insulating underbelly

[tmarshall]

I just dropped the underbelly yesterday and added 3 1/2" of encapsulated R-13 fiberglass insulation. I started to pack it around the holding tanks, but thought that the space is so tight that I don't want to restrict air flow to the holding tanks from the furnace. I went ahead and put the insulation in the back half of the rig where there are no holding tanks or water lines (2004 3670RL). I figured that reducing the air space back there would help to concentrate the heat by the water lines and the holding tanks. I did not place any insulation where the slide mechanisms are. Does anybody have any experience with adding insulation like this? Do you think that I am wasting my time or will this help?

I am about half done now. I am going to drop the belly again next weekend and finsih putting foam tube insulation on the water lines and elevate them off the belly pan to allow heat to flow around the pipes. I removed the low point drains and took the cap off the bottom of the drain tub and put it on the T-connector in the belly. I made an access hole so I can put the low point drains back in place when I need to with little hassle.

Please tell me your experiences with adding insulation and if it helped or actually hurt the performance of the RV. Thanks.

Tim Marshall
2004 3670RL Montana
2002 F-350 powerstroke diesel

[old turbo]

Tim, I have thought about the underbelly covers and what is under it. I have just been toooo lazy to get at it. It sounds from your discription its just a big void , with tanks and pipes. I may go with a non fiberglass insulation from Menards Building Supply.I am goig to cut foam board and put it under the floor of my toilet and shower area. This is a cold toes area, wife gripes about it all the time. Can get at this in my basement area. I have sealed up some cracks and gaps with low rise spray foam. Can find lots of places to use up a whole can. ARCTIC PACKAGE?????. My idea of arctic package must be different than Keystones. Whats behind the nose cone, besides the closet wall?

[Illini Trekker]

Hi Tim, I have also been there done that. I did a couple of things you might think about doing. One lap the insulation up on the steel frame, steel has 0 R factor. I have a 2955RL I'm guessing all three tanks are in the front of trailer, mine are. Just to the aft (rear) side of the tanks I created a air dam with the insulation to block or help stop the ducked air flow from flowing the length of the trailer. This put the majority of that heat in the area that needed it. Now I must say that ALL the pipes are wrapped and have heat tapes on them! Also as Ozz has stated in another post and I wish I would have done was to wrap the wires two protect them and try to get them in some organized fashion. It's quite the job but one that will pay off. Tighten all those water line while you're under there, that alone is a big safety concern!


The hunt makes the find that much sweeter!
Dennis and Debbie
05 Montana 2955RL Spruce Decor
2005 GMC 2500HD D/A CC SB Dark Metallic Blue
18k Reese Signature Slide Underbed Mount
Access Lorado Cover
Prodigy
Weston Nerf
Ride-Rite

[tmarshall]

I bought precut pieces of R-13 insulation that are 7'-9" long and 15" wide. These pieces are perfect for insulating the belly and insulating the 10" I-beams on each side of the coach. That is a great idea about creating an air dam to trap the air by the tanks (yes, all my tanks and water lines are up front). Now that I think about it that is exactly what I have done. I have to get back in there and better secure some of the insulation around the slideout mechanisms. Illini trekker, what did you do around the slide out arms? I duct taped the insulation to the nearest cross member so it will not slide into the mechanism. I think I will secure it better next weekend. I am not planning on heat taping my water lines down in the belly. I thought about it from your last thread on insulation about a month ago, but I figure I will try it with just the foam tubes and propping the pipes off the bell for air flow this first winter.

OldTurbo: The belly area is just a 10" empty space with cross members, wiring, plumbing, and tanks. I did not see what is behind the closet, but I imagine it is an aluminum frame with insulation and and extra sturdy fiberglass end cap. I only pulled off the panels in the belly and not under the bedroom in the 5th wheel part. The arctic insulation package is just 1 sheet of reflectix astro foil insulation that sits on top of the plastic belly panels. The astro foil adds and R-value of about 6-7. The added R-value all depends on how it is installed. I still have a lot of gaps betweent he steel frame and the plastic belly panels too so I am going to seal those up with gorilla tape or something less messy. Either way those gaps will get sealed.

Tim Marshall
2004 3670RL Montana
2002 F-350 powerstroke diesel

[Illini Trekker]

Hi Tim Today Monty project was to put a hinge on the broken wire slide support and now two additional tail lights mounted under the rear cap.

Has far as the slide works, on mine I just used 1 1/2" foil backed insulation. On yours the duct tape, as you know will not hold long? What do you think about creating a boarder using aluminum, the kind used on the fascia of a house, the kind that covers a 2x4? Get some self tapping screws and just drill up through the black panels to hold the fascia in place.

I also need to seal the gaps the in the black panels. The gorilla tape is the fast easy way to go but I still find the need to get inside the belly to do the add-ons. Rich as used the gorilla tape on his Monty, time will tell if that's working for him? But when I went back with the self tapping bolds that hold the panels in place I used a fender washer with the bolts, little more surface grab.

