In our van builds we add an extension behind the front cab area that serves three main purposes:

• Adds storage in an easily accessible area of the van. You can use it for anything that you want access to regularly such as shoes or pet supplies.
• Covers the transition from the cargo floor to the cab area, which is an unsightly part of the van and awkward to work around.
• Gives our dog a place to sit or lay down while we are driving. The area between the seats without this cab extension was not long enough for him, resulting in his butt falling into the cargo area.

Overview

Time required: 4-6 hours (2-3 days with paint due to drying times)
Difficulty: Moderate

The cab extension/storage area is built using 3/4″ birch plywood, piano hinges, and cabinet bumpers. It is assembled with pocket screws, wood screws, and wood glue. It is then secured into the van with pocket screws and two M8 machine screws that are screwed into rivnuts installed in the cab area.

I would rate the difficulty of this project as moderate. The only part that I think can be tricky is the piece that butts up against the cab floor and we can provide you with templates for that part. Keep reading for details.

Materials

Materials required for the construction of the cab extension/storage area are shown in the table below. You will not need nearly an entire 4′ x 8′ piece of plywood to complete this project, so the total cost goes down considerably if you are able to use it for other projects as well. This is also true for the screws and glue.

I generally don’t include tools in a material list, but rivet nut installers are not exactly common tools that everyone owns. if you are building out a van, there’s a good chance you have one. I would also say that the step involving the rivnuts is probably not required, but it made me feel better about the sturdiness of the whole thing. Paint is not included in the material list; make sure to use something durable such as semi-gloss or gloss since this will be in a high use area of the van.

Line	Product		Ordered	Price	Total
1		3/4 in. x 4 ft. x 8 ft. PureBond Birch Plywood	1	$55.98 each	$55.98
2		1-1/2 in. x 48 in. Oil-Rubbed Bronze Continuous Hinge	1	$10.78 each	$10.78
3		1/2 in. Clear Adhesive Bumper Pads (16-Pack)	1	$3.45 pack	$3.45
4		#8 1-1/4 in. Square Maxi-Loc Head Coarse Zinc-Plated Steel Pocket-Hole Screw (100-Pack)	1	$4.77 pack	$4.77
5		#8 x 1-1/4 in. T-Star Drive Flat Head Partial Thread Yellow Zinc Multi-Material Screw (240 per Box)	1	$9.50 pack	$9.50
6		Titebond III 16 oz. Ultimate Wood Glue	1	$7.98 each	$7.98
7		M8-1.25 x 25 mm Phillips Pan Head Stainless Steel Machine Screw	2	$1.34 each	$2.68
8		30pcs M8 Rivet Nuts Stainless Steel Threaded Rivet Insert Nuts Rivnuts Nutsert M8-1.25mm	1	$8.99 pack	$8.99
9		Astro Pneumatic Tool 1442 13″ Hand Rivet Nut Setter Kit – Metric & SAE W/ 60pc Rivnuts	1	$71.63 each	$71.63

Cut List

Below is the list of cuts that we made for this project. These should work for a Ram ProMaster with 136” wheelbase, but you should double-check all measurements against the actual van measurements. If you are adapting this to a different van make and model, these measurements will not be valid.

Part #	Part Description	Quantity	Length	Width
1	Cab floor extension *	1	35 1/8″	3 1/4″
2	Left and center side walls	2	6 1/2″	4 1/8″ **
3	Right side wall	1	2″	4 1/8″ **
4	Passenger side cover *	1	11″	7 7/16″
5	Front wall	1	46″	4 1/8″ **
6	Left lid	1	21 5/8″	6″
7	Right lid	1	13″	6″

Note that the 4 1/8″ dimension for the walls depends on the thickness of the floor in your van. Our van’s floor is composed of 3/4″ thick furring strips, 3/4″ thick OSB, 1/16″ underlayment, and 9/16″ bamboo hardwood flooring. This gives a total floor thickness of 2 1/8″. You may either adjust the dimension based on the thickness of your floor or measure the distance after creating the cab floor extension piece (Part #1 below).

