Are you trying to choose the right fastener for your construction or installation project? This guide explains the differences between Dynabolts and Anchor Bolts, including load capacity, installation, materials, use cases, and safety considerations. Use this information to select the best option for your needs.
What Is a Dynabolt?
A Dynabolt is a type of medium-duty expansion anchor, often used in masonry and concrete. It is composed of a bolt surrounded by a metal sleeve. When tightened, the sleeve expands to grip the hole walls, offering a strong and reliable hold for various applications.
Key Properties:
- Commonly made of zinc-plated steel or stainless steel
- Load capacity: 2,600 to 5,000 lbs (11.57–22.24 kN) pull-out strength (varies by size, depth, and substrate)
- Available in multiple diameters and lengths
- Designed for solid concrete, stone, and brick applications
- Limited use in hollow concrete unless specifically rated for that purpose
What Is an Anchor Bolt?
Anchor Bolts are heavy-duty fasteners embedded in concrete to secure structural elements. They come in multiple types: L-shaped, straight, headed, swedge, and hex head, each suited to specific structural needs.
Key Properties:
- Made from high-grade carbon steel or stainless steel
- Load capacity: typically over 5,000 lbs; can reach tens of thousands of pounds depending on size and installation
- Available in standard and custom-fabricated sizes
- Primarily used in new concrete pours but some types allow post-installation with epoxy
- Ideal for permanent structural anchoring
Materials and Resistance
| Feature | Dynabolt | Anchor Bolt |
|---|---|---|
| Common Materials | Zinc-plated steel, stainless steel | Carbon steel, stainless steel |
| Corrosion Resistance | Moderate to high (depends on coating) | High (with galvanized or stainless steel) |
| Chemical Resistance | Varies by material grade | Varies by grade and coating |
| UV & Moisture Exposure | Performs well with proper coatings | Suitable for outdoor conditions |
Note: Temperature resistance varies by alloy and finish. Always consult the product’s technical data sheet (TDS) or manufacturer specification.
Load Capacity and Performance
| Load Type | Dynabolt Range | Anchor Bolt Range |
|---|---|---|
| Tensile Strength | 2,600 – 5,000 lbs | 5,000+ lbs to 20,000+ lbs (varies widely) |
| Shear Strength | Depends on diameter and embedment | Higher for thicker bolts with deeper embedment |
| Safety Factors | Refer to engineering design specs | Application-specific, typically 2–4x working load |
For accurate selection, refer to building code load tables and manufacturer documentation.
Installation Requirements
Dynabolt Installation:
- Drill hole with hammer drill and masonry bit (match Dynabolt diameter)
- Clean out dust for proper expansion
- Insert Dynabolt and tighten bolt
- Typical installation depth: 40–90 mm depending on bolt size and load requirements
Anchor Bolt Installation:
- Usually installed before or during concrete pouring
- Position bolts with templates to maintain alignment
- Embed 100 mm to 500+ mm depending on design requirements
- Epoxy-set anchor bolts are installed post-pour and require adhesive cure time
Tools and Equipment
| Tool | Dynabolt | Anchor Bolt |
|---|---|---|
| Drill Type | Hammer drill | Core drill (post-installed) / N/A (cast-in) |
| Torque Wrench | Yes (required for torque specs) | Yes (especially for post-installed anchors) |
| Drill Bit Size | Matches anchor size | Depends on epoxy sleeve or hole requirements |
Common Installation Errors
- Drilling the wrong hole size (too wide or shallow)
- Skipping debris removal before insertion
- Over-torquing, causing damage or reduced holding power
- Installing in weak or cracked concrete without proper evaluation
Use Cases by Industry
| Application | Recommended Anchor Type |
|---|---|
| Light structural fixtures | Dynabolt |
| HVAC mounting | Dynabolt or Light-duty Anchor Bolt |
| Industrial machinery base | Anchor Bolt |
| Outdoor signage | Anchor Bolt (galvanized or stainless) |
| Concrete foundations | Anchor Bolt |
| Racking and shelving | Dynabolt (medium-duty) |
Substrate Compatibility
| Substrate | Dynabolt | Anchor Bolt |
|---|---|---|
| Solid Concrete | Yes | Yes |
| Hollow Concrete | Limited (check design) | Rarely suitable; may require specialty inserts |
| Brick | Yes (solid brick preferred) | Not recommended due to unpredictable hold |
| Masonry Blocks | Yes (with hollow-wall models) | Not preferred without reinforcement |
Cost Overview (Estimates Only)
| Type | Approximate Cost (USD per piece) |
|---|---|
| Dynabolt | $0.80 – $3.00 |
| Anchor Bolt | $2.00 – $12.00 |
Prices fluctuate based on region, supplier, size, finish, and quantity ordered. Confirm pricing before budgeting.
Compliance and Safety
| Feature | Dynabolt | Anchor Bolt |
|---|---|---|
| Building Code Compliant | Yes (if tested and rated) | Yes (required in structural systems) |
| Seismic Rated | Select models only | Common in seismic-grade systems |
| PPE Required | Gloves, goggles | Gloves, goggles, boots |
| Maintenance | Annual torque check | Inspect during structural reviews |
Engineering judgment and local codes must be followed. Safety factors depend on use-case and should not be arbitrarily chosen.
Troubleshooting Common Issues
Dynabolts
- Anchor spins in hole: Hole may be too wide or concrete compromised; try chemical adhesive or replace with larger anchor
- Bolt loosens after tightening: Confirm proper embedment depth, hole cleanliness, and torque specification
Anchor Bolts
- Anchor misaligned during pour: Secure bolts using positioning templates or jigs
- Anchor fails pull-out test: Increase embedment depth or switch to higher-grade anchor with chemical bonding
Alternative Fasteners
| Fastener Type | Use Case |
|---|---|
| Chemical Anchors | High-load or retrofit applications |
| Toggle Bolts | Hollow wall and ceiling fixtures |
| Sleeve Anchors | Versatile medium-duty solutions |
| Wedge Anchors | Solid concrete, medium/heavy duty |
Conclusion
Dynabolts are ideal for medium-duty anchoring in solid masonry and concrete, particularly when fast and convenient installation is important. They are suitable for most general construction uses where the substrate is solid and undamaged. Anchor Bolts, on the other hand, are designed for critical structural applications. They offer superior load capacity, longer embedment options, and are often required for compliance in permanent and seismic installations.
When selecting between Dynabolts and Anchor Bolts, always consult manufacturer data sheets, structural load tables, and local building codes. For load-bearing or safety-critical structures, a licensed engineer’s input is essential.
Still uncertain? Reach out to a structural engineer or qualified contractor before proceeding with installation.
Read More – How to Install Eye Bolts in Concrete
I wish to secure two hardwood uprights to concrete columns using something like dynabolts and then screw a metal privacy screen onto the timber uprights. The installation site is exposed to high winds so I need to guarantee that the fixings will hold. What are your recommendations for the timber fixings to the concrete wall
Dynabolts (also known as expansion bolts) are an excellent solution, for your task. You can also consider chemical anchor bolts for superior grip, sleeve anchors for reliable hold, or through-bolts, which are ideal for securing in wider spaces. 🫡