Why bother with a bed platform? Because driving a hybrid means you can leave the vehicle in ready mode but the engine only turns on and off as required saving gas and ensuring you're comfortable. You can camp in the car and sleep in a twin size bed with full climate control. It's just too bad the RAV4's backseats don't fold completely flat. It has an annoying incline not only in the folded back seat but also the trunk's load floor itself. It gives the appearance of being flat but really it's at least 6.5" out of level.
This instructable is a simple bed platform for the 2019+ 5th generation Toyota RAV4. This should be compatible between either the gas only or hybrid version as both have the same rear trunk design. Essentially the top edge of the seat back when folded down is still materially higher than the lowest point of the trunk floor near the hatch. To make up this difference I use some 5/8" plywood connected together with 3 piano hinges supported by 2 support beams made up of 1x4. This sits on a 3/4" pine board that has notches cut out to keep the supports vertical and at right angle. The top and bottom of the platform is covered in automotive carpet for a clean look. The total weight is 41.2lbs including the supports. The total cost is about $120 US.
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Step 1: Background
This project, although simple involved a lot of thought and measurements. From how to set it up to how to store it away. When traveling anywhere with this platform, I'm sure there are plenty of things to pack thus keeping it space efficient was key. It went through 2 design iterations. My initial intent was to have this platform sit directly behind the backseat. 2 segments would sit at the same angle as the back seat then another 2 segments would be directly under the tonneau cover. Everything would be attached with 3 piano hinges. This proved to be a tight fit if the rear seats were reclined and I really wanted it sandwiched between the tonneau cover and the rear seats to maximize the height available. Ultimately I just didn't like how to accommodate the angle with it connected all together.
The original 4 segments became 5 once I realized that there was quite a bit of space directly above the spare tire was. The whole platform can fit under there with a bit of redesign. Although it fits, it's not perfect. In retrospect, the carpet and the hinges actually added quite a bit to the thickness thus what was suppose to sit completely under the load floor for it to be flush, now spaces it up by about 0.5". Overall dimensions of the platform is 38" wide by 75" long - 1" narrower than a twin mattress. I plan on getting 3-4" foam mattress topper to put on the platform when I go car camping. When not in use and when in transport the foam will be vacuum packed away.
Step 2: Materials and Tools Needed
- 1 4x8 sheet - 5/8" thick plywood (sanded one or both sides)
- 1 8" x 4' length - 3/4" solid pine board or equivalent (shelving - must be load bearing)
- 1 pc - 1"x4"x8' SPF lumber (any lumber will do as long as it's straight and can bear weight)
- 4 pcs - 36" piano hinges
- greater than 100 pcs - #5 - 5/8" wood screws (or whichever is the correct fit for your piano hinges - count the screws required)
- ~15' automotive carpet
- ~2 cans of spray adhesive like 3M Super 77
- 2 pcs - scrap wood (I used 3/8" plywood cut into 7" x 3" lengths) or metal to align and support from main platform to headboard
- paracord/strapping/carabiners - whichever you see fit to anchor main platform to front seat headrests
- drill / screwdriver (driving that many screws in will be the ultimate strength test for your wrists if you just have a screwdriver)
- table saw
- measuring tape / calipers
- chisel may be required (to cut the notch in the support)
- sandpaper or sander (to finish and smooth out the plywood and/or slightly round off the hard square edges)
- sharp razor blade / scissors (to cut the carpet)
- tin snips (to cut the piano hinge to length for the pine board support)
- router (to round the edges as required)
- contour gauge tool (to transfer the contour of the hatch to the end piece of platform)
- dado blade for your table saw (to cut the notch in the pine board for the support)
- planer (if you want to thin out the pine board by 1/8")
Step 3: Cut the Plywood
For anyone wanting to duplicate and/or improve on this design I've attached my chicken scratch of a blueprint. This is a top view looking down toward the platform. The top of the illustration is the front of the car, and the bottom is the back. The pine board support is illustrated at the bottom in grey. It's attached roughly 4.5" from the back edge of the platform by another piano hinge cut into 3 segments. When folded, the sleeping side of the bed platform is folded in to hopefully keep it clean. Each segment is numbered in red for reference.
The first step is to cut plywood to the 4 main platform segments (#2-5). The are attached by 3 piano hinges. Segment #4 requires a 45 degree chamfer so it can tuck neatly under the load floor. This can be done with a table saw.
