Tuesday, May 24, 2022


Ask Dave: Renovating 2006 Holiday Rambler – Does it need a moisture barrier?

Dear Dave,
I’m in the process of doing a complete makeover on a 2006 Holiday Rambler Admiral before hitting the road for an extended period. The interior walls and ceiling were a bit dated. While it is opened up, I plan on improving the insulation. The exterior is fiberglass end caps with aluminum walls and a fiberglass roof. The present insulation consists of fiberglass and styrofoam. Does it require a vapor barrier when reinsulating? I do not see one now unless that is the function of the styrofoam, as well as insulating. —Gary Vernon
P.S. I’m very disappointed in how difficult/impossible it is to get any information from manufacturers!

Dear Gary,
Holiday Rambler has had several owners over the past many years including Harley-Davidson way back in the late 1980s. As the brand shut down, sat dormant, and then the name got purchased, unfortunately, there was very little documentation that was archived or traveled along with the name. This is typical for companies that close such as National RV, Monaco, and others. 2008-2011 was probably the worst of times, as the industry was at an all-time low and many companies went out of business.

Holiday Rambler walls

If memory serves me correctly, the aluminum exterior walls of your 2006 Holiday Rambler Admiral are fastened with rivets rather than adhesive. Is this correct? And I do believe your interior walls are a thin plywood called Luaun with a wallpaper-type interior skin, right? If so, the panel will be hard to pull apart from the block foam and aluminum framework without tearing either the Luaun or the block foam. Then you will have an issue getting the new paneling fastened. Most renovators either paint the existing walls or apply stick-on wallpaper. I don’t know of any RV manufacturer that used a vapor barrier. However, I think it would be a good idea.

I recommend researching Vintage Camper Trailer magazine. They specialize in renovating vintage units and might be familiar with the HR history. If you do get the interior paneling off, I would suggest replacing any loose-fill insulation with block foam. Most manufacturers use the 2# white beadboard, as the adhesive holds better. Winnebago used the Dow Blue Board for awhile but found the thickness was not consistent and the slick surface caused delamination.

One thing I have witnessed in renovations is fastening the interior paneling to the framework using flat head screws in line. Then they’re covered with a paneling seam tape—which is a decorative tape used to cover seams between two panel edges.

Read more from Dave here

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.


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Steve Hericks
4 months ago

6) Don’t glue the insulation to the back of the aluminum skin. The sun heated temperature of the skin will destroy any bond the glue will have (over a short time). The interior skin would be best glued and fastened to the framing. Glue choice will be some kind of ‘caulk tube’ applied material that will be able to be vertical without running and have an ‘open time’ long enough to not ‘skin over’ before you get the wallboard up. I recommend having help to do this so it can be done quickly.
7) Securing the wallboard to the tube frame will need to spread the glue and close the joint. It can be done with either screws or blind rivets. Spacing needs to be pretty close because the thin wallboard will flex a lot This is going to leave a very prominent, visible pattern that there is no practical way to disguise (well). Small (1/8″ or smaller) broad head rivets are likely best (shallowest and broadest heads). Do not use countersunk head rivets as they have an inadequate grip on the luan.

RV Staff(@rvstaff)
4 months ago
Reply to  Steve Hericks

Thank you for all of your very knowledgeable information, Steve! We, and our RVtravel.com readers, appreciate it very much! Have a great day. 😀 –Diane

Steve Hericks
4 months ago

3) The aluminum skin is probably not part of the glue sandwich so when the insulation is removed, should be clean.
4) 1.5lb EPS is poor insulation having an R-value of ~3/inch. It is far better to use Polyisocyanurate (aka urethane foam faced with foil on both sides which is not very structurally strong) or extruded polystyrene (XPS) with an R-value of ~6.5/inch (which is stronger). For walls, 1.5lb/cuft is adequate. Floors should have 2.5lb/cuft densities.
5) Gluing it back together as it was is impossible since urethane glue (‘Gorilla glue’) is a moisture activated and foams when it cures, requiring the wall to be held in a vacuum clamp.

Steve Hericks
4 months ago

I’m a former plant engineer for Safari Motor Coaches and built their wall lamination system. SMC walls consist of an aluminum outer skin riveted to 1-1/2″ square tube framing with 1.5lb/cuft density expanded polystyrene foam and interior with pre-papered 1/8″ luan, all glued with urethane glue. We previously used sprayed contact to assemble the walls. It sounds like a similar construction.
1) No vapor barrier is required since the aluminum/fiberglass outer layer is impermeable to water.
2) Wall disassembly (this is an incredibly big job); removing the interior walls, you will find that the luan wallboard and EPS foam are glued in and you will need destroy them in order to remove them. I am assuming this wall is glue-laminated which it almost certainly is or it would not have lasted long. Once the wallboard is removed, the EPS will be torn up. Removing it is not difficult BUT sharp tools that make contact with the outer skin, can transfer scrape marks through the wall.

Bob p
4 months ago

He has a handful of headaches ahead, wishing him good luck. For a non professional to tackle a job like that he’ll need all the good luck he can get.