To insulate or not to insulate

Foil bubble wrap is now up to R-8. Talk to the local air conditioner installer or parts house, They might sell it to you with the tape to properly install it.
It also makes for a good material to cover windows to darken your bedroom and cut down on heat from the sun but be carefull on where and how it is used.
Bob owner of a HVAC service/contracting company.

Agesilaus,

No manufacturer uses non-aluminum both sides faced type of bubble wrap for insulating their RV's. Your post was totally out of place if referring to RV insulation construction. This thread is in the 5th wheel section of an RV forum, not what to use in a shipping package for a filler.

Yes, I do know a lot about foil bubble wrap and it's properties and many on the forum know it. I'm not going into details again as I've done it dozens of times already and enough is enough! Maybe you should look the various foil bubble wraps up for yourself or go where they are sold and read the labels and installation instructions. Yes, having more than 3/4" dead air space on either side of the foil bubble wrap does further increase it's effectiveness but I merely gave the min. The dead air space can be filled with spun glass which is not faced or just left empty and virtually the same R-value is achieved.

Astro Foil was the original patented foil bubble wrap and was developed for NASA over 50 years ago for use in our spacecraft. Was restricted for being sold to the public until about the early 90's. Extremely light in weight and very effective in thermal/reflective properties. Reflectix is a johnny come lately knock off, not as effective, but is much cheaper in price. You get what you pay for and not more!

2 sided Foil surfaced closed cell foam board will have a slightly higher R-value and also has the reflective properties for the same thickness if there's not gaps around the edges to leak air but what manufacturer uses it? Only Lance Camper fits their unsurfaced foam board so tightly that there's no air leak gaps at all and the CNC machines used cost them millions of dollars. Go watch the walls, floors, and ceilings using form board construction at any other RV manufacturer especially TT's, MH's, 5th wheels and report back about how many air gaps you seen and how poorly the cavities are filled.

If you mean Reflextrix I have used it but it is not more effective than foam board. If you have data showing otherwise please show it. Your original msg made it look like you were just talking about packing type bubble wrap you did not specify the aluminized material.

Agesilaus,

Sir, you apparently do not know how foil bubble wrap is supposed to be used/installed. Needs a 3/4" inch dead air space minimum and then it's extremely effective and equal to the same space as if filled with foam board or spun fiberglass in R-value increase. Read the specs and instructions along with the results of most of the independent thermal tests. Why do you think the manufacturers use it or offer it as an option. Not only does proper installation provide equal R-values but also gives excellent reflective properties and is a very efficient vapor barrier too.

Not all RV manufacturers install foil bubble wrap correctly and therefore do not gets it's benefits to pass on to the purchaser. Don't knock a product because you don't know it's actual documented test after test results!

Garyl53 wrote:
Where do you install the 2 inch foam board. Can you just slide it in on top of the coroplast but below the tanks?

Yes or you can stick it with adhesive to the underside of the floor.

Where do you install the 2 inch foam board. Can you just slide it in on top of the coroplast but below the tanks?

agesilaus wrote:
Insulation also helps the air conditioning keep cool air inside the camper. Use 2 inch foam board.

X2, provides better, per inch of insulation than the fiberglass insulation, and should stand up to water better!

TakingThe5th wrote:
My underbelly used some insulating bubble wrap. The big box stores carry it and it's simple to install. Pick up some larger fender washers while you are there to cover your enlarged screw holes. Also fresh screws make the work easier.

How would bubble wrap be any better than a closed air volume. Sounds like the manufacturer was being cheap:

"This R-1 product can be used to make Halloween costumes, but should never be used as insulation. Foil-faced bubble wrap is a thin product that comes in a roll. Its R-value is dismally low. Most brands of foil-faced bubble wrap are only 3/8 inch thick or less, and have an R-value of only 1.0 or 1.1."

My underbelly used some insulating bubble wrap. The big box stores carry it and it's simple to install. Pick up some larger fender washers while you are there to cover your enlarged screw holes. Also fresh screws make the work easier.

When I had a similar problem with our travel trailer I sealed the underside of the deck with a waterproofing paint. I then glued foamboard to the deck. I would keep the vents open, for the next owners if nothing else.