Upgrading underbelly for colder temps

[RogerWo]

2016 Fury toy hauler. Coroplast extends from front of unit to front wall of haul area and from frame to frame. No heat ducts in underbelly. I want to extend the freezing level to at least low to mid 20's for over night stays. Suggestions appreciated. Thanks, Roger

[brad2388]

Originally Posted by RogerWo

2016 Fury toy hauler. Coroplast extends from front of unit to front wall of haul area and from frame to frame. No heat ducts in underbelly. I want to extend the freezing level to at least low to mid 20's for over night stays. Suggestions appreciated. Thanks, Roger

I debated putting fiberglass batting under there but never did.

I was afraid it would get wet and be worse off than without any.

Will be interested to see everyones take on this.

[Reverse_snowbird]

Originally Posted by RogerWo

2016 Fury toy hauler. I want to extend the freezing level to at least low to mid 20's for over night stays.

For an overnight stay, you might not need a lot of prep.

We tend not to hook up the water because we don't have a heated water hose. Also, frozen water hoses are impossible to roll up.

You may want to install tank heaters to protect your grey and black water from freezing. They are like a blanket around the tanks.

Keeping the cupboard doors open under things like the kitchen sink will help keep them warm and running the water occasionally will help keep it from freezing.

For warmth, we use a small electric heater with temperature control. Rug runners on the floor help keep the heat in and it just feels better on your feet. Some people put insulation on the windows to reduce heat loss.

Now if it's raining and turning to ice....make sure the wheels are securely chocked so you don't go sliding while sleeping.

[RogerWo]

Originally Posted by brad2388

I debated putting fiberglass batting under there but never did.

I was afraid it would get wet and be worse off than without any.

Will be interested to see everyones take on this.

I agree on the batting. Think what I am going to attempt to do is to run a aluminum flex duct from the furnace into the underbelly and make sure that the coroplast is tight. I will still have the issue of the exposed I beam which will act as a heat sink. Hopefully the flex will offset any heat loss.

[Kimber45]

foam does dot have the rv value that fiberglass does but would withstand water better. pull down the coroplast add 1/2 or 3/4 foam board and reinstall the coroplast?

[brad2388]

I was worried to about it getting in the slideout tubes going in and out.

[mmangiarelli]

You could use Rockwool batts, fire & water resistant.

[RogerWo]

When I open up the underbelly for the flex install I am going to check on the possibility of installing some closed cell foam product as suggested before. I know this is available in 3/4, 4x8 sheets with foil backing. If this can be installed laying in the inside lip of the I beam without causing a lot of changes, I will attempt it. Moisture should not really affect it. I am also going to check on the possibility of installing rigid foam on the inside wall of the I beam.

[carlsbad]

Assuming you will have power, the easiest solution is to add tank heaters and perhaps add a duct off the existing furnace to blow in the enclosed space.

[RogerWo]

Originally Posted by carlsbad

Assuming you will have power, the easiest solution is to add tank heaters and perhaps add a duct off the existing furnace to blow in the enclosed space.

Power not a problem. Generator on board. When I open it up I will check for tank heaters. Looks like a 2 inch hole was cut through floor in the furnace area. If I can access the duct area I am planning on adding a 2 inch open end flex into the belly area.

[DennisTD]

Great ideas. I have been considering this for my XLR 29HFS. Unfortunately, due to the lack of engineering, the pathetic furnace won't even heat the living space much less the underbelly.

[Wilco]

Don't forget to seal the seams and edges of the Coroplast with aluminum HVAC tape. It will keep the heated air in and water out.

[BigBear0216]

Originally Posted by RogerWo

When I open up the underbelly for the flex install I am going to check on the possibility of installing some closed cell foam product as suggested before. I know this is available in 3/4, 4x8 sheets with foil backing. If this can be installed laying in the inside lip of the I beam without causing a lot of changes, I will attempt it. Moisture should not really affect it. I am also going to check on the possibility of installing rigid foam on the inside wall of the I beam.

