How to Insulate Skoolie Walls

Replacing the insulation in your skoolie walls is an important step.  For a few reasons:

• The old insulation in there is nasty, old, and not really doing much anyway.
• You want to inspect and make sure there are no leaks in the lower walls.
• Re-insulating with a higher R-value material will help A LOT with heating and cooling your skoolie.

What type of insulation should I use?

That really comes down to preference!  We chose Rockwool Mineral Wool Comfort Batt (you can get it at Lowe’s) primarily because of its high R-value and moisture resistance.  It also has the added benefit of being a great sound absorber, which helped greatly in soundproofing the recording studio.  Many choose spray foam for their skoolie walls and ceiling; that application didn’t work for us because of cost and also because spray foam is not great for sound absorption.

Note: This guide is only applicable if you’re choosing to insulate with batting material.

Let’s dive in!

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Tools & Materials You’ll Need:

• Rockwool Comfort Batt
• A stone wool knife
• Sharpie marker
• Gloves and safety glasses
• Respirator masks (get a pack of 20 and save money in the long run)
• Impact driver (we got this drill/impact driver combo kit and it served us well through the whole conversion!)

Step 1 – Construct a cutting box

1. The insulation we bought came 3.5 inches thick.  The lower part of the walls in 2 inches thick.  We could have compacted it to fit, but this will result in lost R-value. So we decided to reduce the thickness of each piece of insulation for the lower walls. To do this:
2. Build a three-sided frame that matches the width and length of the batting.  Construct it with wood cut at 2″ width.  It will look like this:

Step 2 – Cut the pieces of insulation for the lower walls

1. Go section by section.
2. Measure the width and length of the section, then cut the insulation with the stone wool knife to create your panel.
   • Cut in short motions back and forth (not long, sweeping cuts).  Cutting in a short back-forth motion will make a clean cut with very little pulling of the material.
3. Now you need to make the panel 2″ thick.  Place the panel inside the frame and cut along the top of the frame, resting the saw along the frame as you cut.  Like this:

Step 3 – Insert the insulation into the lower wall sections

Okay, here’s the deal.  In the above video, you see me using a piece of wood to squeeze insulation into the lower part of the walls.  That was dumb.  I thought it was necessary because of screw ends sticking into the lower skoolie walls from exterior rivets.  Again, dumb.  It turns out that those screw ends were from…well, screws.

SO.  We ended up removing the insulation Norlan and I put in the lower walls (it was all squished and messed up from my wood ploy).  Then we did this simple installation method:

1. Go outside.  With the impact driver, remove each screw.  Keep them together in a bucket or bag.
2. Insert the panel you cut to match the section of lower wall (it will slide right down).
3. Repeat for all sections of lower wall.
4. Replace the screws.

Step 4 – Cut and install insulation for rest of wall space

1. As you see in the video, we kept the original 3.5in thickness of the insulation for the main part of the walls.  So there’s no need to use the frame for this step.
2. Just measure the section of wall, cut the insulation to match (adding .25 inch on each side), and plop it right in.  If you’ve done your measurements correctly and added that extra .25 inches on each side, it should fit snug enough to hold itself up.
   • Insulation isn’t cheap, so it’s worth the extra brainpower to play tetris when cutting your different sections of insulation.  Try to use up the whole panel, rather than having lots of extra pieces!

Step 5 – Use leftover pieces to fill upper walls

Use all the extra pieces to fill in the cavities in the wall space above the windows.  Have fun with it!  Treat it like 3D tetris!

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Congrats!  Your skoolie walls are done!  Now go take a shower, ’cause chances are you are super itchy from that stuff!  Next up, framing and planning the electrical for your walls!