Insulation installation questions

[David_L6]

My questions are probably pretty basic but I've never done any insulating so I know nothing about it.

I looked at the foam board type insulation at Home Depot. All they had was 1/2". Is that enough? Seems awful thin to me.

Moisture barrier? Is that something separate from the insulation? What is it? What does it look like?

Do I just jam the insulation between the square tubing in the walls then cover back up with the boards that are now on the walls or is the insulation supposed to be fixed in place some way?

Is the insulation supposed to touch the outer skin of the trailer or is there supposed to be a gap between the skin and insulation?

Any pointers would be greatly appreciated.

Here's where I'm at now... Just starting. I do have a portable A/C inside so I can stand to work inside in this Louisiana summer time heat.

[glenpinpat]

I would put the insulation between the crossmembers. I cannot remember what it is called but Home depot has styrofoam insulation that should be the right width. The stuff has a green film on one side. Due to the film you do not need a vapour barrier but you could use insulation tape to tape from the film to the cross members. This insulation is fairly cheap. I have used it in the attic of my store.

[mskobier]

David_L6
I would look at other home center stores or building supply centers for thicker insulation. It looks like you have 1" or maybe thicker square tubing ceiling supports. If all you can get is 1/2" sheets, I would at a minimum double it in the spaces between the supports. I would also get a gallon of the white elastomeric paint designed for RV's and paint the outside roof. You will be amazed at how much difference it will make in the amount of heat that gets radiated from the ceiling.

I used 1" in the walls of my CT and currently have 1" in the ceiling. When I install the ceiling plywood, I will add an additional 1/2" to the existing insualtion. The ceiling is where you gain and loose the most heat.

If you cut the styrofoam insulation about 1/8" longer and wider than the space between the supports, You will be able to press fit the insulation and it should stay in place.

Yes, most of us just cut the insulation to fit between the studs and put the walls back up.

I like the portable air conditioner you have. I have been considering purchasing one for my CT to use until I get a roof top AC.

If you get a chance, check out the pictures in my album.
Keep the pictures coming.

Mitch

[d30gaijin]

Ditto what Mitch said i.e., look at other stores, such as Lowes. That's where I got my 1" thick blue foam insulation material. I cut it to fit between the trailer frames. It appears you need 1" thick insulation too.

I can't help with the vapor barrier as I did not add it. I may suffer for that later... but so it goes.

Don

[OverTheTopCargoTrailer]

Hi David

As a former insulation contractor with 10k houses under my belt & watching everybody else doing a crappie job, I thought I had the correct answer.... BUT I was 1,000% wrong....
I installed insulation, floors, walls & ceilings AND foamed the crap out of all the gaps.

check out my blog and project to see what I did wrong...

http://overthetopcargotrailer.blogspot.com/

Basically what I now know , is that a CT is not like a House. There is a good reason all RV's are built with a wood frame... ANSWER is >>> BECAUSE metal conducts heat like CRAZY... The HEAT or COLD goes through a metal trailer rib, like water flows through a water line. If you want a good insulation job, then you would do what I did AND ALSO, then install a 2nd 1" layer over all the plywood ceiling, walls & floor, so in effect you are building a box inside a box, its that separation between the metal ribs that would allow the insulation to work. ALSO paint your roof white - that works like a charm.

Also I have the same A/C 7,000 LG model, It does not work to my satisfaction, because my trailer is very, very air tight, these units blow lots of hot air to the exterior, WHAT is happening is the A/C is sucking in the hot exterior air. Example i'm just guessing on the CFM, the unit blows 300 CFM to the exterior & sucks in 300 CFM from the exterior, net gain is almost ZERO. The best and cheapest solution is a window unit to the exterior. Next is a roof top A/C unit , and the very best is a mini split A/C unit, if you have an extra $1500...

Let me know how it works out for you ?

Jerry

[David_L6]

Thanks for the tips. I do appreciate them greatly. I'm going to try to touch on all of them....

I'll definitely look for insulation with a film on one side so that it doesn't need a vapor barrier.