Do you plan to use the trail this winter? I work out of mine year round and use to in the off times to travel with gives me a Plus Plus!


The hunt makes the find that much sweeter!
Dennis and Debbie
05 Montana 2955RL Spruce Decor
2005 GMC 2500HD D/A CC SB Dark Metallic Blue
18k Reese Signature Slide Underbed Mount
Access Lorado Cover
Prodigy
Weston Nerf
Ride-Rite

[richfaa]

The report is still out on the gorilla tape.I have found that it has loosened in some some spots. My evaluation is that there was some dirt or grease on the frame or underbelly in places and it will not stick for long. I think the best solution is to fill those gaps with that foamy stuff .The reason I did not do that was the hassel that would be involved if you had to drop the underbelly..We have not given up on the gorilla tape..it is doing Ok in 90% of the area..

Rich& Helen N.Ridgeville,Ohio.

F-350SD, Lariat, V-10,4:30 Diff, tow command Long bed, Crew Cab Dually, 06 3400RL
Mor-Ryde Pin Box

[Illini Trekker]

Thanks Rich for the gorilla tape update!! I like the idea of using that angle iron with the holes pre-drilled in it. The only down fall is the cost, and hitting it with something not quite as hard as it is (like my head).


The hunt makes the find that much sweeter!
Dennis and Debbie
05 Montana 2955RL Spruce Decor
2005 GMC 2500HD D/A CC SB Dark Metallic Blue
18k Reese Signature Slide Underbed Mount
Access Lorado Cover
Prodigy
Weston Nerf
Ride-Rite

[tmarshall]

Dennis,

I too work construction and am actually on the project administration side of it. I live in the monty full time and if there are no winter projects, I have to spend the winter in the office in Denver. So, I have to expect the worse and get this thing so it won't freeze up.

That is an excellent idea about the aluminum form for the insulation. That may be the best idea yet. I just had a thought come to mind about "sewing" hemp through the insulation and looping it around the cross frame to hold it in place. The loops would be about 3" in from the edge of the fiberglass insulation and have about 3" in-between the loops along the length of the insulation. I know this will work, but will the hemp cord rip through the insulation and work itself free. The verdict is still out on that one. The aluminum frame would never move and I would never wonder. I could just look to make sure the screws in the belly are in place and I'll know the aluminum is still there. Maybe I could use both techniques... Keep the good ideas rolling. I love it!

I got the idea about the gorilla tape from Rich a while back. I originally bought the foam insulation, but have not used it yet. I was also thinking about attaching some office binder clips (chip clips) to hold the plastic panels to the frame.

Tim Marshall
2004 3670RL Montana
2002 F-350 powerstroke diesel

[Illini Trekker]

Hey Tim, I've found when I would try to fit a wrinkle in metal the wrinkle just moves! It will be hard to flatten out that belly plastic with clips? The angle I fell is the way to go if you don't want to fill the gaps.

When you get done with the belly start on the basement



I used those plastic washers that roofer use to hold down there felt paper, but changed out the nail for screws to match the thickness of the foam board to hold it up. See-Ya


The hunt makes the find that much sweeter!
Dennis and Debbie
05 Montana 2955RL Spruce Decor
2005 GMC 2500HD D/A CC SB Dark Metallic Blue
18k Reese Signature Slide Underbed Mount
Access Lorado Cover
Prodigy
Weston Nerf
Ride-Rite

[sreigle]

tim, I'm not real sure how much good the extra insulation will do. I've had the belly open when the furnace was pumping and the outside temperature well below freezing and the furnace puts plenty of heat down there. However, insulation certainly won't hurt anything and might let you run the furnace a bit lower. We can get to zero without freezing, although we have done some other modifications to get to that point (with the one we just traded in). The pipe insulation is a good idea. For one, it helps keep hot water hotter when it arrives at the faucet.

Yours probably has the low point drains hanging below the belly. Those will be the first to freeze. Ours froze at 22F. I insulated them and got to 17F. I heat taped them, then covered with foam pipe insulation, then wrapped some insulation around that then duct taped the whole thing. With the heat tape plugged in we could get down to at least zero without them freezing. Actually, we got to five below and they didn't freeze.

See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'07 3400RL
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4

Our RV Travels (now Firefox-compatible)

[tmarshall]

Steve,

I cut an access panel in the belly by the low point drains and I took the low tubes off and used the cap on the bottom to cap off the T. I ordered a three way valve from pexconnection.com and will install that in place of the "T" so I can open the valve when I want to use the low point drains. All the other times I don't need them I will keep the valve closed. I figure it is the same as the new models with the valve in a heated compartment. It is just a bit more inconvenient to get to I will by plastic or a sheet of something else and screw it to the other underbelly panels so I have a nice access door that will easily come off.

Tim Marshall
2004 3670RL Montana
2002 F-350 powerstroke diesel

[richfaa]

As with any tape you need to be really sure that the surface is clean. Mine was new when I applied the Gorilla tape and it did not look like there was oil or grease on the frame or underbelly. Think the gorilla tape will only work on a new camper that is free from dirt or any oily residue. I treated a couple of spots where it had come loose by cleaning it with alcohol and re applying the tape....we shall see..