The parts are shown in the image below numbered according to the cut list.

Instructions

Important: Please read all steps before starting so that you are familiar with the process. In addition, since there are so many van layouts, you may have to make modifications to dimensions to make this work in your van.

Painting tips: If you are planning to paint or apply a protective coating (polyurethane or polycrylic), there are two common ways to do this: (method 1) paint all pieces prior to assembly or (method 2) paint all pieces after assembly. We like to paint prior to assembly (method 1) because it allows us to use a paint roller over every surface, which results in a much smoother painted surface. However, you must use painters tape to mask over all adjoining surfaces. This is so that wood glue can be used during assembly. Wood glue will not bond painted surfaces together. If you forget to mask a particular surface before painting it’s not a big deal. Just take some gritty sandpaper and remove the paint. If you are using method 2 I recommend painting the entire piece before installing in the van to avoid getting paint on the van. The instructions below assume method 1.

1. Create templates for parts 1 and 2 using your preferred template material and method. I like to use foam board and scribe with a compass. For some tips and tricks on how to scribe with a compass, check out this article.
   Want to skip this step? These are the only difficult cuts required in this project; if you want to skip this step, you can order templates from us and we will deliver 1/4″ MDF templates that can be traced onto your plywood and cut with a jig saw or router flush-trim bit. Templates are $20 plus shipping. If you are interested, please contact us and mention this template!

2. Trace templates onto plywood as shown in the photo below for parts #1 and #2.

3. Cut along traced line from step 2 using a jig saw with a fine finish blade. After cutting, check the fit in the van as shown in the photo below.

4. There are two round holes in the body of the van underneath the cab extension piece and between the two front seats. Locate these and install two M8 rivnuts using the rivnut installer tool.
5. Mark the location of these M8 holes on the cab extension piece (part #1). They should be 3/4″ from the back edge of the piece. See the photo below for locations.
6. Drill clearance holes using a 3/8″ diameter drill bit. Countersink the screw heads using an 18 mm forstner bit.

7. Cut the rest of the plywood pieces according to the cut list above, making sure to adjust the height of the wall pieces (#2, #3, and #5) based on the thickness of your floor.
8. Cut the piano hinge to the lengths of the left and right lids (parts #6 and #7). The piano hinge can be cut with a hack saw or a table saw. Make sure that you are wearing safety glasses while cutting. If you are concerned about rust along the cut edge, there are stainless steel piano hinges available, I think at Lowe’s. Or, you can do what we did which was to apply metal paint along the cut edge. Use either a paper towel or a cue tip to apply the paint.
9. With all the pieces cut, test fit in the van to make sure there will be no issues with assembly, as shown in the photo below. You may have to remove the plastic panel piece at the bottom of the passenger side support column. This piece will be reinstalled at the end, but will require cutting.

10. With the pieces still test-assembled, mark with a pencil the boundary between the top edge of the wall pieces (#2, #3, and #5) and parts #1 and #4. These marks will be used to remove 1/8″ from the top edge of the wall pieces (#2, #3, and #5) so that the cabinet bumper pads (line #3 of the materials list) can be installed and the lids will lie flush when closed. The 1/8″ of material removed is the thickness of the cabinet bumper pads. The images below show how this looks when completed.

11. I recommend using a table saw to remove 1/8″ of material up until the boundary line drawn with the pencil in step 7. Then use a jig saw to remove the remaining material. Steps 7 and 8 can be skipped if you do not wish to use the bumper pads.
12. Drill pocket holes using a pocket hole jig between parts #2 and #5 and between parts #3 and #5. Also drill pocket holes that will attach the wall pieces to the floor of the van. See the photo below for example placement. Make sure that pocket holes are placed on the inside of pieces so that they will not be visible when the lids are closed.