I will no doubt have to paint the exterior of the roof with something. It was ~ 102° here yesterday and you could not touch the inside of the roof. Trailer is sitting outside in the sun. I don't have a place to store it inside.

I'll check Lowes next time I have a chance and see what they have. I'll shoot for 1" thick.

OverTheTopCargoTrailer, what you say makes sense (box in a box) but I really can't stand to loose any width. I'll be using this trailer as both a camper and to haul dirt bikes and ATVs to where we will be camping. I have just barely enough room to get an ATV and a dirt bike side by side with plenty of clearance all around. I'll just have to loose some efficiency.

About the A/C.... I chose a portable for several reasons. Stealth (no one can tell it's a camper by the A/C on the roof), ease of installation (two 5" holes in the floor for the intake and exhaust hoses), and portability (I can take it out of the trailer and use it in another trailer or anywhere else I want to use it).

It's a dual hose unit. It doesn't draw air in through the cracks in the trailer like a single hose (exhaust only) unit does. The compressor side is what gets hot and needs the exhaust. This unit also has an intake to bring in cool(er) air from outside to cool the compressor. The evaporator side just re-circulates the air that is in the trailer cooling it down.

I gave the A/C a good test yesterday for about an hour. The trailer was HOT inside as it had been closed up for several days. I turned on the A/C and closed the doors. When I went back and checked the roof was actually cool to the touch where it had been too hot to touch an hour earlier. The temp inside the trailer was bearable, but not all that cool. I think once the trailer is insulated it will get about as cool as you'd want it to inside.

This is the A/C. It also heats. 14,000 BTU cooling, 13,000 BTU heat. http://www.whynter.com/productdetail/ai ... ioners/305






Please keep the tips coming. I'm completely new at this and need all the help I can get.

[OverTheTopCargoTrailer]

Bingo - JACKPOT

That was what I should have gotten, but I did not know about all that suction , so a duel hose would do the trick....
my idea was to use the A/C with the solar panels and 400 amp hour batteries therefore the smaller unit.

Thanks again

Jerry

[jwhite]

I would like to know what the cost was and if it works better than the one I bought.
This one was 350.00 and is a 12000 btu and I thought it would work great but it only works OK.

My trailer has 1inch insulation through out the whole trailer and during the day it's not cool at all,and it takes along time to cool down so you have to run it for some time before it gets cold.
I will say that at night it does work better and will get down to 60 by the morning but by noon it's back up in the 80's,.
I generally sit right in front of the AC so that is how I stay cool during the day.
I will buy a coleman cub for the roof sometime but I am not useing the trailer enough to spend the money on it right now.

[David_L6]

I would like to know what the cost was and if it works better than the one I bought.
This one was 350.00 and is a 12000 btu and I thought it would work great but it only works OK.

My trailer has 1inch insulation through out the whole trailer and during the day it's not cool at all,and it takes along time to cool down so you have to run it for some time before it gets cold.
I will say that at night it does work better and will get down to 60 by the morning but by noon it's back up in the 80's,.
I generally sit right in front of the AC so that is how I stay cool during the day.
I will buy a coleman cub for the roof sometime but I am not useing the trailer enough to spend the money on it right now.

The cost was $496.01 shipped. I don't have a clue if it works better that the one you bought or not. All I can say about it I said in my previous post.

[vtx1029]

I had one of the portable ones too. It was a POS! Didn't cool or heat worth a darn. A $20 ceramic heater put out 50-75% more heat. Cooling was a joke. Hope yours works better then the one I had.

[David_L6]

I had one of the portable ones too. It was a POS! Didn't cool or heat worth a darn. A $20 ceramic heater put out 50-75% more heat. Cooling was a joke. Hope yours works better then the one I had.

Me too, considering I spent almost $500 for the thing!

[OverTheTopCargoTrailer]

David_L6

has the perfect solution....you need duel hoses for the a/c function. A single hose takes 3X as long to cool. Check the underlined graphic below.

