Sunline RV Forum
Sunline User Photos

Go Back   Sunline Coach Owner's Club > Technical Forums > Modifications
Click Here to Login

Join Sunline Club Forums Today

Thread Tools Search this Thread Display Modes
Old 02-25-2009, 08:32 AM   #1
Senior Member
Join Date: Mar 2007
Location: Pennsylvania
Posts: 117
SUN #212

It's almost time! Fred and I will unwinterize for our trip to Wrestling Nationals in St. Louis in March. What we would like to do before then (if the weather permits) is to winterize the underside of the camper. Last year it was a bit nippy and we plan to do more extended season camping in general. Even in the summer it will help to keep us cooler in Va Beach, plus may-be, may-be keep some insects out.
We were thinking about using some fiberglass insulation, then the very thin fiberboard and attach it all using either duct tape, glue and ties. Not real sure, but thought I'd throw out the question and see what the group may have to say. Thanks!!!
P.S. Fred just told me he has talked with our mechanic about using their huge bay to work on the camper, so weather has been taken out as a factor!

2006 T2553, 2010 Dodge Ram 1500 TRX
Tekonsha P3 Brake Controller
janetpowell is offline   Reply With Quote
Old 02-25-2009, 10:51 AM   #2
Senior Member
Steve Collins's Avatar
Join Date: Apr 2007
Location: New York
Posts: 1,846
SUN #264
Steve Collins is an unknown quantity at this point
Fiberboard is probably not a very good choice. No matter how well you paint it, it will still absorb water and fall apart very quickly. Just pull the trailer down the road once in a gentle rain, and the fiberboard will begin to disentegrate.

A much better choice is corrugated plastic panels. They look like 1/4" thick cardboard, but are made out of a rugged plastic and will last for years. If I am not mistaken, it is even used by some RV manufacturers to enclose the underbellies of trailers for their four season packages. I've seen it in black and white, but don't know about other colors.

Now, where to get it? I know that sign shops use a lot of that material now. It has pretty much completely replaced cardboard as the material of choice for political yard signs and many more applications.

The manufacturers use screws into the trailer to hold the sheets in place.

I'd check with a sign shop first, and see if they can get if for you in 4'x8' sheets at a reasonable price.

Fiberglass insulation absorbs moisture, even when not exposed direct water sources. When it is wet, it loses all of its insulating properties and becomes a breeding ground for mold, mildew, and rust on your trailer frame. Since it will be enclosed, it won't dry out.

A better choice is the rigid blue foam insulating material available at your local home improvement center. It won't absorb moisture. It comes in varying thicknesses, and can be cut very easily with a small hand saw. It is usually sold in 8' lengths. If you bought a sheet of 1.5" thick material, you could easily double or triple thickness it in some places under your rig, and in others (like the bottom side of a holding tank), use a single thickness.


'12 F250 4x4 Super Duty PowerStroke 6.7 diesel
2011 to present: '11 Cougar 326MKS
1999 to 2011: '99 Sunline T-2453
SUN264 * Amateur Radio kd2iat monitoring 146.52
Steve Collins is offline   Reply With Quote
Old 02-25-2009, 12:27 PM   #3
Senior Member
Join Date: Mar 2007
Location: Pennsylvania
Posts: 117
SUN #212

Thanks for the reply! We'll call it plan B and ditch plan A. The main reason I posted in the forum was I knew people would have experience. Thanks again!
2006 T2553, 2010 Dodge Ram 1500 TRX
Tekonsha P3 Brake Controller
janetpowell is offline   Reply With Quote
Old 02-25-2009, 12:33 PM   #4
Tweety's Avatar
Join Date: Dec 2006
Location: Pennsylvania
Posts: 2,248
SUN #128
We had a tear in our black fabric underbelly stuff. The duct tape came of between Reading and Lancaster
Lance 1475 "Snoopy"
2012 GMC Sierra 3500HD 4x4 D/A
2012 Arctic Fox 30U, SUNLINES - 2006 2753 "Tweety", 2007 QUE "QUEtSE", 2364, 1660
Tweety is offline   Reply With Quote
Old 02-25-2009, 02:31 PM   #5
Senior Member
Join Date: Jun 2007
Location: New Hampshire
Posts: 1,025
SUN #292
Honda03842 is an unknown quantity at this point
Interesting posting

Interesting posting, I hadn't thought about our underbelly before.

The underbelly of our 1982 Sunline is Aluminum from edge to edge except for the gray tank. I had not given it a thought until I crawled under a new rig recently that had something that look liked corrugated cardboard but was somekind of corragated plastic, plastic but rather flimsy.

We have attached blue foam to the front of our gray tank to protect it from stones on the Labrador Highway. It doesn't seem to absorb water but has taken a lot of hits from stones in it's role of protector. I used one of the construction mastics to attach our foam and it seems it will be there forever.

As to increasing the ability to withstand cold weather I would bet most heat goes out thru the windows, and by a wide margin. Thermopane windows do make a difference in our motorhome compared to the trailer.

I would equally assume that the vents are another major heat loss item.

In our cold weather travels in the trailer we have never had the gray tank freeze, at least not so we'd notice it. We never have the heat on at night except the electric blanket, even when it's below freezing outside. Though it would be very easy to insulate our gray tank it hasn't seemed necessary. AS well the water tank and the black tanks are internal to the rig and I can't imagine them freezing.

As to bugs, we are now in Florida, the very first day we had these micro ants walking allover the counters. I bought some general bug spray and sprayed the wheels, hoses and cable and nary a bug since then.

WHile on the topic of freezing, we've never had a battery freeze. When we leave a rig home for the winter we always keep them plugged in allowing the converter to keep them charged. As far as I know they've never freezed.

Good Travels to all,

Norm and Ginny Milliard
1982 Sunline 15.5 SB
2004 Honda CRV

Honda03842 is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Winterization mod EMD_Driver Modifications 1 01-25-2010 09:35 PM


This website is not affiliated with or endorsed by Sunline RV or any of its affiliates. This is an independent, unofficial site.

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:40 PM.