Isulating the Walls

[gav.uk]

Hi all,
Has been a while since i started & havent progressed much. Both profiles cut, floor constructed & bits & bobs bought.
i have a question, has anyone insulated the walls of thier trailer.
As the ¾" ply is was given for my side walls is used for concrete casting it has a black covering on it whis is most likely sprayed on so cant be taken off, along with the ply i was given a roll of frost insulation to. As the inner walls will be black i was thinking of adding a ¼" ply to the inside & insulating inbetween. Just wondering if anyone else has done this as i was thinking there may be an issue with condensation.
Cheers, Gav.

[Wobbly Wheels]

Spaces with still air and a temperature differential are what give you condensation. If you can either eliminate the air spaces or prevent the moisture laden vapor getting into them (vapor barrier), you can avoid it.

I'll leave it to others to comment on the wisdom of making such a small space airtight (there's a thread about it in here somewhere), but many of the build journals I've read have insulated walls.

I can tell you from my own experience that rigid foam is better than fiberglass batts and some builders here have built their trailer's structure out of foam.

I would question the 3/4" ply for two reasons.

First, is the weight issue - overkill isn't bad in itself (especially if it's free!) but I wonder if it's a false economy because the frame and suspension will need to be beefier, fuel consumption will be higher, and a bigger tow vehicle will be needed. Presumably you've already got the rig to pull it so I assume that one's a wash. If you're using the frame in your album, I could see that thing getting to its gross weight pretty quickly with heavy ply.

Second, there are a few products that can be sprayed on form ply so it breaks loose. I would be concerned about the smell and the fumes. Remember you'll be sleeping in this box for hours at a time in (hopefully) warm weather.

Then again, I'm just some guy on the internet throwing in his .02 so I could be full of it

[dh]

I'd do more research on the "black coating" (probably a water rsistant coating to keep the wood from sucking the water out of the concrete). You may have a hard time getting anything to stick to it, it may be toxic... I used 3/4" ply and cut out my frame from that. A litle less economic, but a huge time saver. I drew out how I would have framed it, then just cut it out. I put 3/4" foam in the holes" left and glued 1/8" Baltic Birch to both sides of the frame/foam. Beware, a small space like that painted black on the inside will feal about half the size it really is.

[gav.uk]

Hi guys,

Thanks for your input. I can understand the issue with weight & as suggested am going to cut out a lot of the side walls & used the 3/4" ply as a frame with 1/8" ply on the inside & ally on the outside, but as i have a company car the fuel isnt realy an issue (but dont tell my Boss )
The chassis is aluminium & has overrun breaks fitted & came from a caravan so is ready made & just needed the back trimming down to the length i wanted. I will be bracing it across the width with some angle just to give myself piece of mind but it would be rigid enough without it as that is how it was originaly constructed, but ive been told im over engineering it, but id rather have it too strong than it fall apart on the motorway
The black covering is to stop the ply absortbing water so i will probably sand it off just to make sure the glue has a good surface to adhire to.
Thanks again for your input, im hoping for good weather this weekend so i can crack on with it, but if the weathers too good i'll have a dilema, Teardrop build or go Paragliding?

[gav.uk]

On the subject of heat ive aquired an Eberspacher cab heater & am looking at heating a tent/awning with it also, hopefully giving me planty of scope to go camping for most of the year, but as you say it wont take much to get it up to temperature