Rich& Helen N.Ridgeville,Ohio.

F-350SD, Lariat, V-10,4:30 Diff, tow command Long bed, Crew Cab Dually, 06 3400RL
Mor-Ryde Pin Box

[sreigle]

quote:Originally posted by tmarshall

Steve,

I cut an access panel in the belly by the low point drains and I took the low tubes off and used the cap on the bottom to cap off the T. I ordered a three way valve from pexconnection.com and will install that in place of the "T" so I can open the valve when I want to use the low point drains. All the other times I don't need them I will keep the valve closed. I figure it is the same as the new models with the valve in a heated compartment. It is just a bit more inconvenient to get to I will by plastic or a sheet of something else and screw it to the other underbelly panels so I have a nice access door that will easily come off.

Excellent idea, Tim. The only time you really need the low point drains is when winterizing and it sounds like you're not going to be doing that anyhow.

See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'07 3400RL
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4

Our RV Travels (now Firefox-compatible)

[Mudchief]

When cold weather comes along I drain the water then back fill the low point drains with the pink rv antifreeze. When you connect back up to water there is not place for the antifreeze to go so it stays in the low point drains. I have camped in below zero temperature without a problem.

Dennis & Linda
05 GMC 2500HD Duramax CC
Pullrite Superglide
05 Mountaineer 329RLS
[IMGhttp://i3.tinypic.com/znkncy.jpg[/IMG]

[tmarshall]

Dennis,

How do you backfill the low point drains with RV antifreeze? Do you completely fill all water lines with the antifreeze or do you justput a tad bit in until it fills the low point drains. This is an excellent idea. Thanks.

Tim Marshall
2004 3670RL Montana
2002 F-350 powerstroke diesel

[Mudchief]

I have a large syringe that I fill. I then remove the cap from the low point drain and inject the stuff. I put enough in so it goes up into the main water lines because you will loose some when you are trying to get the cap back on. When you connect up to the water you will flush out any that may be in the main lines. If you do a search you will find where some people have added a valve that you can open and close to make draining easy. That would also make this process a little more easy. You can also buy a small hand operated transfer pump at Walmart. and do the same thing.

Dennis & Linda
05 GMC 2500HD Duramax CC
Pullrite Superglide
05 Mountaineer 329RLS
[IMGhttp://i3.tinypic.com/znkncy.jpg[/IMG]

[Illini Trekker]

Tim with a 2" piece of flex duct off the heater to heat that big an area I think the added insulation will be a big help this winter. The holes around the slide openings can be easily plugged with the same pipe wrap you just need to remove it when you travel.

I owned a HI-LOW before the trailer and used foam pipe wrap to seal the area between the slides. You might look at doing this around the insides of your slides this winter to help create a better seal?


The hunt makes the find that much sweeter!
Dennis and Debbie
05 Montana 2955RL Spruce Decor
2005 GMC 2500HD D/A CC SB Dark Metallic Blue
18k Reese Signature Slide Underbed Mount
Access Lorado Cover
Prodigy
Weston Nerf
Ride-Rite

[sreigle]

One thing about sealing openings in the bottom is be careful not to seal the bottom so tightly the air inside has nowhere to go, thus reducing the amount of hot air the furnace can pump in there.

When I had the bellypan off the right rear corner, about the farthest away from the heat duct, I found plenty of hot air flowing. Outside temperature was mid teens, if I recall. I really don't think there's much problem there but I do think more insulation might allow running the furnace at a lower thermostat setting (i.e. running less often). In other words, I think it's good as it comes from the factory but more insulation would make it even better.

See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'07 3400RL
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4

Our RV Travels (now Firefox-compatible)

[richfaa]

Would be interested in knowing how well your underbelly is sealed around the edges, underbelly to frame.Mine had large gaps between the screws. I agree about sealing it to well. There is however plenty of gaps around the springs and jack stands to allow for ventilation. We are not concerned about cold weather but more so with water and road grime working its way up into the underbelly..how did your 3295 hold up in that respect???

Rich& Helen N.Ridgeville,Ohio.

F-350SD, Lariat, V-10,4:30 Diff, tow command Long bed, Crew Cab Dually, 06 3400RL
Mor-Ryde Pin Box

[Illini Trekker]

There are really on good ways to make a seal at the big slide openings which will let a lot of air out of the belly. When adding new brake and signal lights under the rear of the trailer last week I also discovered that the rear cap you could say is getting heated as it is open to the underbelly!

Rich I plain on cutting some small peaces of tin to the size around the springs an pipe openings. With the tin and a little caulk this will close those up.


The hunt makes the find that much sweeter!
Dennis and Debbie
05 Montana 2955RL Spruce Decor
2005 GMC 2500HD D/A CC SB Dark Metallic Blue
18k Reese Signature Slide Underbed Mount
Access Lorado Cover
Prodigy
Weston Nerf
Ride-Rite