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Dos and Don’ts of Cribbing


wood cribbing construction

Cribbing (also called a “box crib”) is a popular practice for aerial lift operators, construction foreman and other job site workers, and is used in a variety of work situations. The process of construction cribbing involves building a temporary wooden structure to support heavy machinery, but it can be dangerous if workers don’t know the proper techniques for cribbing safely.

If you or your employees use cribbing in their work along with aerial lifts, knowing the basics of cribbing safely and preventing accidents involved with cribbing and large machinery can protect you and your workplace from serious injuries, fatalities, and costly equipment damage.

Wood Cribbing Construction 101

The use of cribbing is essential for many extrication operations. Its most common use is to stabilize large objects and heavy equipment. Wood cribbing construction materials should be solid and straight to avoid any slippage or instability. They should also be free from paint or finishes. Pieces of wood that are 2X2 and 4X4 are common for use with cribbing construction work.

The actual work of cribbing involves multiple pieces of wood that are laid on the side and crossed over each other. This technique spreads the load and creates multiple load transfer surfaces. This type of cribbing structure also offers lateral stability.

Here are a few basic rules for wood cribbing construction:

  • – The height should be no greater than three times the width
  • – The overhang at the corners should be no less than 4 inches
  • – The weight limit for a 4X4 cribbing structure is about 24,000 pounds, and for a 6X6 structure, it’s about 60,000 pounds.

How to Use Cribbing Construction Correctlyhow aerial lift operators use cribbing construction

Cribbing is used to help support an extra-large piece of industrial equipment, and other times it’s used to gain a better angle for hoisting or lifting materials. It’s also implemented to achieve better stability on otherwise unstable surfaces.

When selecting the materials for the wood cribbing construction, look for these qualities:

  • – Physically capable of handling heavy loads
  • – Absence of cracks, deformations, rot, bent, worn or damaged parts
  • – Larger in size than the foot of the outrigger
  • – Sufficient thickness, width and length to provide stability
  • – Absence of oil, grease or debris that can cause slippage

All workers involved in wood cribbing construction should have the following:

  • – Personal Protective Equipment, including steel-toed boots, gloves, and eye protection

The correct uses and methods of cribbing construction include:

  • – Set the cribbing materials on firm, level ground
  • – Make sure no debris is under the cribbing or blocking
  • – Place the cribbing structure directly beneath the outrigger
  • – Inspect the cribbing during operation
  • – Make sure the cribbing is no taller than twice the width of the blocking base

To calculate the correct blocking size to use, follow these rules:

  • Rule of 5 – take the maximum lifting capacity in tons of the unit and divide that by 5
  • Rule of 3 – take the square footage of the cranes floats and multiply that by 3

Wood Cribbing Worker Safety

For aerial lift operators, cribbing has to be undertaken with extra caution. Given the top-heavy loads and sheer height of some aerial lifts, wood cribbing construction should only be done with professional, certified supervision. This includes other lifts, including scissor lifts.

The proper training is essential for making sure operators and workers involved with cribbing construction and aerial lifts are prepared to recognize and avoid hazards. Aerial lift training can teach operators how to perform tasks on and off cribbing safely, and how to determine if a lift or work situation is safe or not.

The “Do’s” and “Don’ts” when Using Cribbing to Bolster your Aerial Lift

  • – DO consult with your lift’s operation manual in regards to the cribbing. Temporary cribbing should follow your manual’s guidelines.
  • – DO ensure that your cribbing structure is sturdy and stable. Most cribbing accidents are caused by faulty construction techniques. Again, your manual should have valuable input in regards to the proper way to use cribbing with your lift.
  • – DO select wood for construction cribbing that is solid, straight, and free of flaws to create the sturdiest foundation.
  • – DO make sure the wood cribbing construction structure is properly stacked to spread the load well and distribute the weight of the object.
  • – DON’T ignore the weather. Rain, mud, ice and other elements can and will impact your lift’s ability to maneuver on cribbing.
  • – DON’T structure the cribbing construction on surfaces that are painted or finished, since it can cause the cribbing to be slippery, especially when wet.
  • – DON’T stack the cribbing height more than three times the width.
  • – DON’T forget safety harnesses. You shouldn’t ignore them under normal operating circumstances, but double-check all safeguards are in place for aerial lift operators working with construction cribbing support.

Cribbing Construction and Aerial Lift Safety

Whenever an employee works with aerial lifts or scissor lifts, there are risks involved. This applies to construction cribbing. An improperly structured wood cribbing construction unit can cause the lift to become unstable and tip-over, potentially killing the operator on the lift and crushing workers nearby.

According to OSHA, it’s up to employers to ensure workers have received the comprehensive training they need to operate the controls of the aerial lift, perform equipment inspections, assess the environment, and perform tasks without danger, like cribbing.  Aerial lift certification training should teach workers involved with construction cribbing, the safest ways to work with cribbing on an aerial lift or scissor lift, and how to keep the structure sturdy, the lift balanced, and workers out of danger.

Where to Get Aerial Lift Safety Training for Cribbing Construction Workers

Proper construction cribbing falls right in line with proper aerial lift safety. And for the best aerial work platform safety training, only one provider gives you OSHA-compliant instruction, flexible course scheduling, and affordable value: Aerial Lift Certification. With the most up-to-date content available anywhere, our training sessions ensure your workforce is compliant with local and federal aerial lift regulations.

In only about one hour from any device with an internet connection, workers can complete the aerial lift and scissor lift training and print their operator card to begin work on construction sites and other work environments. The online course from ALC teaches operators everything they need to know to operate aerial work platforms safely and perform tasks like wood cribbing construction while staying safe and preventing accidents.

Whether you need a safety plan upgrade or want to reboot your existing aerial lift system, ALC has the tools and resources to ensure you’re OSHA compliant. Plus, the peace of mind knowing your aerial lift workers are properly trained to operate lifts and work with cribbing construction properly is hard to put a price tag on.

Skip the travel to an offsite facility for top quality training, and train your workers in-house with the top notch, OSHA-compliant courses from For more information about ALC, visit our contact page or call our aerial lift safety consultants at (888) 278-8896.

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