How to insulate a Sprinter
We just bought a new Mercedes Sprinter Van (2013, 144" with high roof) and are starting the conversion towards a winterized camper. We live in the Pacific Northwest and love to ski - our goal is to drive the sprinter around ski resorts and camp out in the parking lots, ready for the next powder day! The construction of this van is for us the start of uncountable adventures discovering the area around here. We are outdoors enthusiasts, love to do backpack camping and backcountry skiing, but we also want to have a bit more comfort, specifically in the winter. The first step was, of course, to insulate the walls, the floor and the ceiling of the van to keep the warmth in.
After reading multiple blogs and info sites about Sprinter and van conversions, we decided to use metallic bubble wrap, fiberglass insulation, and a plastic vapor barrier.
In total, it took us about 2 days (6-7 hours a day) with 2 to 4 people working on this to finish the insulation process. It cost us about 300$ for the materials (although we got the fiberglass insulation for free from a friend).
See more How Tos from Audrey here
What you need
Reflectix metallic bubble wrap (we got 150 sq feet and it was just enough for the floor and the walls)
Tuck tape (2 rolls of 66 meters)
Vapor barrier (we got the smallest roll, and it was way too much!)
Spray glue (2 bottles) (we tried Lepage and Nashua. Nashua worked better for us.)
Spray insulation (2 bottles of "GREAT STUFF Big Gap Filler Insulating Foam Sealant" 454 g)
Foam boards (2 sheets of "DUROFOAM DuroFoam EPS Rigid Insulation" 4 x 8, 1 inch thick)
Tools you will need:
Safety first: Goggles, gloves, masks - particularly when working with the fiberglass insulation
Screw driver and allen keys
Step 1: Preparation
The first step to insulate the van is to get it ready to accept the insulation. - Take out everything that is inside the van. - Remove the existing floor with a screw driver or allen key, depending on what attachments you have. The result will be a metallic surface all around in the van. - Close off the driver's cabin with a plastic sheet to prevent having fiberglass all over the seats. Idea : Set up a go pro if you want to do a timelapse video!
Step 2: Start with the floor
We decided to start with the floor since once it is done, you can stand on it and work on the rest of the van. Unroll the reflectix bubble wrap on the floor. Use the exacto or scissors to cut it to the appropriate length. Secure the bubble wrap in place with the red tuct tape. You don't have to glue it all around, just enough to make sure it won't move once the flooring is put back on top. Once you have done the middle piece, work around on the edges by placing the bubble wrap down and cutting it to size. The goal is to cover the whole floor before putting back the top on. Put back the top onto the bubble wrap. Remember the order you took things appart. For us, we had to take out the piece closer to the front benches first and then remove the back one. So when placing them back, we started with the back piece and then the front one. Where there are holes for the inserts to hold down the plywood, use an exacto knife to make a X shape hole. This way you can find the screw hole under and get ready to screw back the insert. Place back the insert piece under the foil and then add the black metal piece. Screw everything back in place!
Step 3: The ceiling
The ceiling of the Sprinter van is separated by about 6 ribs of about 2 inches wide. In between each set of ribs, we placed durofoam foam boards to do the insulation. We decided to use this material for the ceiling since it is easy to place and can hold in place without too much trouble. Measure the distance between the ribs for each casing. Cut with an exacto knife the foam boards to the appropriate size. Place the boards in place (ask a friend to help you!). Use tuck tape to secure the boards to the ribs.
Step 4: The walls: first layer is the bubble wrap
The most time consuming part of the insulation for the van was to work on the walls. We had to use 3 different materials all around, so this means a lot of time. The three layers are bubble wrap, fiberglass insulation and vapor barrier. The first layer, the bubble wrap, is to cut off the cold coming from the outside metal panel. The second layer, the fiberglass insulation, is used to create a larger thickness of air to keep the warmth inside and the cold outside. Finally, the third layer, the vapor barrier, is used to prevent the moisture coming from the inside of the van (think of melting snow from skis, stinky and wet feet, and boiling water and cooking) to go into the fiberglass insulation and create mould. Remember, a van is not like a house, the materials don't breathe as much and moisture can really be a problem inside. (We did not use the vapor barrier on the ceiling or floor since there are almost no risk of having mould on the bubble wrap itself or on the durofoam on the ceiling). Unroll a part of the bubble wrap, measure approximately how much you will need. Cut with scissors to the dimensions. Use spray glue. Read well the instructions on the one you get. With the LePage and Nashua, you need to spray on both surfaces (the bubble wrap and the wall) and let it sit for 2-5 minutes before glueing it together. Place the bubble wrap to the appropriate surface on the walls of the van. Apply pressure everywhere to make sure it is well glued. For the smaller sections (between the ribs), we made sure to cut out little wings to fit on the ribs and behind the ribs when possible. For the even smaller sections (in the ribs), we were sometimes able to add a rectangle of bubble wrap without glueing it in place. The fiber glass insulation will hold it in place.
Step 5: The walls: second layer is the fiberglass insulation
SAFETY NOTE: Use gloves and masks for this part of the work. Fiberglass insulation is not the nicest material to work with, however we got ours for free, so we did not complain. Approximate the size of the pieces you need to cover each piece of bubble wrap. Use scissors to cut to size. In the small sections surrounded by ribs, shove the insulation into place.The ribs should be enough to hold it in place. Don't compact the insulation too much, as it is the little air parts between the fiberglass that creates the insulation. For the larger sections, we used tape to hold the insulation in place. Since we know that there will be the vapor barrier and the final paneling, this is a good enough temporary solution!
Step 6: The walls: foam insulation in the beams
SAFETY NOTE: Use gloves and goggles for this part, as this stuff is really sticky on the fingers and would definitely not be good to have in your eyes. There are still gaps behind some of the beams that are not possible to attain with bubble wrap and fiberglass insulation. For those, we used foam insulation in a spray can. We read only later that you are supposed to fill in only to 50% of the gap with the foam, since it will expand afterwards... So we had to cut out the excess!
Step 7: The walls: third layer is the vapor barrier
The final step is to add the vapor barrier to seal everything. The goal here is to have no air coming from the van to the fiberglass insulation. Start by cutting an approximately good size piece of plastic for each section. For sections, we used the large beams already on the walls to dictate where we were going to separate the sections. For each section, start by using tuck tape on the top part of the piece to secure it in place. Then make sure to cut out space for the wheel for the bottom piece. Make sure the size is ok all around. Then tape down the bottom, and finish with the sides. We had some more delicate cutting outs to do around the ceiling studs, and around the back anchor for the door. With some patience and good scissors, everything can be sealed out properly! YOU ARE NOW DONE! The insulation for the van is complete. If you want a super extra good job, you can also add some insulation in the panels of the doors. We did not get to this part yet. You can also insulate around the wheels, but this has to be done in conjuncture with whatever you want to build around the wheels. Once this is done, the next step will be to cover the insulation with a 'pretty' finish so that it is nice and welcoming to live in the van. Some people use thin plywood, some use plywood covered with fabric or rug. We are thinking of using thin cedar tongue-in-groove slats for a very nice finish. This will come in the next instructables tutorial! As I said in the intro, this is the first van conversion we are working on. We do not claim that this is the best way to insulate the interior of a van, however we believe that we have done a thorough research of online resources and what we present here is a nice summary of the best options we have seen out there, considering our budget, our skills, our schedule, and our future use for the van (winter adventures!). We welcome all comments or questions, since we are curious to see how others have done it