Choosing the Right Jacking Timbers for Heavy Rigging
Jacking timbers—also known as cribbing timbers or blocking—are a critical component of jack-and-slide and heavy lifting operations. Once a lifting or skidding method is selected, choosing the right timber material becomes one of the most important performance and safety decisions in the system.
Jacking timbers provide the stable, load-bearing foundation required to safely support massive structures during lifting, skidding, alignment, and installation. In heavy rigging applications, timbers must deliver exceptional compressive strength, crush resistance, dimensional stability, and durability. They must also withstand fire exposure, moisture, rot, and pests—while remaining manageable for rigging crews to transport and stack on active job sites.
For engineered heavy lifts, material choice directly affects load control, repeatability, and long-term reliability in the field.
What Are Jacking Timbers?
In technical terms, jacking timbers are high-strength blocking materials used to support loads from below during hydraulic lifting, skidding, and alignment operations.
In practical terms, they are what allow crews to safely build, adjust, and maintain support beneath a load as it moves.
Jacking timbers are stacked in controlled configurations to distribute load evenly, maintain stability, and provide predictable support throughout an operation. Their performance characteristics directly influence how confidently a load can be lifted, held, or repositioned.
Why Material Selection Matters in Heavy Rigging
Not all timbers perform the same under extreme loads.
In heavy rigging environments, jacking timbers must reliably handle:
- Very high compressive forces
- Repeated loading and unloading cycles
- Uneven site conditions and long-duration support
- Environmental exposure over the life of a project
Small variations in material density, moisture content, or dimensional consistency can translate into uneven load distribution or reduced predictability. For this reason, timber selection is not simply a matter of availability—it is an engineering decision tied directly to safety margins and performance.
Common Jacking Timber Materials Used in Practice
Two primary material categories are commonly used in modern heavy rigging applications:
- Traditional tropical hardwoods, such as Ekki (Azobé / Red Ironwood)
- Engineered composite materials, including bamboo-based Engineered Bamboo Composites (EBCs)
Each category offers distinct advantages and tradeoffs depending on project requirements, environmental conditions, and sustainability considerations.
Ekki Jacking Timbers (Traditional Hardwood Option)
Ekki—also known as Azobé or Red Ironwood—is a tropical hardwood sourced from West African forests. It has been used in heavy rigging and lifting applications for decades and remains a long-standing industry benchmark.
Ekki is known for:
- Extremely high compressive and bending strength
- Natural resistance to fire, rot, moisture, and insects
- Proven long-term performance in demanding lifting environments
Standard Ekki jacking timbers are commonly produced in sizes such as 4″ × 4″ × 40″ and weigh approximately 26 lb per timber, with larger cross-sections and custom lengths available for specialized applications.
Sustainability Considerations for Ekki
Ekki is a slow-growing tropical hardwood. As global demand has increased, newly harvested material often comes from younger trees, which can exhibit lower density and greater susceptibility to twisting and cracking compared to older-growth timber. This has raised legitimate concerns around long-term supply consistency and sustainability.
Why Not Use Common Hardwoods?
A common question is whether widely available hardwoods such as white oak can replace Ekki in heavy lifting operations.
While oak can be used in certain field applications, Ekki is approximately three times stronger than white oak in both bending and crushing tests. Achieving comparable load capacity with oak often requires significantly larger cross-sections—commonly 8″ × 8″ timbers weighing 80–100 lb—and may still fall short for critical heavy-lift scenarios.
Engineered Bamboo Composite Jacking Timbers (Dragonwood)
Engineered Bamboo Composite (EBC) timbers were developed to address many of the consistency, supply, and sustainability limitations associated with traditional hardwoods.
Dragonwood is an EBC specifically engineered for industrial jacking and blocking applications. It is composed of approximately 80% bamboo fibers and 20% resin, resulting in a highly uniform and dimensionally stable material.
Key performance characteristics include:
- Strength and durability comparable to Ekki
- High resistance to fire, moisture, rot, and insects
- Virtually no warping, shrinking, or cracking
- Exceptional dimensional consistency across timbers
Standard Dragonwood timbers are produced in sizes such as 4″ × 4″ × 40″ and weigh approximately 28 lb, with custom sizes and lengths available.
Sustainability Advantages of Engineered Bamboo
Bamboo is one of the most sustainable construction materials available. It grows rapidly, regenerates without replanting, thrives in diverse climates, and actively sequesters carbon dioxide. These characteristics make engineered bamboo composites an environmentally responsible alternative to slow-growing tropical hardwoods.
Data-Driven Performance Testing
Reliable material selection depends on data—not assumptions.
Because published performance data on jacking timbers is limited, and because newer materials and younger-growth hardwoods may not perform comparably to older study results, Hydra-Slide partnered with the University of Waterloo’s engineering department to conduct comprehensive mechanical testing on both Ekki and Dragonwood timbers.
Preliminary results demonstrate excellent load-bearing capability and mechanical performance for Dragonwood, validating its suitability as a high-strength alternative to traditional hardwood.
Comparing Jacking Timber Options
The table below highlights the practical tradeoffs engineers and rigging crews typically evaluate when selecting jacking timbers for heavy lifting and jack-and-slide operations.
How Engineers Typically Select Jacking Timbers
Selecting the right jacking timbers ultimately comes down to matching material performance to the specific demands of a project. Engineers and rigging teams typically evaluate:
- Load magnitude and required safety margins
- Need for dimensional consistency across blocking stacks
- Environmental exposure (moisture, fire risk, pests)
- Handling weight and crew ergonomics
- Sustainability requirements or material availability
- Repeatability across long or multi-phase projects
Get Expert Guidance on Jacking Timbers and Heavy Lifting Systems
Every project presents its own constraints related to load characteristics, site conditions, and operational requirements. Selecting the appropriate jacking timber material can significantly impact safety, performance, and long-term reliability.
Hydra-Slide engineers work directly with clients to help:
- Evaluate timber performance requirements
- Select the appropriate material for the application
- Integrate jacking timbers into complete lifting and skidding systems
