Insulate for maximum space

[Bmotion]

The more I read on insulation and the worry of vapor and rust the more confused I get. I’m now in a mode indecision on what to do. Here are my thoughts. 

Needs

• I want to retain as much height and width as possible.
• Minimum insulation, flooring, walls, ceiling
• Dont plan on super cold conditions often, will try not to be in sub freezing conditions too often but will happen
• Will have heat and plan to install ac eventually
• I want to reduce noise but think the build itself will help this
• Want as easy of install as possible 

My Thoughts

• All the reading has made me fearful of moisture, rust, and mold
• The fear of these things is making me think of using less insulation and finding a method that allows for free air circulation would be best

The decision on insulation is holding me up and want to move to building. Not to mention it seems like the most tedious aspect of the process

Any thoughts or suggestions are greatly appreciated.

 

[Almost There]

See my signature line about worry!

In 40+ years of building interiors in vans I have never yet run across a mold/rust problem caused by insulation or lack thereof. The mold/rust problems were caused by water penetration by holes and or inadequate sealing of windows/vents etc.

The fears of mold and rust are mostly in the minds of those who have yet to live on the road.

We all create moisture every time we breathe, we create more when we cook and use portable propane heaters.

The solution - ventilation. Every time we open the door to go in or out, we ventilate it. Heck 2 doors open - side and back - and we change the air out completely in just a couple of minutes.

I don't turn on the heater without having a window cracked. The higher the heat I put in to the van, the higher the condensation on the windows - why - because the outside air is cold. Are my walls getting wet - nope because the walls aren't as cold as the windows.

Do I open a window or the door if I'm cooking - hell yes! Why - because it gets too darn hot in here if I don't. The few minutes I'm cooking twice a day don't cause any permanent problems because I ventilate. If I'm wanting to cook something for an hour or two like spaghetti sauce, I leave making that dish until I can cook it outside on the Coleman stove rather than on my single burner butane.

I didn't use insulation per se at all in my van because I never intended to stay in cold weather. I 'insulated' against heat infiltration (wrong term and someone will jump all over me for it... ) by using a radiant heat barrier. The only time I've regretted it is this past week when I'm stuck in Canada in November until I can cross the border next week. It's costing me  a bit more a day in propane to keep the van warm because of heat loss that could have been avoided by insulation...oh well! But the little it's costing me this week and next is nothing as compared to the cost I would have been in to to add insulation.

IMO there is little to be gained from insulating the floor, use throw rugs and slippers instead. The walls can be insulated between the ribs so that you don't lose any interior space at all. The ceiling needs insulation because heat rises but again you should be able to get adequate insulation between the ribs.

The easiest way to do it, if you choose to go with insulation, is to use polyiso in 1" thickness. Cut to fit between the ribs, tape it in place with either aluminum tape or that red tape meant for it. Add another layer if you want but don't put the seams in the same place. Done, finished, on with the next job.

Noise is inevitable in a van, get used to it. If it's not road noise, it will be something like your pots and pans jiggling while you drive. I have one cupboard that squeaks  on dirt roads, drives me nuts... I think I forgot to use the glue when I was building it...oops!

 

[Bmotion]

Thanks! Like your no worry perspective and wasn’t really worried until I started reading about it

I like the idea of just doing between the ribs and then using thin cieling material. On the floor too. Then I should be able to just be able stand up fully. 

When you say tape the edges, is that to hold in place instead of gluing? Are you thinking you tape to hold then use the cieling panel to hold in place permently?

 

[lenny flank]

Agree with Almost There.

If you have sufficient ventilation, you won't have any problem with moisture or condensation.

If you are not going to be in an area that is REALLY cold in the winter, you don't need insulation. And I don't have any Reflectix or radiant insulation either. Since I move with the weather and go north in the summer and south in the winter, I never have to face extremes of hot and cold. My sleeping bags do the job just fine.

 

[Almost There]

Thanks! Like your no worry perspective and wasn’t really worried until I started reading about it

I like the idea of just doing between the ribs and then using thin ceiling material. On the floor too. Then I should be able to just be able stand up fully. 

When you say tape the edges, is that to hold in place instead of gluing? Are you thinking you tape to hold then use the ceiling panel to hold in place permanently?

Yes, tape them in place so that they  hold firmly there. Some people glue them to the inside of the metal van wall but then most glues won't take the heat that a van gets exposed to sitting in the sun. Ever put your hand on the outside of a car on a hot day....ouch.

Not only does the tape hold them in place while you get the wall/ceiling panels on, it prevents them from squeaking when the vehicle is in motion.