Segment #5 is contoured to the rear hatch. I had the hatch closed, propped up this segment 6.5" high and just used a right angle and a pencil to draw a line to match the curve of the trunk. I want to point out that the outside edges of the bottom segment should not be longer than 15.375" as this is the maximum length the load floor will allow if you want to fit it under there. 16.5" center length just provides a bit more length to the bed. I used a jigsaw to cut it out and it was more or less fairly accurate.
Segment #2 requires about 1/2" shaved from the corners. This not only matches the 37" width of segment #1 but also ensures a proper fit under the load floor. It's very tight. Cutting the plywood segments 1/4" shorter per piece wouldn't hurt but I wanted to maximize the length.
Once all the cuts are made, dry fit exactly how the 4 pieces will fit together to understand how the piano hinges are arranged and ensure each pair of segments can be slid in and out together under the load floor. When the hinges are installed, you won't be able to slide each in and out individually so ensure you're comfortable fitting them in as a pair. The trunk itself is made of plastic thus has some give when forced. It's a very tight fit when carpeted with hinges installed.
The platform is 37.75" wide as 38" is the maximum width between the plastic shrouds housing the latches on the backseat. This also happens to be just right to fit under the load floor supports. Segment #1 - the top headboard is trimmed down to 37" to fit directly between the load floor supports.
The headboard is notched so no weight is put onto the armrest when the platform is level. I'm not sure whether this is really required. I just didn't want to leave an indentation in the softex. When the platform is set up, the height difference is negligible.
Step 4: Cut the Supports
I wanted to give segment #2 a bit of support with the 2 support beams. I also wanted to minimize its length and thickness as these were the only 2 pieces of the platform that don't fit under the load floor. 46" long using 1x4" is what I settled on.
The 2 pieces of 46" are cut to match the folded angle of the backseats. It's 2" wide at the tip then 11.5" below that it's at full width of the 1x4 lumber. This is the only aspect that may be different from vehicle to vehicle especially the gas vs hybrid . The hybrid has the traction battery under the rear seats. The cushions therefore aren't as thick compared to the gas only model. The measurements above are for my hybrid model.
To figure this out for your vehicle, you would need the uncut 1x4x8. Have a 6.5" high support in the trunk so that the uncut 1x4x8 can be rested across that and the top edge of the seat folded down. As I have my pine board support 4.5" from the rear edge of the platform, you can start with that and mark off 46" from there. Sit on the top edge of the seat to apply weight on it. This way you can now measure how much of a gap there is between the seat back and the level support beam. This is how thick the tip of the support beam will need to be. I used calipers to measure this. Once you figure that out, you can change your calipers to 3.5" (the max width of the 1x4). Measure back from the 50.5" mark (4.5"+46") to determine how far down the 1x4 to cut. You then have your angle.
Realistically though, the angle will probably change over time based on use. The carpet and padding on the seat back will also allow a bit of room for error. If the angle doesn't match precisely it's not that big of a deal. That simply means the support beam will press down unevenly on the seat back.
To cut, I just drew a line and eyeballed it when using the table saw. This angle actually has a tendency to slide the bed backward thus contouring segment #5 to the rear hatch ensures it stays in place by limiting its movement without damaging the rear hatch.
Segment #6 has two notches cut to match the 1x4 support lumber with a jigsaw. I used a chisel to square the corners. A dado blade on a table saw would work perfectly if available. Just ensure to cut it a bit deeper (about 1/8" to accommodate the piano hinges between segment #4&5) and wider (about 1/16") so the supports can slide in and out without too much difficulty. Don't make it wide enough to give it wiggle room. The tight fit to ensure everything is at right angle. This will keep the pine board and the support beams vertical. The seat back carpet actually has a bit of friction to it so it's unlikely to keel over or shift out of place.
