The HiAce campervan conversion jobs that cost double if you do them last

Most of the money wasted on a HiAce campervan conversion goes on work done twice. Two rules decide what can sit behind your lining: the caravan and motorhome wiring standard in force since 18 November 2023, and a fit-out code written well before that. Build in the order they imply.

What order should I build a HiAce camper in?

Work outwards from bare metal: rust repair and roof penetrations first, then cable and water runs, then insulation, then lining, then furniture, then the fit-off. Each step buries the one before it, which is exactly why the order matters.

The temptation is to start with the bed, because it’s the part you can already picture. Resist it. A bed frame built before the wiring is planned gets drilled, unbolted and rebuilt around cable runs you didn’t allow for, and the second version is never as neat as the first.

The rules bite earliest at the design stage, not the build stage. Code LH11 in Vehicle Standards Bulletin 14, issued in this version on 1 January 2011, sets the minimum safety requirements for turning a vehicle into a campervan, and it asks two plain things of your interior. Fittings have to be shaped and positioned so nobody riding inside gets hurt by them, and seating, tables and gear all need fixing down firmly enough that ordinary driving won’t shake anything loose.

In practice that rules out sharp corners at head height, overhead lockers on brackets that were never meant to carry load, and a fridge held down by nothing but its own weight. Decide where things bolt to the van’s structure while you can still see the structure.

How do I stop condensation in a camper van?

You stop condensation by keeping warm, damp air off cold steel and giving that air a way out, which makes it a ventilation problem at least as much as an insulation one.

Two adults sleeping put a surprising volume of moisture into the air overnight, and cooking adds more. In a bare van that moisture finds the coldest surface available, which is the roof skin and the ribs, then runs down inside the walls where you never see it.

The order of defence is straightforward. Bond closed-cell foam directly to the panels so there’s no air gap for damp air to reach the steel, insulate the floor as well as the walls and roof, and fit a powered roof vent with a low intake somewhere else in the van. Bare plywood laid straight onto the floor pan is a cold bridge you will feel on the first frosty morning.

Avoid anything that holds water. Fibrous batts stuffed behind lining without a vapour barrier get wet, stay wet, and rust the van from the inside out. And never insulate over rust you haven’t treated, because the next time you meet it will be with a pry bar and a full interior to remove.

Will the HiAce still be legal once the bed, kitchen and water tank are in?

Only if the finished build, plus water, gear and passengers, stays under the Gross Vehicle Mass on the compliance plate, which is the maximum the van is allowed to weigh fully loaded.

Payload is what ends builds, and it is the one figure most first-timers never check. Start with GVM from the plate, subtract the van’s real weight across a weighbridge rather than the brochure number, then subtract everything you intend to add: timber, insulation, battery, tank, fridge, awning, roof rack, recovery gear and the people in the seats. Whatever is left is your luggage allowance.

Water is the heaviest item most people carry and the easiest to underestimate, because every litre aboard is another kilogram. Mounted behind the rear axle it also does the most damage to the way the van steers and stops. Under the floor and forward of the rear axle is kinder to both.

Fixing an overweight build by re-rating the van is harder than the forums suggest. The National Heavy Vehicle Regulator says only a narrow set of cases allows a motorhome’s rated mass to move up or down at all, and any re-rate has to be examined and signed off by an Approved Vehicle Examiner. Its motorhome guide covers conversions above 4.5 tonnes, so a HiAce falls outside it and your state or territory road authority sets the light-vehicle rules, but the principle carries: GVM is not a number you adjust with a spreadsheet.

If passengers will travel in the back, price the seat work before you cut any cabinetry. The NHVR counts fitting a new seatbelt, or swapping an old one, as a modification needing assessment and certification by an Approved Vehicle Examiner. It also says anchorage points for child restraints aren’t compulsory on a converted motorhome, while advising you fit them if kids will be riding along.

What do the current electrical rules mean for my van’s wiring?

If the van will ever plug into mains power at a caravan park, the installation has to meet AS/NZS 3001.2:2022, the standard governing any caravan, motorhome, camper trailer or slide-on unit able to draw power from a 230/240V hook-up. REDARC says the rules landed on 18 November 2023, at the end of a 12-month phase-in.

The clause that catches most builders is battery placement. Under the standard, lithium batteries are barred from the living space unless they sit inside a sealed box that vents out of the vehicle, according to REDARC, while a battery hung outside on the chassis escapes those conditions. A chassis-mounted battery therefore avoids a requirement the same battery triggers under the bed, which makes the under-floor position the simpler path if your layout allows it.

Two more points are worth knowing before you buy hardware, both from REDARC. Wiring finished before that November 2023 date is judged against whatever rules applied when the work was done. And switching from lead-acid to lithium counts as an alteration, so that job has to satisfy today’s standard rather than the one the van was first built under, which drags an older fit-out forward.

On the low-voltage side, the expensive mistakes are cable size and cable route. Run heavier cable than the calculator says, fuse close to the battery, leave the fridge and inverter room to breathe, and pull a spare draw string through every conduit before the lining goes back on. String costs nothing now and saves a wall later.

Which decisions are expensive to undo?

Anything behind the lining, through the roof, or fixed to the van’s structure. Everything else is a weekend.

These are the six worth agonising over before the first cut:

• Roof penetrations for a vent, hatch or solar, because a patched hole is a leak waiting for the right storm.
• Battery position, since moving a lithium battery out of the living area later means dismantling the cabinetry built around it.
• Cable and conduit routes, which cost almost nothing to add now and cost a stripped wall to add later.
• Fixing points welded or riveted to the body, because retro-fitting them means removing everything already bolted to that panel.
• Water tank position, which sets your weight distribution and can’t be changed without lifting the floor or the furniture.
• Seat and seatbelt changes, which need certification and are far cheaper to design in than to add.

Best for a first build: a modular fit-out that bolts to captive nuts and threaded plates rather than a glued and screwed carcass, so a layout you get wrong costs you a Saturday instead of the whole interior.

None of this makes the job harder. It moves the thinking to the front, where changing your mind is still free. Draw the layout, weigh the van, settle the battery and tank positions, then start cutting.