Plywood vs MDF: Which is Better for Your Van Build?
Plywood and MDF are the two most common board materials for campervan furniture. This guide compares them on weight, moisture resistance, strength, cost, and workability for UK van builds.
The Short Answer
Use plywood for everything. It is lighter, stronger, and handles moisture better than MDF. The only reason to use MDF is if you are on a very tight budget and your van stays bone dry.
Weight Comparison
| Material | Weight per m² (18mm) | Weight for a full van build |
|---|---|---|
| Birch plywood | 11 kg/m² | 150-250kg (typical LWB van) |
| Marine plywood | 13 kg/m² | 200-300kg |
| MDF | 15 kg/m² | 250-350kg |
| OSB (oriented strand) | 9 kg/m² | 120-200kg |
| OSB is lighter but splinters and has poor moisture resistance |
Van payload matters. A typical LWB van has a payload of 800-1,200kg. MDF adds 100kg more weight than birch ply for the same build — that is 10% of your available payload eaten by board choice alone.
Moisture Resistance
| Material | Moisture Rating | Swell in 24h (soaked) | Best Use |
|---|---|---|---|
| Marine ply (WBP) | Excellent | 5-8% | Wet areas, floors |
| Birch ply (WBP) | Good | 8-12% | General furniture |
| MR-MDF | Moisture resistant | 15-20% | Dry indoor use |
| Standard MDF | Poor | 25-40% (disintegrates) | Do not use in vans |
The MDF problem: Standard MDF is made from wood fibres bonded with urea-formaldehyde resin. When it gets wet, the fibres swell to multiple times their original thickness, the board delaminates, and it turns to sawdust. In a van environment where humidity regularly reaches 70-80%, MDF will swell at edges, around screw holes, and anywhere the surface coating is scratched.
Moisture Reality in UK Vans
Average interior relative humidity in a UK campervan:
- Summer (ventilated): 50-60%
- Winter (condensation period): 65-85%
- After cooking / showering: 80-95% temporarily
Standard MDF degrades permanently above 65% RH. MR-MDF handles up to 80%. Only marine or birch ply handles the full range.
Strength Comparison
| Property | Birch Ply (18mm) | MDF (18mm) |
|---|---|---|
| Flexural strength | 60 MPa | 20 MPa |
| Screw holding | 1,200 N | 400 N |
| Impact resistance | High | Low (cracks) |
| Creep over time | Minimal | Sags |
Results: Plywood is 3x stronger and holds screws 3x better. MDF cracks under impact and cannot hold screws securely after one disassembly.
In a van where furniture flexes as the van goes over bumps and corners, MDF joints will work loose over a few thousand miles. Plywood joints stay tight.
Cost Comparison
| Material (18mm, 2440x1220mm sheet) | Price per sheet | Full van cost |
|---|---|---|
| Standard MDF | £25-35 | £200-350 |
| MR-MDF | £35-50 | £300-500 |
| Birch plywood | £55-80 | £550-800 |
| Marine plywood | £80-120 | £800-1,200 |
Value for money: Birch ply costs about double standard MDF per sheet. But it weighs less, lasts 5x longer in moist conditions, and your furniture will not need rebuilding in 3 years.
Workability
| Task | Plywood | MDF |
|---|---|---|
| Cutting (circular saw) | Smooth edge, no chipping | Dust, sharp edge |
| Routing | Clean | Very clean (best for routed edges) |
| Sanding | Needs sealer first | Smooth finish easily |
| Painting | Requires primer + several coats | Takes paint well, needs sealing edges |
| Screwing | Harder to drive screws | Easier to drive but strips easily |
| Gluing | PVA works | PVA works but absorbs into fibres |
MDF wins on routed edges and painted finishes. Plywood wins on everything else.
Verdict by Application
| Van Component | Best Material | Runner Up |
|---|---|---|
| Bed base / platform | Birch ply 18mm | Marine ply |
| Kitchen cabinets | Birch ply 12-15mm | Marine ply |
| Wall panels | Birch ply 6-9mm | -- |
| Ceiling panels | Birch ply 4-6mm | -- |
| Doors (cabinet) | Birch ply 12mm | MDF (if painted) |
| Floor | Marine ply 12-18mm | Birch ply with good sealing |
| Table | Birch ply 18mm (lightweight) | Marine ply |
| Wheel arch boxes | Marine ply 12mm | Birch ply with sealing |
When You Could Use MDF
- Light-use summer van: If your van is used only in dry weather and stored in a garage, MR-MDF could survive
- Painted cabinet doors: MDF gives a smoother paint finish for doors that are well-sealed
- Templates: MDF is cheap for making template shapes before cutting the final piece in ply
Sealing Tips for Plywood
Even birch ply needs edge sealing in a van:
- Sand all cut edges smooth
- Apply two coats of exterior-grade wood sealer or PVA glue thinned 50:50 with water
- Paint or varnish with moisture-resistant coating
- Pay special attention to cutouts for hinges and handles
Conclusion
Plywood is the right choice for campervan furniture. It handles moisture, holds screws, stays strong through temperature cycles, and preserves your van's payload. The extra cost (£300-500 vs MDF for a full build) is justified by longevity.
Our recommendation: Use 18mm birch ply for structural elements (bed, cabinets) and 6-9mm birch ply for wall and ceiling panels. Seal all cut edges. Skip the MDF entirely.
