Troopy Bed Setup: How to Build a Sleeping Platform
Why a Dedicated Bed Platform Changes Everything
The 78 Series Troopy is one of the most capable touring platforms on the planet, but its cargo area arrives from the factory as a blank canvas. Tossing a swag in the back works for the first trip; after that, most owners quickly realise that a properly engineered sleeping platform transforms the vehicle. You gain a flat, elevated, lockable sleeping surface with organised storage underneath -- no more digging through gear at midnight, no sleeping at an angle on uneven cargo.
A well-built platform also improves load distribution. Gear stored beneath the platform sits lower in the vehicle, lowering the centre of gravity compared to stacking it above seat height. Done correctly, a troopy bed setup is one of the smartest investments per dollar you'll make in the build.
This guide walks through every stage of the build: planning, materials, dimensions, frame construction, wheel arch management, securing, and finishing. Whether you're going timber or steel, fixed or removable, the principles are the same.
Understanding Troopy Interior Dimensions
Before you draw a single line on your design, you need accurate measurements. The following figures are representative of the 78 Series cargo area, but individual vehicles vary slightly depending on build date and factory fit-out. Always verify against your own vehicle before cutting materials.
| Measurement Point | Approximate Dimension | Notes |
|---|---|---|
| Cargo bay length (floor) | 2,350 -- 2,420mm | Rear door seal to back of seat box |
| Cargo bay width (at widest) | 1,820 -- 1,860mm | Measured at door opening |
| Width between wheel arches | 1,580 -- 1,650mm | Narrowest usable sleeping width |
| Wheel arch height from floor | 420 -- 480mm | Determines max platform height at rear |
| Interior ceiling height | 1,150 -- 1,250mm | Standard roof; hi-roof adds ~300mm |
| Wheel arch intrusion depth | 80 -- 110mm each side | Horizontal protrusion into cargo space |
With a standard roof troopy, a platform at 400mm height leaves approximately 750mm of headroom above the sleeping surface before the mattress is added. Factor in a 100mm mattress and you're sitting up with roughly 650mm of clearance -- tight but manageable for most adults. A hi-roof conversion changes the equation significantly, allowing a much more comfortable sleeping height.
Fixed vs Removable: Choosing Your Design
The first design decision splits every troopy bed build into two camps. Fixed platforms are welded or permanently bolted to the cargo floor. They're more rigid, require fewer fasteners, and feel structurally planted. The trade-off is inflexibility -- once it's in, the vehicle is committed to that configuration.
Removable platforms use quick-release anchor points, typically pin-and-clip systems or heavy-duty latches, allowing the entire platform to be lifted out when the vehicle needs to work as a tradie ute, carry livestock, or haul oversized cargo. Most touring-focused owners choose removable, accepting the minor engineering complexity in exchange for long-term flexibility.
| Feature | Fixed Platform | Removable Platform |
|---|---|---|
| Structural rigidity | Excellent | Good (with quality anchors) |
| Cargo flexibility | None | Full (when removed) |
| Build complexity | Lower | Moderate |
| Resale impact | Permanent modification | Removable, vehicle restored |
| Typical material cost | $800 -- $1,400 | $1,000 -- $1,800 |
| DIY skill required | Basic carpentry or welding | Intermediate carpentry |
Materials and Tools You Will Need
For a timber-frame removable platform -- the most popular DIY choice -- gather the following before you start cutting.
For the frame, you will need 90x45mm hardwood (jarrah, spotted gum, or treated pine) for primary longitudinal rails -- approximately 12 linear metres. Cross members can step down to 70x45mm, and you will need roughly 8 metres. For the sleeping surface, two sheets of 18mm marine-grade plywood at 1,220x2,440mm each covers most builds, with offcuts for shelving. If you plan drawers, add 16mm MDF or additional ply for drawer boxes.
Hardware requirements include M12 coach bolts (minimum grade 8.8) for anchor points, 100mm timber screws for frame joinery, 75mm structural nails or screws for cross members, steel angle brackets (50x50x5mm) for frame corners, and quick-release clevis pins if the platform is removable. Budget for sandpaper, polyurethane sealant, and paint or carpet for finishing.
Tools needed include a circular saw or drop saw, cordless drill with timber and metal bits, measuring tape, spirit level, clamps, and a jigsaw for cutting around wheel arch profiles. Steel builds additionally require a MIG welder or access to a fabricator.
