Toasty Toes: Installing 2-Inch Extruded Polystyrene Foam Floor Insulation in Your Skoolie

Converting a school bus into a comfortable and efficient home on wheels (AKA a skoolie), is an exciting endeavor. Ensuring your skoolie is well-insulated is essential for maintaining a comfortable interior temperature in all seasons. One crucial aspect of insulation is the floor, as it can help regulate the temperature, reduce noise, and provide a solid foundation for your interior build. Here's why we chose extruded polystyrene. In this post, we'll guide you through the process of installing 2-inch extruded polystyrene foam floor insulation in your skoolie to make your adventures more comfortable and to help keep your toes and everything else as warm as possible.

Why Extruded Polystyrene Foam?

Extruded polystyrene foam (XPS) is a popular choice for skoolie floor insulation for several reasons:

1. High R-Value: XPS has an impressive R-value, making it an excellent thermal insulator. It helps keep the interior temperature stable, whether you're dealing with a hot summer day or a cold winter night.

2. Moisture Resistance: XPS is highly resistant to moisture, which is a crucial factor when dealing with potential condensation issues in a skoolie.

3. Durability: XPS is a robust and long-lasting material that can withstand the rigors of the road.

4. Easy to Work With: It's easy to cut and shape, making it a practical choice for DIY skoolie builders.

Materials You'll Need

Before you start the installation, gather the necessary materials and tools:

• 2-inch extruded polystyrene foam sheets (We used 8 sheets)

• Measuring tape

• Circular saw

• Polyurethane construction adhesive (You need more than you think, think 3 per XPS sheet, maybe 4)

• Caulk gun

• Safety glasses

Trent Measuring Foam

Cutting XPS

Dryfitting

All the Glue

Weighing things down.

Done!

Step-by-Step Installation Guide

1. Measure and Prepare: Start by measuring the dimensions of your skoolie's floor to determine how much XPS insulation you'll need. Make sure the insulation sheets fit your space correctly, allowing for a snug fit without gaps. Be sure to cut the foam a bit shorter than the width of your bus so you have enough room to clear the chair rail. For us it was about 1/2 inch.

2. Cut the XPS Sheets: Use a circular saw to cut the XPS sheets according to your measurements. Be sure to wear safety goggles (maybe even a respirator) during this step to protect yourself from any loose foam particles,

3. Clean the Floor: Ensure that the floor of your skoolie is clean and free of any debris or dust. This will help the adhesive bond more effectively.

4. Apply Adhesive: Load the caulk gun with the polyurethane construction adhesive. Apply a generous, continuous bead of adhesive to the floor. You can also apply adhesive to the XPS sheet itself for better adhesion.

5. Place the XPS Sheets: Carefully place the XPS sheets onto the adhesive-covered floor. Make sure the sheets fit tightly and securely without any gaps or overlaps.

6. Weigh Down the Sheets: Use heavy items to weigh down the foam panels as they dry. No need to purchase something specific here, we used some cinder blocks from a previous project. You could use jugs of water, scrap boards, those weights sitting in your basement that you'll probably have to sell before you start bus-life, it just has to be something heavy that you can distribute evenly across the floor.

7. Wait for Adhesive to Dry: Allow the adhesive to dry according to the manufacturer's instructions, typically for 24 hours. We didn't have enough weight to do multiple panels at a time so we did 3 panels at a time, waited for them to dry at least half the time and then started on the next sheets.

8. Flooring Installation: Once the XPS insulation is securely in place, you can proceed with your chosen flooring material installation. This style of floor insulation does not require any framing also called a "floating floor" because we wanted to avoid thermal bridging. There are many flooring options including laminate or hardwood -- We chose 1x12 pine boards for our flooring.

Installing extruded polystyrene foam floor insulation in your skoolie is a worthwhile investment in creating a comfortable, energy-efficient, and cozy living space on wheels. With the right materials and a bit of DIY spirit, you can ensure that your skoolie is well-prepared for all seasons...or at least most of them, we'll see how we fare in Alaska. Safe travels and happy adventures in your well-insulated skoolie!

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