Choosing the Right Materials for Blocking and Cribbing: A Safety Guide

Blocking and cribbing are two basic but critical tasks in many industries, especially construction, emergency rescue, rigging, and heavy equipment work. The purpose is simple: support heavy objects safely while work is being done. But choosing the right material for cribbing blocks is where things often go wrong.

This guide explains how to pick between wood, plastic, or composite cribbing, how to check load ratings, and what to look for during inspections. With the right materials and habits, you reduce the risk of collapse, injury, or fatal accidents.

What Is Cribbing?

Cribbing means stacking blocks to support or stabilize a heavy object like a vehicle, machine, or structure. It’s used during lifting, moving, or securing loads.

Blocking is similar but usually involves placing a solid object under a load to hold it in a fixed position.

Why Material Choice Matters

Not all blocks are the same. The material you choose affects:

• How much weight it can hold
  
• How it reacts to pressure, heat, moisture, and time
  
• Whether it cracks, breaks, slips, or holds firm
  

Choosing the wrong type of cribbing can cause the stack to collapse, even if it looks stable at first.

Material Options: Pros and Cons

Let’s break down the three most common types of cribbing materials.

1. Wood Cribbing

Wood has been used for decades, especially hardwoods like oak or ash.

Pros:

• Easy to find
  
• Inexpensive
  
• Good grip, less likely to slip
  

Cons:

• Can absorb water and rot
  
• Weakens over time
  
• Easily damaged by oil or chemicals
  
• Can splinter or crush if overloaded
  

Best for: Temporary use, dry environments, light to moderate loads.

2. Plastic Cribbing (Recycled HDPE)

Plastic cribbing is often made from high-density polyethylene (HDPE).

Pros:

• Water and chemical resistant
  
• Won’t rot or splinter
  
• Lightweight
  
• Long-lasting
  

Cons:

• Can be slippery
  
• May deform under heat
  
• Costs more than wood
  

Best for: Outdoor use, oily or wet conditions, moderate to heavy loads.

3. Composite Cribbing

Composite cribbing combines plastic with rubber, fiberglass, or other fillers.

Pros:

• Stronger than plastic alone
  
• Resists crushing under pressure
  
• Handles heat better
  
• Long service life
  

Cons:

• Expensive
  
• Can still be slippery if wet
  

Best for: Long-term use, rescue operations, high loads, hot or dirty environments.

Step-by-Step: How to Choose the Right Cribbing Material

Here’s a simple process to follow:

Step 1: Know Your Load

Find out the total weight the cribbing needs to support. Add extra for safety.

💡 Tip: A loaded truck or equipment often weighs more than people estimate.

Step 2: Check the Cribbing Load Rating

Every block type should have a load rating, usually in tons. Match it to your task.

• Look for Crush Rating (how much weight before it fails)
  
• Check Working Load Limit (WLL), which is the safe weight it can handle
  

Don’t guess, use the manufacturer’s numbers.

Step 3: Choose the Material Based on Conditions

Use this checklist:

Step 4: Inspect the Cribbing Before Every Use

Don’t use any block until it passes a quick check. Look for:

• Cracks or splits
  
• Mushrooming (ends flaring out under load)
  
• Burn marks or chemical stains
  
• Bent or twisted shapes
  
• Soft spots in wood (could mean rot)
  

Damaged blocks should be marked “DO NOT USE” and taken out of service.

Step 5: Use the Right Cribbing Stack Pattern

How you stack blocks is just as important as the material.

• Use a box or pyramid style for better balance
  
• Keep stacks level and centered under the load
  
• Avoid tilting or uneven pressure
  
• Never stack different materials together (like wood on plastic)
  

Safety Reminders for Cribbing Work

• Never stand or place body parts under a load supported only by cribbing
  
• Use wedges or shims to reduce movement
  
• Place cribbing on stable ground, no soft soil or uneven concrete
  
• Always have two or more contact points when lifting loads
  

Even the best material can fail if used the wrong way.

When to Replace Cribbing

Cribbing blocks don’t last forever. Here are some signs it’s time to replace them:

• The block is warped or twisted
  
• You see deep cuts or missing pieces
  
• Load markings are no longer visible
  
• Block wobbles or rocks when placed on a flat surface
  
• You can press it and feel it flex (especially plastic or wood)
  

Keeping damaged blocks “just in case” is not worth the risk.

Storage and Care Tips

• Keep cribbing clean and dry
  
• Store off the ground to avoid water damage
  
• Don’t stack too high, blocks at the bottom can deform
  
• Mark cribbing by type and load rating with color or labels
  
• Rotate blocks in use to prevent wear on the same ends
  

Proper care adds years to the life of your cribbing, and keeps workers safe.

Cribbing Accessories That Help

To improve safety and ease of use, you can add:

• Carrying handles for fast deployment
  
• Anti-slip mats or rubber pads between layers
  
• Color coding for size and material
  
• Wedges and spacers for leveling
  

These small extras can make a big difference when time is short and loads are heavy.

Final Thoughts

Choosing the right cribbing isn’t just about following a checklist. It’s about thinking ahead, knowing your tools, and respecting the load.

Wood may work for some jobs, but modern plastic and composite cribbing give you better strength and durability, especially in tough environments.

Whether you’re lifting a machine, stabilizing a vehicle, or responding to an emergency, your blocks are the foundation of safety. Pick them carefully, use them wisely, and inspect them often.

Your crew’s life could depend on it.