13. For those of you who prefer method 1 for painting, now is the time to paint all pieces. Remember to mask areas of adjoining surfaces so that wood glue can be used in the assembly. If you prefer method 2 for painting, you do not need to paint yet.
14. Assemble the wall pieces (parts #2, #3, and #5) with glue and screws, as shown below left. Clamp pieces together to avoid movement while tightening pocket screws. Use a square to check parts for squareness before tightening. The center-to-center distance between the left and center walls is 21 1/2″ as shown below right.
    Tip: I like to tighten pocket screws without wood glue initially. The reason I do it this way, even though it adds a step, is because the wood glue makes the pieces slippery, and they tend to slide around as you are clamping them together. So my recommended process is as follows:
    1. Clamp parts together (no wood glue).
    2. Tighten screws.
    3. Unscrew screws and remove clamps.
    4. Apply wood glue to adjoining surfaces.
    5. Tighten screws to permanently affix pieces.
    6. Wipe off any excess glue. The wood glue requires time to dry that varies depending on brand, but if the pieces are screwed together as well as glued, you can continue building without waiting for it to dry. If you are gluing without using wood screws, you must wait for parts to dry before handling.

15. Drill a pilot hole between parts #4 and #1, as shown below. Glue and screw using a #8 wood screw. The two pieces should lie flat and flush.
    Alternatively, you could make parts #1 and #4 from a single piece of plywood by combining the two templates. This makes assembly simpler, but the single large piece is harder to cut as you cannot do the straight edges entirely with a table saw.

16. Drill two pilot holes (using a countersink bit) between parts #1 (cab floor extension) and #2 (left and center walls). These should be 21 1/2″ inches apart. Affix parts using #8 wood screws (we will glue later). See photos below. The larger holes are for the M8 bolts do not need to be screwed in place yet.

17. Drill two pilot holes (using a countersink bit) between parts #4 and #5 and a third pilot hole between parts #4 and #3, as shown below. Affix all parts using #8 wood screws (no wood glue yet).

18. Attach the lids (see photo below):
    1. Attach the piano hinges to the lids. Clamp the piano hinges to the lids and drill pilot holes using a 1/16″ drill bit. The piano hinges should be flush to the lid piece on the left and right side and the bottom.
    2. Attach the piano hinges to the cab extension piece (part #1). Include a 1/8″ gap from the left edge in order to prevent interference with existing cabinetry (The requirement for this gap depends on the layout of your van; you should adjust any dimensions that will help this piece fit better in your setup). There is a 3/16″ gap between the left and right lid and between the right lid and the passenger side cover (part #4).

19. For those of you who prefer method 2 for painting, now is the time to paint.
20. Move the cab extension into place in the van, as shown in the photo below.

20. Attach cab extension piece to cab floor using M8 bolts. Do not go very tight for this step. See photo below.

21. Open the lids and screw pocket screws into the holes that attach the wall pieces (parts #2, #3, and #5) to the floor. You probably have some pocket screws under the passenger side cover (Part #4) that are not accessible. That will be handled in the next two steps, just get the pocket screws that are accessible tightened down to the floor.
22. Now that the wall pieces are attached to the floor, remove all screws holding parts #1 and #4 in place, including the M8 bolts.
23. With these two parts removed, tighten the remaining pocket screws into the floor that were previously inaccessible.
24. Glue and screw parts #1 and #4 back into place, including the M8 bolts. The M8 bolts do not need to be tightened too much, otherwise you could deform or crack the plywood.
25. Reinstall the plastic panel that covers the bottom of the passenger side support column. You will need to trim the bottom of this piece off. Clamp it to a board and use the jig saw with a fine finish blade to trim the plastic. It should cut easily and leave a smooth finish if the right blade is used.

That completes the installation of the cab extension/storage piece. Enjoy this additional storage, and, if you are a dog person, hopefully your furry friend will enjoy the additional leg room. An easy solution for a dog bed in this area is to cut a piece of foam to fit between the seats and cover it with a king size pillow cover. It is approximately the same size.