulating is the top priority it might not be.

Mobile Home & Trailer Home Insulation & Ventilation FAQs

The photo at page top illustrates a manufactured home that has no insulation.

In fact those muddy streaks on the steel center beam tell us that this home was indeed driven down a wet highway.

[Click to enlarge any image]

On 2019-04-25 by Dale - what the r-value probably is in a 1986 mobile home?

anyone have an idea of what the r-value probably is in a 1986 mobile home?
Thanks

 

On 2019-04-26 by (mod) - what is the R-Value of Insulation in an Older Mobile Home & What are Current Manufactured Home R-Values?

Dale:

First let's measure or estimate the thickness of your home's wall cavities and ceiling space.

We can inspect through an opening to confirm the insulation material probably used (such as fiberglass) - often one can drill a small hole - in an unobtrusive place like a closet wall and ceiling, taking care to stay away from wiring and ductwork, and where an ugly patch won't offend anyone.

Older mobile homes were often built with 2x2 or 2x3 walls, giving about a 2" wall cavity.

To compare insulating material R-values of fiberglass in various forms as well as other insulating materials, see

our TABLE OF PROPERTIES OF INSULATING MATERIALS

Now let's pretend we have X-ray vision and can see your actual home (in some country and city and by some manufacturer) and that we see the walls of your home are built as follow - I AM MAKING THIS UP

Typical Older Mobile Home Wall R-Value

1/2" fiberboard insulating board sheathing on the wall exterior - about R 1.3 - FIBERBOARD at inspectapedia.com/insulation/Insulation-Values-Table.php#Fiberboard

1 1/2" wall cavities filled with fiberglass - about R 4.5 - FIBERGLASS at inspectapedia.com/insulation/Insulation-Values-Table.php#Fiberglass

1/2" drywall on the wall interiors - about R 0.5 - DRYWALL at inspectapedia.com/insulation/Insulation-Values-Table.php#Drywall

Wood paneling - not worth considering

Typical older mobile home Wall insulation R-value = (1.3 + 4.5 + 0.5) or

about R-6.3

Typical Older Mobile Home Ceiling & Roor R-Value

Older mobile home roofs were often made up to include

Metal rooftop construction & insulation

1/2" foam roof underlayment - about R 2 - FOAM INSULATION at inspectapedia.com/insulation/Insulation-Values-Table.php#Styrene

1" of fiberglass insulation in roof cavity - about R 3

3/8" or 1/2" ceiling drywall - about R 0.5

for an older mobile home total roof R-value of about ( 2+ 3 + 0.5) =

about R 5.5

Watch out: The R-values don't mean diddly if the home is leaky - air leaks will overwhelm the insulation no matter how thick it is. So your best bang for the buck in saving heating costs is to feel around for air leaks - often at windows and doors, and to seal those from the outside or inside with sealant or caulk.

Also see MOBILE HOME ENERGY ZONES for help deciding how much insulation you need.

What is the Currently-Required Insulation or R-Value for Manufactured Homes?

Take a look at the U/O Value Zone Map [shown above] giving insulation requirements (to comply with current manufactured housing codes) for the U.S. for Manufactured Housing.

Unfortunately the insulation or heat loss values are given in U-values while normal people think about R-values.

The relationship between R-value and U-value and the math of converting one to the other are given

at HEAT LOSS R U & K VALUE CALCULATION

It's rather easy - U-value is a reciprocal or 1/R-value

So if your home is in North Dakota in Zone 3 the required U-value is 0.079 and if we take the reciprocal of that to get R-value we get

1 / 0.179 = R 12.6 - that's the current required R-Value for manufactured homes

On 2019-03-11 by (mod) - replace rodent infested or wet insulation in mobile homes

The insulation, if it has been wet or rodent-infested, should be replaced. Following that your contractor will install a new belly wrap.

On 2019-03-10 by Sylvia Henry

Insulation Falling Down Under My Double Wide

My installation Is Falling Down Under the home

On 2019-02-27 by (mod) -

Sal

It sounds like a small job for a handyman. Why don't you see if you can find someone local who is willing to take a look and let me know what you told about what work is needed and we can comment further

On 2019-02-26 by Sal

I need my ventilation system cleaned out,its a big issue.I first need to repair at least one 2 ft x 2ft tear in the bottom board.I need this work done.Id like an idea of the costs for the job as well.

On 2018-11-18 by (mod) -

Re-posting a Q&A received and replied-to by private email:

Is there a “ventilation” requirement for manufactured homes. I thought that I had seen the requirement to have a window in every room for the purpose of ventilation.
- Anonymous by private email.

Reply:
The ventilation requirements are the same for manufactured homes as for stick-built homes, if you're talking about modulars.

If by manufactured homes you refer to mobile homes, singlewides, doublewides, depending on the home's design there can also be a requirement that certain windows such as at an end bedroom also be capable of opening to provide emergency egress in the event of a fire.

See manufactured home ventilation details at

MOBILE HOME INSULATION & VENTILATION

On 2018-07-23 by (mod) -

Tina,

To have space for a detailed reply to your question I will repeat it along with our reply at

MOBILE HOME INSULATION BELLY WRAP

Please take a look and let me know what questions remain. You may need to clear or refresh your browser to see the updated page.

On 2018-07-22 by (mod) -

Re-posting with corrections our 2017 reply to Jacob

Jacob,

We would need some material under the floor of a mobile home to contain blown in insulation, otherwise it's simply couldn't be installed.

Usually a woven polyethylene belly-board "insulation" is fastened to the under-side of the floor joists. However if that material is loose or insecure or torn it needs to be repaired and supported before blowing in insulation from either the home's side rim joist or through slits in the belly-board.

Take are not to cover electrical boxes, nor to fill a joist space used for HVAC air supply or return - add ducts there first.

On 2018-07-22 8 by tina wilson

what kind of insulation do I use for under the belly of my manufactured mobile home and where can I buy it ?

On 2017-09-22 by Jacob

Does blown-in insulation under a mobile home need the black plastic underbelly?

On 2017-09-17 by Randy Kuhn

We live in an early 1980s double wide "modular". I have opened both gable ends to blow in additional insulation.

After making the openings and seeing the inferior building materials and realizing the ceiling drywall is 3/8 inch thickness, I am now concerned about the additional weight from the new insulation.

Is this a wise concern or am I stressing over nothing? Should I opt for fiberglass blow in insulation as opposed to celatex type?

...

Continue reading at MOBILE HOME INSULATION BELLY WRAP or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Manufactured Home Insulation & Ventilation Articles

• CRAWL SPACE VENTILATION CODES
• HEAT LOSS R U & K VALUE CALCULATION
• HOUSEWRAP AIR & VAPOR BARRIERS
• INSULATION AIR & HEAT LEAKS
• INSULATION LOCATION - WHERE TO PUT IT
• MOBILE HOME CRAWL SPACES - how to inspect the mobile home crawl space
• MOBILE HOME ENERGY ZONES
• MOBILE HOME HEATING SYSTEMS
• MOBILE HOME INSULATION BELLY WRAP
• MOBILE HOME INSULATION & VENTILATION
• MOBILE HOME SKIRTING
• WINTERIZE A BUILDING

Suggested citation for this web page

MOBILE HOME INSULATION & VENTILATION FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to MANUFACTURED & MOBILE HOMES

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