Step 5: Carpet the Platform and Install the Hinges
Carpet the platform
This was my first time carpeting anything like this and it was a learning experience. It was also very tiring. This was done in the kitchen with bulletin board art paper in a roll as a drop cloth. This worked out well. I wouldn't recommend using lightweight plastic sheeting as a drop cloth as any overspray could stick to you with the whole sheet coming up. Instead the stiffness of the paper would crinkle noticeably and I could twist my hand/foot to shake it off. A lot of squatting was involved. My legs were tired. There's plenty of youtube videos out there describing the process so look those up. This spray adhesive will get everywhere so don't wear nice clothes and ensure there's no draft when spraying. It's a very fine mist. You're spraying the adhesive on both the carpet and the plywood, waiting a minute or so until it gets tacky then wrapping it together. No stretching required. You would however, want to ensure to pre-bend the carpet around corners. The carpet didn't overlap anywhere except for some of the edges slightly. I used about a can and a third of spray adhesive and about 14.5' automotive carpet.
I would highly recommend you keep track of the board pieces and orientation to ensure after carpeting you don't lose sight of where and which side to install the hinges. I doubt I could have a nice looking finished edge on the bottom side so opted to just carpet the whole thing - top and bottom even though only the top side is in use. Carpet it in such a way as to keep all the seams on the bottom side of the platform.
Install the hinges
Screw all the hinges in place once centered on each segment. I installed the hinges on top of the carpeted segments. This added to the thickness which I will talk more about later. I could have cut the carpet out from under the hinges and mounted that directly on the plywood or used the table saw to cut a track for the hinges. However I didn't want the carpet to peel away over time.
As segment #6 is attached segment #5 by another piano hinge, you'll have to cut the piano hinge to match the notches on the pine board. I used tin snips to cut the piano hinge to length. Be cognizant of the screw holes available to maximize the number of screws on the outside hinge segments since they are shorter.
Step 6: Finishing
Once complete, you can test fit it in the RAV4. It's a bit awkward to carry around due to the bulk. When the main platform is good to go, you can concentrate on finishing the last step of supporting segment #1.
I had some scrap 3/8" plywood which I used to cut 2 pieces of 7" x 3". This is screwed under segment #2 (ensuring it fits under the load floor). The scrap plywood supports segment #6 and allows it to remain flat with the main platform.
I used two 14" straps with loops on the end for the carabiners to hook onto. A short 4mm paracord is tied to that on one end and with the other - a tent cord tightener. This is finally looped around the larger black carabiner which I use to hook onto the headrest support. The straps, cord, carbiners and cord tighteners were simply supplies sitting around the house. Alternatively some ratcheting straps from Harbor Freight would be fine. It needs to be adjustable as the front seats may not be in the exact same position every time you set up.
Step 7: Final Thoughts and Notes
- The load floor supports may not be very strong. There is a 2.75" gap between the spare tire and the load floor. A piece of wood or rigid foam to span this gap allows the weight of the platform to transfer directly down to the tire rather than relying on the edge supports only.
- Each segment span 20" between the 2 support beams which is a bit wide but hopefully with the piano hinges connecting all the pieces together, the boards will act in unison.
- When stored, the 0.5" gap wasn't there before I applied the carpet and hinges. The bare 5/8" board fit fine with space to spare. However, now that it's carpeted with hinges installed, it creates 3/8-1/2" hump that the load floor sits on top of. It compresses down a bit with weight and overall it's not really much of an issue. 1/2" plywood may fit better with the carpet when stored but when in use, the platform may deflect too much should you sit up and concentrate your weight on one area. Alternatively having 3 supports would also work better. I just opted for 2 supports and 5/8" plywood for a minimalistic approach. The 3/4" pine board support could also be thinner as this is probably what's propping up the load floor the most due to the hinge and carpet under it.
- I seriously considered using steel or aluminum plate and rectangular tube but the costs were prohibitively expensive. Tapping screw holes or welding are two things I have zero experience in. The original intent was to save space when it was initially designed to store behind the rear seats. Now that I figured out how to store it under the load floor it suited my needs just fine. It's still a bit heavy and cumbersome to set up but due to the low frequency of use I think that's a decent trade-off.
- When transporting, the 2 support beams will be tied to the rear headrest to prevent rear occupant decapitation should there be a high speed accident. It fits nicely up there but could also just lay directly on the load floor.
- The full width (37.75") pine board support is meant to give stability so both the front and rear edges provide corner support. I don't want to lean on one side and have the whole thing flip over.
- The back seat when folded down still has some give when pressed. This may show up as a slight slope when it's all set up and done but it should level out once you put some weight on it. This would also mean the headboard (segment #1) would require further adjustment.
Any suggestions and or improvements would greatly be appreciated.