3M™ Thinsulate™ SM600L is one of the most popular insulation choices for Mercedes-Benz Sprinter conversions. It's lightweight, it absorbs road noise, it doesn't absorb water, and it's easy to cut and fit around the ribs and curves of a van shell. This guide covers how much you need for your Sprinter, what tools to have on hand, and how to install it step by step.
Written by Kei Project, a 3M Preferred Converter for 3M™ Thinsulate™ Acoustic Insulation.
Why Thinsulate SM600L for a Sprinter?
- Absorbs road noise: fine polypropylene fibers absorb airborne sound, especially in the mid to high frequencies you hear on the highway.
- Moisture resistant: the fibers are hydrophobic, and 3M states there's no need to install an additional waterproof layer. It also resists mold and mildew.
- Lightweight: about 0.95 lb per cubic foot, so it adds very little weight to your build.
- Odorless and fire-rated: 3M lists SM600L as odorless, and it meets FMVSS 302 for flammability in automotive interiors.
- Easy to work with: cuts with scissors or a utility knife and conforms to irregular cavities.
Full specs, including composition, weight, thickness and sound absorption, are on our SM600L specs page.
How Much Thinsulate Do I Need for a Sprinter?
SM600L comes 5 ft (60 in) wide and is sold by the linear foot, so every linear foot covers 5 square feet. These are the amounts we recommend for the walls and ceiling:
| Sprinter | Thinsulate | 3M 90 adhesive |
|---|---|---|
| Sprinter 144" wheelbase, high roof | 50 linear feet | About 3 large cans |
| Sprinter 170" wheelbase | 60 linear feet | About 3 large cans |
| Sprinter 170" extended | 70 linear feet | About 4 large cans |
Our rule of thumb is one large can of 3M™ 90 spray adhesive for every 20 linear feet of insulation. Each Sprinter kit above is sold as ready-to-handle 10-foot sections, and the Sprinter 144 is also available as a pre-cut kit for the 2007-and-newer high roof. Building a Transit or ProMaster instead? See the full sizing chart or try our Thinsulate calculator.
Tools and Supplies
- 3M™ Thinsulate™ SM600L, sized for your van
- 3M™ 90 spray adhesive
- Sharp scissors or a utility knife, plus a straightedge
- Tape measure and a marker
- Cardboard or kraft paper for making templates
- Degreaser or isopropyl alcohol and clean rags
- Gloves, eye protection, and a respirator rated for spray adhesive
- A trim panel removal tool
How to Install Thinsulate in a Sprinter, Step by Step
1. Strip and clean the van
Remove the factory panels and anything mounted to the walls and ceiling. Vacuum out debris, then wipe the metal with a degreaser or isopropyl alcohol so the adhesive bonds to a clean, dry surface.
2. Run your wiring first
Plan and run wiring for lights, fans and outlets before you insulate, so you're not cutting into finished insulation later. Keep factory drain holes clear.
3. Plan and template your panels
Break the van into sections: upper and lower walls, ceiling bays, rear doors, slider door and pillars. For the large flat areas, trace a cardboard template first, then use it to cut the insulation. For tight cavities, cut strips you can tuck in by hand.
4. Cut while it's compressed
SM600L ships compressed, typically around 1/2" to 3/4" thick straight off the roll. It's easiest to cut and install in that state. It will expand toward its full loft of about 1.65" (42 mm) over the following weeks.
5. Get the orientation right
Place the white fiber side against the van's metal and the black scrim facing the interior. The scrim protects the fibers and gives you a clean surface behind your wall panels.
6. Spray adhesive and press in place
Spray 3M™ 90 adhesive on the metal, following the directions on the can, and press the insulation into place without stretching it. Work one section at a time, and spray with the doors open and good ventilation.
7. Fill the cavities, but don't pack them
Tuck insulation into the ribs, pillars and door cavities so there are no large gaps. Avoid packing it tightly, because the material performs best when it has room to loft.
8. Close up the walls
Once everything is covered, install your wall panels, ceiling and trim. The insulation will keep recovering its loft behind the panels.
Common Questions
Do I need a vapor barrier with Thinsulate?
3M states that Thinsulate's moisture resistance means there's no need to install an additional waterproof layer, and its hydrophobic fibers don't absorb water.
What is the R-value of Thinsulate SM600L?
3M doesn't publish an R-value for SM600L. It's rated as acoustic insulation, though many builders use it for both sound and temperature comfort. See our SM600L FAQ for more.
Can I insulate a Sprinter myself?
Yes. SM600L is one of the friendlier insulation materials to install: it's light, easy to cut, and conforms to the van's shape. The main time is spent removing panels and templating.
Get Thinsulate for Your Sprinter
Kei Project is a 3M Preferred Converter for 3M™ Thinsulate™ Acoustic Insulation, supplying genuine SM600L with lot traceability. Shop the Sprinter 144, Sprinter 170 and Sprinter 170 Extended kits, or buy SM600L by the linear foot.