Some people end up going for months with just the insulation in place while they either save up funds for the next step or do other work and still want/need to use their vehicle.

 

[jonyjoe303]

rtech foam works great on the ceiling its all I use and never had any mold problems and I run a swampcooler every day even in the winter.

For the roof I cut in small sections 1 foot by 1 foot and hotglue the foam. Hotglue drys quickly (less then 5 minutes) and the foam aint coming off unless you pry it loose. 
You can duct tape it to the roof but after a while it will sag and fall off. Hotglue is a more permanent installation, in 5 years never had a foam section come off, heat doesnt affect it. 

You need the foam insulation, it make a big difference in your comfort level, with the foam insulation I can park in the hot sun, close all my windows/doors and spend all day in my van with just the (2 amp) swampcooler running. The more foam the better. rtech foam (find at home depot) is cheap 8 dollars for an 4x8 foot sheet, 2 of them is enough to do your roof and have some leftover.

 

[BinDerSmokDat]

The max R-value will be spray-in insulation.
It also resolves a lot of the condensation worry, because it's bonded directly to the metal skin of the vehicle.

However it can be messy and wasteful, as it can be difficult to apply evenly and you end up shaving a lot off to bring it trim to your wall ribs.

Folks seem to do well with XPS, held in with canned spray foam as adhesive/gap sealer.

Also I do not subscribe to the "noises are inevitable" and "it will never be quiet it's a van/RV/etc." camps.
Having owned and driven a lot of Jeeps/4x4's/bobtails/pick-ups of various makes and vintages from 60's to 00's, with big oversized tires and V8's, I can say that careful planning and soundproofing goes a long way to making for a quiet interior.

Many of the same things you do for good insulation/climate control also help with sound control.
Sealing gaps/holes, adding layers of different density materials, checking that door gaskets seal properly, caulking seams, etc. all keep out unwanted cold/hot as well as sound.

While not very beneficial for insulation, I'm applying Noico self-adhesive, foil faced sound dampening on all walls, ceiling and as much of the interior side of the door skins as I can reach through the access holes as well as interior of the doors.
I have only applied it to a few areas as I mull my noise/insulation options and the difference it makes is noticeable. It takes away the tin can reverberation and lowers the echo-effect in the interior.
I'm mentioning this because it's a step that if you want to include, needs to be done before you insulate.

 

[John61CT]

> max R-value will be spray-in insulation.

Be careful to follow instructions, especially ambient temp limits.

If done improperly bad off-gassing.


> It also resolves a lot of the condensation worry, because it's bonded directly to the metal skin of the vehicle.

Make sure not to leave bare metal unsprayed but sealed off from air circulation, can lead to rusting panels.

 

[travelinjoan]

> max R-value will be spray-in insulation.

Be careful to follow instructions, especially ambient temp limits.

If done improperly bad off-gassing.


> It also resolves a lot of the condensation worry, because it's bonded directly to the metal skin of the vehicle.

Make sure not to leave bare metal unsprayed but sealed off from air circulation, can lead to rusting panels.

Getting ready to get my van and the first thing on my list is insulation.

What do you think of thinsolate (Not sure of the correct spelling).  Also  If you use polyiso foam boards, do you need reflectex too.  Would the reflectex  go on under the foam or over the foam.   Any infor is greaty appreciated.

 

[John61CT]

Thinsulate is great but very pricey, IMO only worth it for those known to be hyper-sensitive to chemical exposure.

 

[John61CT]

Reflectix is only useful on the cool side of an air gap or maybe against glass keeping radiant heat out. As a big awning casting shade from overhead would be ideal.

Air gaps take up space, better filled in a van with IMO foam.

It does nothing against conduction.

As a vapor barrier pushed against real insulation (reducing convection) might as well just use a strong plastic.

 

[RVTravel]

The ole yahoo group "expert" used to recommend sandwiching polyiso with reflectix on both sides. I'd imagine most don't do that though.

 

[John61CT]

Well the side facing out to the sheet metal is doing something in summer, to the extent it's a dead air gap in between.

But reflecting low grade heat back into the living space, not effective.

And for the former scenario I'd prefer spray foam sealing up all the metal and spaces between and around the rigid panels so no air movement in any direction

Getting that whole envelope sealed up is very important, more so than going thick R-value but letting convection and conduction transfer energy around the panels.

Air gap + Reflectix is just not as effective a use of the precious interior space loss.

A tight vapour barrier is great, but no shiny needed for that.