LWB Campervan Garage & Shower Room Layout: Design Guide for Long Wheelbase Vans
If you need a shower inside your van and space for bikes or surfboards, a long wheelbase van with a rear garage and mid-mounted bathroom is the layout you are looking for. It is the most versatile layout for full-time living, but it demands careful design to avoid wasting the extra length.
I built this layout in a Mercedes Sprinter L3H2. The garage swallowed two mountain bikes, camping chairs, and a table. The shower room had a cassette toilet and a removable shower tray. The living space was compact but comfortable. It was the best layout I have lived in — for my needs.
This guide covers the floor plans, dimensions, and build details for the garage + shower room layout, including the compromises you make for each van size.
Why This Layout Works
The garage + mid-bathroom layout gives you:
- Wet gear separation: Muddy bikes, wet wetsuits, and dirty boots live in the garage, not the living space
- Shower access from outside: The bathroom is positioned so you can use it from the side door without walking through the van
- Flexible rear: The garage can be a workshop, dog area, gear store, or extra sleeping space
- Fixed bed: The bed is above the cab or in a fixed position — no conversion needed
Van Requirements
| Van | Minimum Length | Garage Length | Shower Room | Living Space |
|---|---|---|---|---|
| Transit Custom L2 (5.3m) | 2.6m cargo | 600mm | 700mm | 1,300mm — tight |
| Sprinter L2 (6.0m) | 3.2m cargo | 900mm | 800mm | 1,500mm — comfortable |
| Sprinter L3 (6.9m) | 3.7m cargo | 1,200mm | 900mm | 1,600mm — generous |
| Ducato L3 (6.0m) | 3.1m cargo | 900mm | 800mm | 1,400mm — comfortable |
| Ducato L4 (6.6m) | 3.7m cargo | 1,200mm | 900mm | 1,600mm — generous |
Verdict: You need an L2 Sprinter / L3 Ducato (6.0m+) for a comfortable garage + shower room layout. Anything smaller and the living space becomes cramped.
The Classic Layout: Mid Bathroom + Rear Garage
┌─────────────────────────────────────────────────┐
│ CAB │ LIVING / KITCHEN │ BATHROOM │GARAGE│
│ │ ┌──┬──┬──┬──┬──┬──┐ │ ┌──┬──┐ │ │
│ ║ │ │K │K │K │K │D │D │ │ │WC│SH│ │BIKES │
│ ║ │ │I │I │I │I │E │E │ │ │ │ │ │ │
│ ║ │ │T │T │T │T │S │S │ │ │ │ │ │GEAR │
│ ║ │ └──┴──┴──┴──┴──┴──┘ │ └──┴──┘ │ │
│ ║ │ BENCH / TABLE │ │ │
│ │ │ │ │
└─────────────────────────────────────────────────┘
Key dimensions (Sprinter L3, 6.9m overall):
- Garage: 1,200mm (rear) — enough for two bikes side by side
- Shower room: 900mm (mid, behind passenger cab)
- Kitchen: 1,600mm (mid, behind driver cab)
- Lounge: 1,600mm (between kitchen and bathroom)
- Cab: Not included in cargo length
Flow
The bathroom is positioned behind the passenger cab, accessible from the sliding door. This means:
- You can shower without walking through the living space
- The bathroom door opens without hitting the kitchen
- You can access the bathroom from outside (good for rinsing after the beach)
- The bathroom wall acts as the rear of the living space, creating a defined bedroom/garage zone
Layout Option 1: Side Garage, Full Bathroom
In this layout, the garage is on one side of the rear and the bathroom is full-width.
| Zone | Width | Length | Features |
|---|---|---|---|
| Garage (passenger side rear) | 800mm | 1,800mm | Bike storage, gear, external access |
| Bathroom (driver side rear) | Full width | 900mm | Shower tray, cassette toilet, basin |
| Kitchen (mid, driver side) | 1,800mm | 600mm | Sink, hob, worktop, fridge |
| Lounge (mid, passenger side) | 1,000mm | 1,800mm | Bench seat, table, swivel cab seat |
Pros: Full-size shower room, generous garage, good separation of wet/dry zones Cons: The living space is narrower (a corridor layout), less flexible for guests Best for: Couples, van lifers who shower daily, mountain bikers
Building the Garage Wall
The wall between the garage and living space needs careful construction:
- Soundproofing: 25mm of closed-cell foam + mass-loaded vinyl between two layers of plywood
- Moisture barrier: A vapour barrier on the living space side (garage humidity must not reach the living space)
- Access hatch: A 400mm × 400mm hatch from the living space into the garage for loading through the cab
- Rear door access: Both rear doors open to the garage — fit separate door catches so the garage can be locked from outside
Garage Floor
The garage floor takes a beating. Build it with:
- 12mm marine ply (not standard ply — it delaminates with moisture)
- Painted with garage floor paint (non-slip additive)
- A drain point (drill a 20mm hole, fit a plug, drain to outside for washing out the garage)
- Tie-down points (D-rings bolted through the floor for bikes and gear)
Layout Option 2: Wet Room + Garage (Full Width)
In this layout, the bathroom spans the full width, and the garage is a shallow rear section.