FWIW if you intend to insulate the underside, keep that insulation tight to the subfloor above. If you don't, that air space between the insulation and the floor will just be cold and you won't benefit from the R-value of the insulation you have just installed.

[MR.M]

I installed 2" foam board in all openings under belly cover , wrapped all tanks with the silver bubble stuff , added foam pipe insulation to all water pipes . only issues is the tank drains that are outside the underbelly they will freeze if it gets to cold

[RogerWo]

I dropped the coroplast on most of one side and was able to see most of the area in the underbelly. The plan that I am going to follow is to add 25 feet of 2 inch air duct open end with furnace heat. I will then seal the coroplast and modify / enclose and insulate the fresh water and hot/cold water drains. Hopefully this will be adequate to avoid freeze up's.

[SailorSam20500]

Have you considered the two part spray foams? It is water tight and sticks to what you spray it on. There's a place is Chicago that sells it as a kit with everything you need and I've seen it at Menards.
I remodeled the bathroom in our S&B and also did the rim joists in the basement. Stuff is easy to use and control what gets sprayed. Cover your slide parts and you should be able to put a couple inches of foam on most of the floor. If you do go this route, get a respirator, full face shield with extra googles, and full body tyvec suit.

Alternatively, the underbelly on my trailer ripped off on a drive down to Florida. I'm having it replace under warranty. If you're going to Goshen for the international - I can bring the old stuff down...

[RogerWo]

Originally Posted by SailorSam20500

Have you considered the two part spray foams? It is water tight and sticks to what you spray it on. There's a place is Chicago that sells it as a kit with everything you need and I've seen it at Menards.
I remodeled the bathroom in our S&B and also did the rim joists in the basement. Stuff is easy to use and control what gets sprayed. Cover your slide parts and you should be able to put a couple inches of foam on most of the floor. If you do go this route, get a respirator, full face shield with extra googles, and full body tyvec suit.

Alternatively, the underbelly on my trailer ripped off on a drive down to Florida. I'm having it replace under warranty. If you're going to Goshen for the international - I can bring the old stuff down...

I appreciate your offer, but will not be attending Goshen. I did briefly consider the 2 part spray but decided it would be a real issue if problems developed under the foam after it is applied. If you were wanting to get maximum effect and was not concerned with other possible issues it would be something to consider. After looking into the underbelly at the "rats nest" of wires and piping I would not feel comfortable covering any of it up. The idea of using the spray in some rv applications is interesting.

[tc cruiser]

Originally Posted by RogerWo

2016 Fury toy hauler. Coroplast extends from front of unit to front wall of haul area and from frame to frame. No heat ducts in underbelly. I want to extend the freezing level to at least low to mid 20's for over night stays. Suggestions appreciated. Thanks, Roger

RogerWo
Take a look at Reflectix. Think foil faced bubble wrap. Weight is next to nothing.

https://www.reflectixinc.com/product...ve-insulation/

This is sold at Lowe's and Home Depot.

TC

[Villagerjjm]

Look at Styrofoam insulation panels like the ones made to insulate garage doors. Some are precut for quick nap off to get around things. Perhaps you may want to run some incandescent light bulbs (rough service) which will heat up an enclosed space nicely.

[Xian]

On my Lacrosse 327RES I added a "T" to the heat duct line running to the front bedroom and terminated the new duct line at my fresh water tank. I installed another "T" in the heat duct line running towards the living room in the back of the trailer and sent this towards the water lines that supply and distribute from my water heater which is located in the back of the trailer. Lastly I used foam pipe installation on all water lines that I could access through the panels I cut in the underbelly.

I used the trailer for 2 weeks in early January with temperatures getting down to 20 degrees on a few nights and highs around 30-35 degrees during the day. The water kept flowing but I did go through the propane. Full disclosure....the water lines did freeze on the 3-hour trip to the location, however within a day they were moving water. Having extra cases of bottled water got us through the thaw period.

Good luck.