Wall insulation thickness..

[Arne]

My current tear has 1/4" luan inside and out with 3/4" insulation. I'm thinking of going to 1" insulation on the next one. But, that would mean using an odd size wood and rip it all. Unless 5/4 is one inch and cheap enough. I could always do the 3/4" insul thing with some carpet... the wall are just cold to the touch at night.

Anyway, would like to hear what others have done and how they like it..... and do they wish they had gone thicker... I know some don't use any, but where I live and where I camp I want it.

[WarPony]

My walls are a total of 1 1/2" thick with a 3/4" pink insulation core. Soon, I will put some 1/4" thick automotive interior carpeting on the walls, mainly for sound deadening but the heat retention would be an afterthought. I'm a cold sleeper so if I had a 6" wall I'd still probably freeze my nootz off. I will probably build my next one with the same thickness.

[Steve Frederick]

5/4 is 1" thick. It's usually a grade above common pine. Few knots, clearer grain, which wouldn't hurt in the work-ability category!

[gman]

PB, be careful with that lantern in a closed space, no air for the lantern means no air for you, carbon monoxide is heavier than oxygen so when you breath it, it displaces the O2 in your lungs from the bottom up.

[Arne]

I think for now I'm going to toy with 1.5" insulation. That gives a big gain over the 3/4 with no significant weight/width/money penalty.... Thank you all for your input... and oh, it will probably make the walls even more rigid/stronger than they already are.... seems like no reason not to... not sure I can find 1.5 foam insul but can double up 3/4...

[toypusher]

arnereil,

You might want to check into some of the 'foil-bubble-foil' insulations that shoud give you more insulating properties with less thickness!

[Arne]

Kerry, a couple of things... I'm not sure where to get the bubble-foil, and I may need the rigid foam to support the walls, especially the inner wall which will be 1/8 ply... I'm going go be building this to keep the weight down. The first one was fast to get it done without a lot of thought about how much lumber I was throwing at the project. This one will be a slower build with a better and well thought out design... and one thing is the insulation will have to be solid and fill the voids entirely....

[toypusher]

You can get the foil-bubble-foil (fbf) insulation at the box stores these days. Maybe a combination of rigid and fbf would be a consideration to keep the thickness and the weight down. Say 1/2" rigid and 1/4" fbf sandwiched between your inner and outer walls to create a tightly filled void in between the two skins. You would have to check it out for sure, but I seem to remember that the fbf has a 'R' rating of around 19!

[Ira]

The other big advantage of going 1 1/2" is you'll be able to mount your fixtures, switches and outlets totally flush with the wall. I'm having a heck of a time finding boxes to accommodate my 3/4" thickness.

[Steve_Cox]

Hey guys,

You got me researching insulation this morning and I was really suprised how much better the foil/bubble/foil insulates than ridgid foam. The R values of foamboard were between 4 and 8 per inch (depending on brand) versus 14.1 per 3/16" layer of Foil Bubble Foil. The catch in this R business is that more layers of FBF don't increase the R values enough to be important, but more layers of foam board do. Also, R value wise, plywood R values are as follows. Paneling / plywood base, 1/4", 0.31. Plywood, 1/2", 0.63. Looks like a sandwich construction of Foil/Bubble/Foil inside with pink foam on the outside for it's rigid strength qualities might be the ultimate in insulating.... Hope this was of interest..


Steve

[Arne]

The combo idea could work. The 1/4 on the outside would not need as much support as the 1/8 on the inside... so some combination of fbf and rigid, as long as it filled the void, might very well be the best solution. I'll have to see what I can find locally when I get to that point.

[asianflava]

There is a lot of strength in 1.5 insulation.I built a 2'x2'x4' cooler out of 2 inch insulation that lasted throughout 2 summers of camping.I built it using nothing more than rabbit joints and silicon.

You got me thinking Maybe I can build a tougne box using the same construction method. I was concerned about the added weight a tongue box would create but this would be really light weight. I wasn't going to put anything really heavy in the box, just chairs and things that get dirty, dusty, etc.

[jdjernigan]

After reading the above, here is the bubble wrap I found at Lowes...



It's called Reflectrics? R value varies depending on application. In my floor, I used 2 sheets of Dow Styrofoam R-3 3/4"... Thought this would fill a 1.5" inch void....right? Well, it wasn't really not 3/4". I had 5/16" gap left to fill. The reflectrics did the trick.

I will plan to do the same with the walls. Note, I decided not to sandwich it between the panels...left on the interior... to help "reflect" the heat from within in the winter.

Joe

[Grummy]

t... the wall are just cold to the touch at night.

Ok, my first post. I have been drooling over building a tear as well as all those pictures of the ones built by members of this group !

I'm going to build one, and have started drawing. Just not sure when and where I am going to fit it in yet....


Anyhow, Regarding walls "cold to the touch", maybe you could consider just glueing cloth to the walls ? I used to do a lot of Van conversion stuff, and I would routinely line the van with Luan, then glue some 3/8" or 1/2" carpet pad to to the luan, then glue upholstery material to that. It adds a little insulative value, keeps it not cold to the touch and looks great !

If you can do the above, you are adding what you need without reworking the walls.

Grummy

[Arne]

Grummy, I've been thinking about something like that..... it could be as simple as a carpet sample... does not have to be too big... am off for a month's trip in Feb, and will try and figure it out then.... will talk with the sig. other and see what she is agreeable to.... of course, it will have to look good/g/....