Wooden pallets are everywhere in UK warehouses and shipping yards. But if you store or use them outdoors, you might wonder: are wooden pallets actually waterproof?
The short answer is no. Standard wooden pallets are not waterproof. However, they do have some natural water resistance, and there are several ways to protect them from moisture damage.
Understanding Wood and Water
Wood is a natural material that absorbs moisture. When untreated wooden pallets get wet, the timber soaks up water like a sponge. This leads to warping, swelling, rotting and mould growth.
How much water a pallet absorbs depends on the wood type, how dry it was beforehand, how long it stays wet, and whether it has any protective treatment. Most UK pallets are made from softwoods like pine or spruce. These are affordable but have lower natural water resistance than hardwoods.
Types of Wood and Their Water Resistance
Different woods handle moisture differently. Here is a comparison:
| Wood Type | Water Resistance | Notes |
|---|---|---|
| Pine | Low | Most common, needs treatment for wet conditions |
| Spruce | Low | Absorbs moisture quickly |
| Oak | Medium-High | Naturally more durable, higher cost |
| Cedar | High | Natural oils resist moisture and insects |
| Teak | Very High | Rarely used for pallets due to cost |
For most business uses, standard pine pallets work well in dry warehouses. For outdoor use or wet conditions, choose more resistant wood or apply waterproofing treatments.
How to Protect Wooden Pallets from Water Damage
If your pallets face rain, humidity or spillages, here are several ways to protect them:
Apply a waterproof sealant. Sealants create a barrier that stops water from soaking in. Apply to all surfaces, paying extra attention to end grain where water absorbs fastest.
Use waterproof paint or stain. Outdoor paints designed for decking work well on pallets. Multiple coats give better protection.
Cover pallets stored outdoors. Tarpaulins or roof cover keep the weather off. Ensure pallets can still breathe to prevent condensation.
Store pallets off the ground. Raising pallets stops them from sitting in puddles. Use blocks or a concrete base to keep airflow underneath.
Choose the right pallet grade. Grade A standard pallets are in excellent condition with intact surfaces that resist moisture better. Grade B standard pallets offer a good balance between cost and quality for most conditions.
Heat Treatment and Water Resistance
Heat-treated pallets (marked HT) are required for international shipping under ISPM 15 regulations. The process kills pests by heating pallets to 56°C for at least 30 minutes.
While heat treatment reduces moisture content initially, it does not make pallets permanently waterproof. Heat-treated pallets can still absorb water when exposed to rain. The main purpose is pest control, not waterproofing.
For guidance on safe timber treatment practices, the Health and Safety Executive provides information on their industrial timber treatment plants page.
Signs of Water Damage
Regular inspections help catch water damage early. Look for:
- Warping or bending boards
- Soft spots where wood feels spongy
- Dark patches or staining
- Mould or mildew growth
- Musty smell
- Loose nails pulling away
Pallets showing these signs should be removed from use. Damaged pallets can often be recycled rather than sent to a landfill.
Frequently Asked Questions
Can wooden pallets be left outside?
Yes, but they deteriorate faster without protection. Untreated pallets left outdoors typically last one to three years. Treated or covered pallets last longer.
How long does a wet pallet take to dry?
A soaking wet pallet can take several days to dry completely. Warm, dry weather with good airflow speeds this up.
Are plastic pallets better for wet conditions?
Plastic pallets are completely waterproof and ideal for wet environments. However, they cost more and are less environmentally friendly to produce.
Conclusion
Wooden pallets are not naturally waterproof, but with proper treatment, storage and maintenance, they provide reliable service even when exposed to moisture.
CM Pallets supplies quality pallets to suit different requirements. As a family-run business with over 20 years of experience serving London, Essex and Kent, we match the right pallet to the right job.
Contact us on 01375 767790 to discuss your pallet needs, with delivery guaranteed within 24 hours.