Step 1 -- Measure and Create Your Floor Plan
With the troopy empty and on level ground, take measurements at multiple points along the cargo floor. The floor is not perfectly flat -- it has a slight crown and the rear step area is recessed relative to the main cargo surface. Map both the floor contours and the wheel arch profiles on paper or in a basic CAD tool before drawing your final design.
Mark the exact position of the wheel arches on your floor plan. Measure how far they intrude horizontally (typically 90-100mm per side) and note their height at the innermost point. Your frame legs need to either sit outside these intrusions or the platform edge needs to step over them.
Decide on your platform height. For a standard-roof troopy, 400mm is the recommended target. This sits your platform surface just above the top of the wheel arches, allowing the sleeping surface to run full-width. Go lower than 380mm and you lose useful storage height beneath. Go above 440mm and headroom with a mattress becomes problematic.
Step 2 -- Build the Main Frame
Cut your two main longitudinal rails first. These run the full length of the platform -- approximately 2,200mm for a full-length bed that stops short of the rear door seal. Cut them to match your measured cargo bay length minus 80mm to allow clearance at front and rear.
The longitudinal rails form the backbone. Space them 1,580-1,620mm apart to match the inside of the wheel arches. Cross members sit between the rails at 400mm intervals, dadoed or bracketed in place. At each cross member, add a vertical leg timed to your target platform height. Brace each leg diagonally to prevent racking, using 45x45mm timber cut at 45 degrees and screwed into both the leg and the longitudinal rail.
Test the frame in the vehicle before adding the sleeping surface. Check that it sits level, all legs contact the floor evenly, and no leg is bridging a raised floor section. Shim legs as needed. The completed frame should feel solid with no flex when you push down hard on any corner.
Step 3 -- Handle the Wheel Arches
This is the part that trips up most first-time builders. There are two clean solutions. The first is to set your platform height at or above the top of the wheel arch -- typically 420-450mm -- so the sleeping surface runs clear over the arch completely. This delivers the flattest, most comfortable sleeping surface but reduces under-platform storage height near the rear.
The second approach steps the platform. The main sleeping area runs at 380mm forward of the arches, with the rear section dropping to 280mm to sit below the arch profile. The lower rear section can be used for a pull-out drawer, a flip-down access hatch, or a seat for someone working inside the vehicle. A diagonal brace connects the high and low sections, and the sleeping mattress either steps down to match or is cut to fit the full-height area only.
Whichever approach you choose, trace the wheel arch profile onto a piece of cardboard first and use that template to cut any timber that needs to sit close to the arch. A 10mm clearance between timber and the arch face is the minimum -- allow for flex and movement over rough terrain.
Step 4 -- Install the Sleeping Surface
Once the frame is confirmed level and solid, cut your 18mm marine ply to fit the sleeping surface. Do not fix the ply permanently. Instead, use timber battens screwed to the top of the frame cross members, creating a channel that holds the ply sheets in place without glue or permanent fasteners. This allows you to remove, flip, or replace the ply as needed.
Seal all cut edges of the plywood with two coats of exterior polyurethane before installation. Pay attention to end grain, which absorbs moisture fastest. Sand lightly between coats. The plywood surface can be left bare for a swag or foam mattress, carpeted with marine carpet for a finished look, or lined with non-slip rubber matting to prevent mattress movement overnight.
Join sheets of ply at a cross member, not mid-span. Each sheet should have full support underneath its join point, with the cross member centred directly beneath the joint line. Stagger joins left-to-right if using more than two sheets in width.
Step 5 -- Anchor the Platform Securely
A removable platform needs four anchor points minimum: two at the front and two at the rear. For each anchor, weld or bolt a 100x100x6mm steel plate to the cargo floor (after removing any factory carpet or rubber). This spreads the load across a larger floor area and prevents the M12 bolt from cracking thin sheet metal.
Through-bolt each anchor plate using M12 bolts with large-area washers on both sides. Access the underside of the floor from beneath the vehicle to fit the backing nut and washer. Apply thread locker to prevent vibration-related loosening over time.
For quick-release operation, weld or bolt a steel receiver tube to each anchor plate, then fabricate matching lugs on the bottom of the platform frame. A 12mm diameter stainless steel clevis pin slides through both to lock the platform down. Pull the pins, lift the platform out. Re-insert the pins, and the platform is secured for driving. This system takes under two minutes to engage or disengage.
Step 6 -- Build Storage Below the Platform
The space beneath a 400mm platform gives you 320-340mm of clear internal height after accounting for frame members -- enough for shallow drawers, jerry can mounts, or a fixed battery box. Plan your storage layout before the platform goes in, not after.