Dual hose portable air conditioners function similar to single hose units, but dual hose portable air conditioners have implemented a system to correct some of the inefficiency inherent in a single hose portable air conditioner's design.
A single hose portable air conditioner uses a compressor to power a cooling system to remove heat from the room's air. This heat is then expelled out the exhaust hose. However, the compressor itself creates heat and must be cooled off - and air must be passed over the condenser coil to remove heat from the room. Since a single hose portable air conditioner's only source of air is the room that it is in, air from the room is used to cool off the compressor. This air is then expelled out the exhaust hose.
This system is inefficient for two reasons:
Already-cooled air from the room is being heated up and expelled from the room. This is wasteful, as the portable air conditioner had to expend energy to cool this air.
As air from the room is expelled, other air must take its place in the room. This is what is called "Negative air pressure." Air then seeps in around doorways, and through small cracks and holes in the ceiling, floor, and walls. This air must then be cooled - and it may also bring allergens and impurities with it into the room.
A dual hose portable air conditioner solves this problem by adding an extra hose, which pulls air into the portable air conditioner from the outside to cool off the compressor and condenser coil. The air is then expelled out the exhaust hose.
Operationally, a dual hose portable air conditioner has two main advantages over a single hose unit. A dual hose portable air conditioner will cool a room faster and it will not create a negative air pressure situation in the room. Of course, if you have a dual hose portable air conditioner, you can remove the intake hose and it will function like a single hose unit.
For another explanation of the differences between single and dual hose portable air conditioners, see the graphic below:

http://demandware.edgesuite.net/aabh_pr ... alhose.gif


http://overthetopcargotrailer.blogspot.com/

Thanks again david

[vreihen]

FWIW, the single-hose unit that I have at work for emergencies has a spot molded in the plastic case that looks like it it is where the second hose attaches on the more expensive model. Since you already have the unit, it may be worth investigating whether yours has an obvious location to hook up the second hose and make it a dual-hose unit yourself.....

[OverTheTopCargoTrailer]

Thanks for the idea....

But no such luck...
What I really wanted to install & run off my solar panels was this model:

http://www.acwholesalers.com/Fujitsu_Halcyon_Ductless_Mini_Split_Heat_Pumps_p/94521.htm

But that "supper efficient" ( uses 60% less juice then standard RV unit ) crap only runs on 240 volts , PURE SINE- and that means a whole different inverter or step up transformers, that costs up the wazoo more money. Maybe on my next 8.5 x 20...in a few years I will get lucky ?

http://overthetopcargotrailer.blogspot.com/

Jerry

[8ball_99]

Sorry to say I've never once talked to anyone that was happy with a portable AC. We also 4wheel. We ride SxS so I see quite a few people camping in their cargo trailers.. Most Just have a air mattress and a AC. I've seen quite a few with those roll around ACs, most got them cause they were cheap and easy. They just don't seem to work to well.

As for the insulation. I installed some of that foil bubble wrap reflective insulation in my ceiling and walls then I installed a layer of 3/4 Foam. The reflective stuff ups the R value quite a bit compared to just 1" foam. Price wise wasn't much difference either since 1" was several dollars more then the 3/4. I think it was 11$ vs 16$. Fo the ceiling I also added 1/2 plywood strips and then another layer of blue 1/2 foam. On top of that my ceiling also has a layer of thermo ply between the metal roof and the framing. The Thermo ply is something you have added at the factor, but the other layers aren't hard to do. Best I can tell it works pretty good.. My trailer is 7'wide 6'6"tall and 24' +V long and I can cool it in 95 degree weather with a 9200BTU roof AC.. Thats with it having two roof vents and 3 windows. So I'd say my insulation job is doing the trick.
A layer of insulation on top of the studs is best like mentioned above. I would try to do this on the ceiling if you can. Honestly if your going to finish it out you need some kind of layer between the metal studs and your ceiling paneling anyway. Some 3/4 or 1/2 strips screwed to the studs doesn't take much height away, but should help a lot. I didn't do it on the walls cause I also didn't have the space to loose. One thing I did do on the walls which I'm not sure if it helps at all was tape all the studs with foil tape. It helps hold the foam in but I figured it would also help reflect some of the heat from the studs and make a good air barrier.