| Zone | Width | Length | Features |
|---|---|---|---|
| Full wet room (mid) | 1,800mm | 900mm | Shower + toilet + basin in one room |
| Garage (rear) | Full width | 700mm | Bike storage, access from rear doors |
| Kitchen (front, driver side) | 600mm | 1,200mm | Compact kitchen |
| Lounge (front, passenger side) | 1,200mm | 1,600mm | Bench, table, swivel seat |
Pros: Full standing-height shower room, generous bathroom, simple build Cons: Shallow garage — only fits one bike or gear, not both Best for: Couples who want a proper shower, light gear load
Building a Wet Room
A wet room (open shower within the bathroom, no separate shower tray) saves space but requires:
- Full tanking: The entire bathroom floor and lower 500mm of walls must be tanked with a waterproof membrane (Mapei, BAL, or similar)
- Slopped floor: The floor must slope to a drain (minimum 2° fall)
- Drain: A 12V macerator pump (Rule or Whale) pumps grey water to the under-van tank, or a gravity drain if the tank is under the van
- Ventilation: A 12V extractor fan is essential. Without it, the wet room becomes a condensation machine
Layout Option 3: Convertible Garage/Bedroom
This layout has a high garage that doubles as a second bedroom.
| Zone | Width | Length | Features |
|---|---|---|---|
| Garage (rear, lower level) | Full width | 1,200mm | Bike storage, gear |
| Drop-down bed (rear, upper level) | Full width | 1,200mm | Over the garage, accessible from living space |
| Bathroom (mid) | 900mm | 800mm | Compact wet room |
| Kitchen (mid) | 900mm | 1,800mm | Full kitchen |
| Lounge (front) | 1,200mm | 1,200mm | Bench, swivel seats |
Best for: Families (the over-garage bed is ideal for a child), people who need both bikes and a guest bed
Important: The garage height must be at least 800mm for bike storage. The bed height above must have at least 600mm of headroom. This only works in high roof vans (Sprinter H2, Ducato high roof).
Shower Room Design
Shower Tray vs Wet Room
| Option | Cost | Space Needed | Pros | Cons |
|---|---|---|---|---|
| Shower tray | £50–150 | 700mm × 700mm | Simple install, contained water | Takes floor space |
| Wet room | £100–300 | 800mm × 800mm | No tray to step over | Complex waterproofing |
| External shower | £30–80 | None | Simple, no space inside | Cold weather, privacy |
| Pull-out shower (kitchen tap) | £15–25 | None | Cheap, doubles as kitchen | Cramped, splashy |
Water Heating for Showers
| Method | Cost | Hot Water | Best For |
|---|---|---|---|
| Engine heat exchanger | £60–120 | While driving | Most practical UK option |
| Gas water heater (Truma) | £400–700 | Unlimited | Professional builds |
| Kettle + mixing valve | £10 | Limited | Budget builds |
| Immersion heater 12V | £100–150 | 5L tank | Small systems |
| Diesel heater + heat exchanger | £800–1,200 | Cabin heat + hot water | Premium build |
Grey Water
Your shower produces 10–20L of grey water per shower. You need:
- A 30–50L grey water tank mounted under the van
- A 20mm waste hose from the shower drain to the tank
- A dump valve (cable-operated so you can open it from the side of the van)
- A filter (shower hair clogs small pipes — fit a simple mesh filter at the drain)
Garage Design
Floor
- 12mm marine ply with garage floor paint
- Non-slip additive (sanded paint or grip tape strips)
- Drain point at the lowest corner
Bike Storage
- Vertical mount: Bikes hang from the ceiling on fork mounts. Best space usage but bikes are hard to lift in.
- Horizontal mount: Bikes sit on the floor between wheel chocks. Easier load but takes floor space.
- Roller drawer: Bikes in a slide-out tray. Excellent access but adds complexity and weight.
For most people, horizontal floor-mounted wheel chocks + a ceiling-mounted front wheel hook is the sweet spot. Two bikes fit in a 1,200mm × 800mm footprint.
Lighting and Power
- LED strip lights around the garage perimeter (12V, switched from cab and rear)
- A 12V socket for charging e-bike batteries (in a fire-proof charging bag)
- Motion-sensor light for gear access at night
Insulation and Ventilation
The garage and bathroom need different insulation strategies than the living space.
Garage
- Less insulation required (gear does not need warmth)
- But: insulated from the living space wall (to prevent cold bridging)
- Ventilated: a 50mm vent to the outside (prevents mould on wet gear)
Bathroom
- Fully insulated walls and ceiling (you shower in here)
- vapour barrier on the inside (behind the wall finish)
- 12V extractor fan vented through the roof
- Heated towel rail or diesel heater vent (dries towels, takes chill off the room)
FAQ
Q: Can I fit a garage and shower in a Transit Custom? A: Barely. The L2 Custom has 2.6m of cargo length. A garage of 600mm + shower room of 700mm leaves 1,300mm for living space. It is tight but doable if you use a cab bed. A better option for this layout is a Sprinter L2 or Ducato L3.
Q: How much does a garage + shower room layout cost to build? A: The bathroom alone adds £500–1,500 (tanking, shower tray, toilet, plumbing). The garage wall adds £200–400 (framing, soundproofing, hatch). Total additional cost over a simple layout: £800–2,000.
Q: Do I need planning permission for a campervan shower? A: No. You are converting a vehicle, not a building. No planning permission required.
Q: How do I stop the shower room getting mouldy? A: Install a 12V extractor fan that runs for 15 minutes after the shower. Wipe down the walls after every shower. Use a squeegee on the walls and a microfibre towel on the floor. Leave the bathroom door open to air out.
Q: Can I stand up in the shower? A: Only in a high roof van (Sprinter H2, Ducato high roof) or if the shower is in the centre of the van where the roof is highest. In a standard roof Transit Custom, you shower sitting down or bent over.
Q: Does a garage + shower layout reduce payload significantly? A: Yes. The bathroom (walls, tray, toilet, plumbing, water) adds 80–120kg. The garage wall and floor add 30–50kg. If you are already close to your GVW, this layout may push you over.
