Insulation and Sound Deadening / by Ray Phung

After all the floor and wall insulation has been added.  

Insulating and sound proofing are an essential aspect of a camper van conversion, and I will talk about both in this article.  Good climbing weather often means cold weather (because cold weather means less sweaty hands, less sweaty hands means more perceived friction!).  Having taken several frigid trips to Bishop, having good insulation for a warm night's sleep is essential. Sound deadening creates a quieter the ride, making 14 hour treks much more tolerable.  It makes sense to talk about both aspects here as they both serve as the base layer of materials that actually touch the van's metal frame.  

After completely emptying the van, we took a trip up to Squamish to climb.  Our major take-away - the empty van is LOUD.  Like extremely loud.  Imagine a large aluminum can on wheels.  Every pothole, bump, or even crack is magnified as the vibrations travels through the sides and roof of the van.  These sounds are startling and make hearing music and Podcasts impossible.

McKinley putting on RattleTrap

Luckily, the automotive sound industry has a number of solutions, including rubber/butyl mats, paints, and foam.  I decided to install RattleTrap XXX by FatMat over the wheel wells. This is a foil back product with 80 mil of thickness. I purchased the 25 sq ft bundle.  This was cut into strips and applied to the wells.  This product was fairly easy to cut and is a peel and stick product.  The remaining squares of RattleTrap were applied to the large blank panels.   

As for insulation, there is so much information on insulation options that it will make your head spin.  I spent days scouring forums and blogs looking for the right insulation among the many options - insulation bats/rolls, rigid foam sheets, reflective bubble wrap, spray foam.  The tricky factor is condensation.  In a camper van, a lot of moisture gets generated from breathing and cooking.  In cold weather, the van sides gets cold and condensation forms from the moist water vapor in the air.  There are two schools of thought from there - either you stop condensation in the first place by creating an air-tight barrier outside of the metal, or you accept that condensation is going to happen and use a material that more easily allows the van to dry out.  

I at first decided to use denim insulation, so i purchased a roll of foil backed insulation for the floor.   This was cut up into strips to lay in between the ribs in the floor.  The denim insulation was very difficult to cut, but we finally got it with scissors.   The strips were taped into place.   I then used the old floor as a template and traced the design on a couple pieces of 3/4" T&G OSB board.  The denim and thicker OSB flooring would provide some additional sound deadening and insulation.  I also used the existing rivet holes to rivet the new flooring into place.  I countersunk the heads so they were flush with the surface.  The rivets held the floor in tight and did not require any additional holes in the floor.  

Strips of foil-backed denim insulation taped between the ribbing of the floor.

McKinley countersinking rivet heads so we can secure the OSB flooring.

For the sides of the van, I began to shift.  Bats of insulation can be stuffed into crevices, but would be difficult to hold up in the large panels (where there is normally windows).  In terms of R-Value, foam generally has more R-Value per inch of insulation.  I considered spray foaming the entire thing, but that's messy, expensive, and runs the risk of deforming the sides of the van.  As a compromise, I decided to use 2" rigid Polyiso foam.  It's super easy to work with (score with a knife, then karate chop to cut).  To secure the foam to the walls, I used 3M 77 glue.  I then used cans of Great Stuff spray insulation to fill around the sides of the panels to further secure them, and to seal off the rest of the van.  

First attempt at spray foam. On the right, I tried to fill a gap much larger than one inch.  Notice how all the foam sank to the bottom of that column to form a crazy blob

Herein lies the headache.  Spray foam was a mess.  I tried to spray in too large of a gap. The warm weather also made the 3M adhesive melt, so the sheets of rigid foam and the spray foam all fell out before it could dry.  And this was all before I wised up and put down a drop cloth, so spray foam got everywhere.  It's a pain to clean up.

So here are my tips:

  1. Use a drop cloth.  And gloves.  And eye protection.  
  2. Don't be over zealous - only use spray foam on gaps smaller than an inch.  I later cut up small pieces of rigid foam to fill up the large gaps, then used spray foam to secure it.  Much cleaner and easier.
  3. Warm the bottles of spray foam up first.  They seem to spread and cure faster
  4. You can cut and trim spray foam easily with a serrated knife.  Be careful not to scratch the paint

A lot of sound and heat also gets transmitted through the ceiling panels.  And we were also worried about condensation on the ceiling (still!)  So on the ceiling, I decided to apply another layer of insulation.  I used Noico Closed-Cell self-adhesive foam. which is supposed to help with both sound and insulation.  We aptly referred to this material as the beer cozy (one night, we conducted an experiment to see if condensation forms on top of a neoprene beer cozy).  We figured that any insulation will help.  

On this side, I wised up and used smaller pieces of foam to fill up the gap and spray foams in between.  Much easier and cleaner.

Beer cozy! And foil tape after a bubble busting session

This foam was easy to cut with scissors; applying it was more challenging.  Once the adhesive touches, it's impossible to get off without ripping the foam.  Also, the foam forms air bubbles if you do not squeegee the air out first.  This was impossible to do on the ceiling, so we ended up applying the foam and popping all the air bubbles with a knife.  We then went back and used foil tape over all the places we popped.  

After the beer cozy, we glued in 1.5" rigid foam and used spray foam in all the cracks to secure it.  The lessons learned above made the ceiling go much more smoothly.  

Before putting any furniture or paneling in, I decided to put in a final layer of Reflectix Bubble Wrap Insulation.  Between the ribs of the van walls and the surface of the rigid insulation, there was a 1/2" to 3/4" space of air.  Reflectix works better when there is a slight air gap.  I figured another layer of insulation wouldn't hurt, as any warmth is welcomed.  And perhaps it would provide an air barrier between the van atmosphere and the metal body if taped in with foil tape.  Electrical wiring was also ran behind this layer, as the final layers of panels and cedar would rest against the Reflectix.

Final layer of Reflectix.  Added it in as i put in furniture and panelling.  The wiring also needed to be installed before this layer went in.  

Once the Reflectix went in, insulation was finally complete.  In all, this took maybe a month to do, and was done along side of rust remediation.  Cutting out individual foam pieces, gluing them into place, spray foaming, adding more deadening, and finally cutting and taping in Reflectix was all tedious tasks and messy work.  But, after a couple cold trips to Leavenworth, the van seemed to be much more warmer when we slept.  Victory!