Cribbing Construction 101
Cribbing (also called a “box crib”) is a popular practice among aerial lift operators, construction foreman, and other job site workers, and it is used in a variety of work situations. Cribbing construction techniques can be both incredibly effective and incredibly dangerous if the necessary safety precautions aren’t taken.
What is Cribbing in Construction?
Just what is cribbing in construction? The term refers to the temporary work structures you often see used to support heavy objects during the construction process. Cribbing involves the building of temporary wooden structures to support heavy machinery. Without proper cribbing techniques employed, the process can be dangerous to workers. Of course, crib walls have been around for more than 40 years, and best practices have evolved significantly over time. With the right training and the right aerial lift, wood cribbing can be entirely safe to construct.
How Cribbing Construction Works
The use of cribbing construction is essential for many extrication operations. Its most common use is to stabilize large objects and heavy equipment.
Stability is important with any type of cribbing material. Cribbing should also be free from paint or finishes. Pieces of wood that are 2×2 and 4×4 are common for use with cribbing construction work.
The actual work of cribbing involves multiple pieces of wood that are laid on their 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 in.
- The weight limit for a 44 cribbing structure is about 24,000 lbs., and for a 6’×6′ structure, it’s about 60,000 lbs.
Wood cribbing blocks used at each level increase the number of support points. That way, they improve a crib tower’s overall strength and stability.
Cribbing Construction Materials
Wood is the preferred cribbing construction material, but plastic is also popular. Wood cribbing blocks often consist of softwoods like Douglas Fir or Southern Pine. To determine the strength of wood cribbing blocks, it is important to evaluate several factors, including the wood species, moisture content, length, and thickness.
Plastic and steel may be used for cribbing due to the fact that they are sturdier and less susceptible to chemical corrosion than wood. But for most purposes, wood works well for cribbing.
Concrete is another sturdy, practical material for crib walls. It can hold a heavier load, which makes the crib walls more secure. However, there is less flexibility than with wood, which has more give with a heavy load. Concrete doesn’t rot or deteriorate, which makes it ideal for long-term projects. It won’t absorb water, which can be detrimental to a crib wall that must support heavy equipment.
Jobs in the Cribbing Construction Industry
People who do cribbing are known as cribbers. They work with wood and concrete to build crib walls as foundations for buildings and as a temporary construction structure.
Cribbing construction crews and other workers on job sites. They must stay up to date on the latest safety requirements and follow OSHA guidelines. They may begin their career as an apprentice under a journeyman until they have learned the trade at which point they become journeymen.
According to OSHA, it’s up to employers to ensure workers have received the training they need to:
- Operate the controls of an aerial lift
- Inspect equipment
- Assess a work environment
- Perform cribbing and other tasks safely
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. It should also teach these workers how to keep a structure sturdy and balanced and eliminate dangers.
Cribbing Construction Safety Risks
Stable, flexible woods should be used for cribbing. These woods can support heavy weights; plus, they are more prone than other woods to creak or make other noises if too much weight is present.
If cribbing makes noise, it should be replaced immediately. The longer the noise is present, the more likely it becomes that the cribbing is defective. If you do not address the issue, the cribbing could shatter, which could break your equipment or harm your workers. Brittle woods are susceptible to splitting or snapping under heavy weight. As such, these woods should always be avoided for cribbing.
For aerial lift operators, cribbing construction has to be undertaken with extra caution. Given the top-heavy loads and height of some aerial lifts, wood cribbing should only be done under professional, certified supervision. This includes cribbing with scissor lifts and common aerial work platforms.
Proper training is essential to ensure operators and workers involved with cribbing construction and aerial lifts are prepared to recognize and avoid hazards. Aerial lift training teaches operators how to safely perform tasks on and off cribbing.
Cribbing Construction Best Practices
There’s no denying the risks involved with wood cribbing. By understanding the potential for accidents, employees can guard against the very worst workplace hazards. Always be sure to consult your lift’s operation manual to see what it says about cribbing construction before beginning this kind of work. Select materials that are straight, solid, and free of obvious flaws. Design a cribbing stabilization plan and implement it with fidelity. Be sure to factor in the work surface below – unstable ground can impact the safety of your cribbing. Always wear the necessary PPE like glasses, a helmet, and a reflective vest, as well as a safety harness.
As you begin a cribbing construction project, be sure not to ignore the weather. Mud, rain, ice, and snow can impact your lift’s ability to maneuver. Don’t structure cribbing on surfaces that have been painted or finished. Never stack cribbing more than three times its width. It’s also a bad idea to pull all cribbing out from beneath a supported load at once. While there are risks involved with this kind of work, a little foresight can go a long way in preventing accidents.
Sign Up for Aerial Lift Certification Training with ALC
Proper cribbing construction falls right in line with proper aerial lift safety. For the best aerial work platform safety training, only one provider gives you OSHA-compliant instruction, flexible course scheduling, and affordable pricing — AerialLiftCertification.com. You can get workers certified with the Aerial Lift Operator Training Kit for $299, Train a Trainer course for $149, or the bundle at $399. Workers can learn through guided training, with self-paced learning, or through group training. To find out more about our aerial lift certification or to sign up for our training program, please contact us online or call us today at (888) 278-8896.