Under Caravan Protection Guide
Everything hidden beneath your caravan is at risk on gravel roads — water tanks, brake lines, wiring, and plumbing. Here's how to protect it all.
All Guides
Protection Checklist
Every area of your caravan covered.
Installation Guide
Step-by-step stone guard fitting instructions.
Gravel Road Prep
Prepare for unsealed roads and outback tracks.
Off-Road Caravan Guide
Prepare your off-road caravan for outback tracks.
Best Tow Vehicle
Choose a tow vehicle and protect it from stones.
Best Accessories
Essential accessories for Australian caravan travel.
Mud Flaps vs Stone Guards
Coverage, cost and convenience compared.
Window Protection
Protect caravan windows from stone damage.
Under Caravan Protection
Protect undercarriage, belly pan and chassis.
DIY Stone Guard
DIY approaches vs commercial stone guards.
Outback Trip Checklist
Everything you need for outback caravan travel.
Tow Vehicle Stone Guard
Protect your tow vehicle from rear stone damage.
What's at Risk Underneath Your Caravan
The underside of a caravan carries critical systems that are directly exposed to road debris. On gravel roads, stones thrown upward by the caravan's own axle-mounted tyres bombard these components from below:
Fresh Water Tanks
Typically poly or stainless steel, mounted under the floor. Stone strikes can crack poly tanks or dent stainless, causing slow leaks that go unnoticed until the tank runs dry.
Grey Water Tank
Usually thinner-walled than fresh water tanks and equally exposed. A cracked grey water tank leaks waste water across camp sites and along roads.
Brake Lines & Cables
Hydraulic brake lines and electric brake wiring run along the chassis. A severed brake line means no trailer brakes — extremely dangerous on steep descents.
Electrical Wiring Looms
12V and 240V wiring, Anderson plug cables, and solar panel feeds often run under the floor. Stone damage can cause short circuits, blown fuses, or fire risk.
Gas Lines
Copper or rubber gas lines connecting bottles to appliances run along the chassis and through the floor. A damaged gas line is a serious fire and explosion hazard.
Plumbing Connections
Water pump, hot water service inlet/outlet, and waste pipe connections are all vulnerable to impact. Even a loosened fitting causes drips that lead to floor rot.
Types of Underbody Protection
Belly Pans (Underbody Shields)
A full-length caravan belly pan is a sheet of corrugated aluminium, composite, or corflute that covers the entire underside of the caravan floor. It provides comprehensive protection against stone strikes and also prevents dust and water intrusion into underbody cavities.
Cost: $500-$2,000 for aftermarket fitting. Factory-fitted on most off-road caravans.
Bash Plates
Heavy-duty aluminium or steel plates bolted over specific vulnerable areas — typically water tanks, gas bottle mounts, and the A-frame underside. Bash plates are thicker and stronger than belly pans and designed to withstand direct rock impacts on rough 4WD tracks.
Cost: $150-$500 per plate depending on size and material.
Stone Tape (Anti-Chip Tape)
Thick adhesive tape applied to chassis rails, exposed pipes, and wiring conduit. Brands like Tesa and 3M produce heavy-duty stone chip tape rated for automotive and caravan use. It's cheap, easy to apply, and effective for protecting specific components like brake lines and gas pipes.
Cost: $15-$40 per roll. Easy DIY application.
Spray-On Coatings
Rubberised underbody coatings (Shutz, 3M Underseal, Wurth) sprayed onto the chassis and underbody panels. They provide corrosion resistance and moderate stone chip protection. Best applied to a clean, prepared chassis by a professional. Not a substitute for bash plates on rough tracks but excellent for highway and light gravel touring.
Cost: $200-$600 for professional application.
Wiring Conduit & Pipe Protection
All exposed wiring and pipes should run through corrugated split conduit (minimum 20mm diameter). This protects against stone impacts, abrasion from road vibration, and rodent damage. Stainless steel conduit clips prevent movement and chafing.
Cost: $20-$80 for a full caravan rewrap in conduit.
How A-Frame Stone Guards Complement Underbody Protection
An A-frame stone guard like the D-Flector (rated 9.3/10) is your first line of underbody defence. It intercepts the highest-velocity stones — those thrown rearward by the tow vehicle — before they can pass under the caravan and strike water tanks, brake lines, or wiring from below.
Think of protection as layered: the stone guard handles the forward barrage from the tow vehicle, while belly pans and bash plates handle stones thrown upward by the caravan's own tyres and road debris kicked up from the sides. Neither system alone provides complete under caravan protection — you need both for serious gravel road touring.
For a full breakdown of stone guard options, see our comparison chart and stone guard reviews.
Underbody Protection Maintenance Checklist
Run through this checklist before every trip and after extended gravel road driving:
Inspect Stone Guard
Check mesh for tears, mounting bolts for tightness, and frame for corrosion. The D-Flector's stainless steel frame needs minimal maintenance.
Check Belly Pan Fixings
Vibration on corrugated roads loosens rivets and screws. Re-fasten or replace any loose fixings. Look for sagging sections.
Inspect Water Tanks
Look for cracks, dents, and leaks. Check mounting straps are tight. Test tank level sensors.
Check Brake Lines
Visually inspect hydraulic lines for chafing, dents, or leaks. Check electric brake wiring connections are secure and conduit is intact.
Inspect Gas Lines
Check all gas line connections with leak detection spray. Look for stone damage on copper pipes. Ensure protective conduit is intact.
Check Wiring Conduit
Ensure all wiring runs through conduit with no exposed sections. Replace any cracked or split conduit immediately.
Inspect Chassis Coating
If spray-coated, look for chips or bare metal patches. Touch up with matching underbody spray to prevent corrosion.
Clean Underbody After Gravel
Wash the underside with fresh water after gravel road trips to remove dust, salt, and trapped debris that accelerates corrosion.
For a comprehensive pre-trip list, see our Complete Caravan Protection Checklist.
Under Caravan Protection FAQs
What is under my caravan that needs protection?
The underside of a caravan contains critical components that are vulnerable to stone damage: fresh water tanks, grey water tanks, brake lines, electrical wiring looms, gas lines, the chassis itself, and plumbing connections. On gravel roads, stones thrown upward by the caravan's own tyres can damage all of these components, leading to leaks, electrical faults, or brake failure.
What is the best underbody protection for a caravan?
The best approach is layered protection: an A-frame stone guard (like the D-Flector, rated 9.3/10) to intercept forward-thrown stones, a corrugated aluminium or composite belly pan to shield the undercarriage floor, and bash plates over exposed water tanks and fittings. For the chassis itself, a spray-on protective coating like Underbody Shield or Shutz provides additional corrosion and impact resistance.
Do I need a belly pan on my caravan?
If you travel on gravel roads or unsealed tracks, a belly pan is highly recommended. It protects water tanks, wiring, and plumbing from stone strikes, prevents dust intrusion into underbody cavities, and adds a layer of insulation. Most quality off-road caravans include a belly pan from the factory, but it can be retrofitted to touring caravans for $500-$2,000 depending on size and material.
How does a stone guard help protect the undercarriage?
An A-frame stone guard like the D-Flector intercepts stones thrown rearward by the tow vehicle before they reach the caravan. This dramatically reduces the volume of stones that pass under the caravan's floor. Without a stone guard, the full barrage of road stones hits the front panel and deflects downward and underneath, bombarding water tanks, brake lines, and wiring.
Start With A-Frame Protection
An A-frame stone guard is the first step in any underbody protection plan. Compare all options and find the right fit.