Slide-out drawers on 40kg-rated full-extension drawer slides are the most popular choice. A lateral drawer spanning the full width of the cargo bay (1,580mm) provides excellent storage volume for clothes, tools, or kitchen gear. Build drawer boxes from 16mm MDF or ply, with 19mm face frames. Use soft-close drawer slides to prevent slamming on rough terrain and ensure the drawer front is flush with the platform edge to prevent dust ingress.
Alternatively, the space beneath can be used for fixed compartments accessible from outside the vehicle. Bolt-on access panels in the side of the platform, sealed with compression latches, allow you to retrieve gear from outside without opening the rear doors -- useful in rain or when the tailgate is blocked by a loaded trailer.
Step 7 -- Finishing and Comfort
A raw timber platform works, but a finished one lasts considerably longer and looks far more professional. Sand the entire frame with 80-grit paper, follow with 120-grit, and apply two coats of exterior polyurethane or a two-pack epoxy paint. For the sleeping surface, carpet or marine vinyl laid over the ply improves comfort and protects the surface from abrasion.
Interior wall lining alongside the platform reduces condensation and heat loss significantly. Closed-cell foam (10-12mm) bonded to the inner cargo bay walls, covered with a fabric liner, creates a dry, insulated surface. Combined with a quality sleeping mat or foam mattress on the platform surface, this makes overnight temperatures noticeably more manageable in cold Australian conditions.
Ventilation is essential. Leave intentional air gaps between the platform edges and cargo bay walls -- 50mm minimum on each side. This airflow prevents moisture from being trapped beneath the mattress and slows the build-up of condensation that damages timber over time. Small 12V clip-on fans positioned at the head or foot of the bed improve airflow significantly on humid nights.
What Does a Troopy Bed Platform Cost?
A DIY timber build with quality materials costs $900-1,500 in timber, ply, hardware, anchor plates, and finishing products. Add $300-600 for a quality foam or self-inflating mattress. If you engage a professional fabricator to build a steel frame version with integrated drawers, expect $3,500-7,000 all-inclusive depending on complexity, drawer count, and finish quality.
The biggest variable is labour. If you can do the work yourself over a weekend, a highly capable timber platform is achievable for under $1,200. Steel builds with integrated cabinetry push costs significantly higher but deliver a showroom finish and superior long-term durability, particularly for vehicles that see heavy touring kilometres each year.
Frequently Asked Questions
What height should a Troopy sleeping platform be?
For a standard-roof 78 Series Troopy, 380-420mm is the recommended platform height. This sits the sleeping surface just above the wheel arch tops, allowing full-width coverage, while leaving 280-340mm of usable storage beneath the frame. Going higher than 440mm starts to create headroom issues once a mattress is added.
How wide can you build the sleeping platform in a Troopy?
The usable sleeping width is governed by the wheel arch intrusion. Between the arches, you typically have 1,580-1,650mm of clear space. Most platforms are built at 1,600mm wide, which is wide enough for two adults to sleep comfortably side-by-side. A platform wider than the arches requires notching or stepping at the rear to clear the arch profile.
Do I need to weld to build a Troopy bed platform?
No. A timber frame build requires only basic carpentry skills -- a saw, drill, and some patience. Welding is necessary only if you choose a steel frame design. Many owners use a hybrid approach: a steel anchor system and base frame welded by a fabricator, with timber interior components and ply sleeping surface built and fitted by themselves.
How long does a Troopy bed platform take to build?
A straightforward timber platform with a single-level sleeping surface takes most competent DIYers one to two weekends. This includes measuring, cutting, test-fitting, adjusting, finishing, and final installation. More complex builds with integrated drawers, stepped wheel arch sections, and carpeted finishes typically take three to four weekends of part-time work.
Will a Troopy bed platform affect my GVM?
Yes. A timber platform with ply and mattress typically weighs 100-160kg. This weight must be included in your GVM calculations alongside other modifications (roof rack, snorkel, water tanks, auxiliary battery). If you are close to your factory GVM limit, a GVM upgrade may be required before fitting a full bed setup.
Can the bed platform be used as a seat while driving?
Not legally in most Australian states without engineered and certified seat restraints. The rear cargo area of a Troopy is not certified as a passenger seating area in standard configuration. If you want to carry passengers in the cargo bay, a certified rear seat conversion with lap-sash seatbelts is required. The bed platform itself is not a substitute for engineered seating.
