The right concrete anchor is the difference between a secure installation and a structural failure. Whether you’re bolting structural steel to a slab or suspending ductwork from an overhead deck, your anchor needs to match the load, base material, and on-site conditions. Concrete anchors fall into two main categories: mechanical and chemical. Mechanical anchors grip through expansion or wedging action, while chemical anchors bond through adhesive. Each type has specific applications where it performs best. This guide walks you through the common types of concrete anchors, so you can match the right anchor to the job the first time.
What Are Concrete Anchors?
Concrete anchors are fasteners that attach objects to concrete, masonry, and brick. Unlike standard concrete screws or bolts and washers that thread into wood or metal, concrete anchor bolts work differently. They expand against the base material, wedge into a drilled hole, or bond through adhesive. That mechanism is what gives them holding strength in hard, dense substrates. Concrete anchors are engineered to perform reliably under conditions where traditional fasteners would fail. Common substrates include:
- Solid concrete block, such as poured slabs, footings, and walls
- Masonry, like concrete masonry unit (CMU) block or brick
- Hollow block or core-filled materials
Choosing the wrong type of anchor for your substrate is one of the most common installation mistakes, and one of the most avoidable.
Mechanical vs. Chemical Anchors: Understanding the Difference
Before selecting a specific anchor, you need to understand how each type works and where it fits:
- Mechanical anchors: These use physical expansion or wedging action to lock into the base material. They install faster, require no cure time, and work well for most general construction applications.
- Chemical anchors: These use an adhesive system, typically epoxy or acrylic, that’s injected into a drilled hole around a threaded rod or rebar. The adhesive cures and forms a bond across the full embedment depth, which is why chemical anchors handle higher loads, tighter edge distances, and cracked concrete better than most mechanical options.
| Feature |
Mechanical Anchors |
Chemical Anchors |
| Installation speed |
Fast: drill, insert, torque |
Slower: requires cure time |
| Load transfer |
Mechanical expansion/wedge |
Full-depth adhesive bond |
| Cure Time |
None—immediate load |
Minutes to hours |
| Best substrate |
Solid concrete, masonry |
Cracked concrete, close edges |
| Removable |
Some types, yes |
Generally no |
Generally, use mechanical anchors for standard installations where speed matters and load requirements are moderate. Conversely, use chemical anchors when the application is engineered, load demands are high, or base material conditions are challenging.
Types of Mechanical Concrete Anchors
Mechanical anchors cover a wide range of applications, from heavy structural connections to light-duty fixture mounting.
Wedge Anchors
Wedge anchors are the go-to choice for heavy-duty fastening in solid concrete. As the nut is tightened, the wedge clip at the base of the anchor expands outward, creating a mechanical lock against the hole wall. That wedging action generates substantial pullout and shear resistance. Common applications include:
- Structural steel connections
- Handrails and guardrails
- HVAC equipment bases
- Machinery anchoring and industrial mounting
Fasteners Etc., Inc. stocks wedge anchors in galvanized or zinc-plated carbon steel and stainless-steel options for increased corrosion resistance.
Sleeve Anchors
Sleeve anchors expand over a wider surface area than wedge anchors, which makes them more versatile across different substrates, including solid concrete, hollow block, drywall, and brick. As the bolt is tightened, the sleeve expands uniformly and compresses against the hole walls, distributing loads across a large diameter. They offer good shear performance and are available in multiple head styles. This makes them practical for applications where aesthetics or flush finishes matter.
Drop-in Anchors
Drop-in anchors are internally threaded expansion anchors designed for flush-mount installation. The anchors sit flush with the concrete surface after setting, which makes them ideal for applications where a clean, finished look is required. They’re commonly used for threaded rod attachments, suspended systems, and rod hanger connections. Fasteners Etc., Inc. offers Simpson Strong-Tie drop-in anchors, which require fewer hammer drives for faster installation in pre-drilled holes.
Setting tools are also available to ensure proper anchor expansion and code-compliant installation.
Pin Drive and Light-Duty Anchors
Pin drive anchors are designed for quick installation under static loads. The pin is driven through the anchor with a standard hammer, expanding the body into the base material. Once set, the design provides tamper resistance, which makes it practical for public-facing installations. These anchors work well for light- to medium-duty applications in concrete, brick, block, and stone, including:
- Electrical conduit supports
- Signage
- Light fixture mounting
They won’t replace a wedge anchor for structural loads, but for high-volume, repetitive light-duty installs, they’re a fast and reliable option.
Chemical Anchor Systems: When and How to Use Them
Chemical anchors use a two-component adhesive injected through a mixing nozzle into a drilled, cleaned hole. A threaded rod or rebar is inserted into the wet adhesive, which cures around the insert and bonds it to the full depth of the hole. That full-depth bond is what makes chemical anchors capable of handling loads that mechanical anchors can’t. Chemical anchors are the right choice when:
- High-strength or engineered connections are required.
- The base material is cracked concrete.
- Edge distance or spacing constraints don’t allow for mechanical expansion.
- The application is water-saturated or submerged.
- Rebar doweling or post-installed anchors are part of an engineered system.
Fasteners Etc., Inc. carries the Simpson Strong-Tie
adhesive anchoring line.
How to Choose the Right Concrete Anchor
Selecting the right anchor comes down to matching the product to your specific job conditions. A few key factors should guide your decision:
- Base material: Solid concrete, hollow block, brick, and stone each respond differently to mechanical expansion. Confirm your substrate before specifying an anchor.
- Load requirement: Light-duty fixture mounting calls for a different anchor than a structural steel connection. Know your load values, shear, and tension.
- Installation conditions: Consider edge distance, embedment depth, moisture exposure, and whether the connection needs to be removed in the future.
- Hardware type: Some anchors accept threaded rod, and others require specific threaded bolt sizes. Match your anchor to the hardware you’re working with.
- Application type: Common applications include structural steel and handrails, HVAC equipment and duct supports, equipment mounting and racking, and suspended systems with rod hangers.
If you’re working from engineered drawings, the anchor specification is usually provided. If you’re selecting on your own, start with the load capacity and base material. Those two factors will narrow your options quickly.
How to Properly Install Concrete Anchors
Even the right fastening system will fail if it’s not installed correctly. Most anchor types require pre-drilling a hole, and the drill bit size and embedment depth must match manufacturer specifications, not your best estimate. Follow these rules:
- Use the correct carbide-tipped masonry bit diameter specified for the anchor to ensure a proper hole diameter.
- Drill to the required embedment depth.
- Clean the hole of dust and debris, especially for chemical anchors, where a clean bore is critical to adhesion.
- Use a proper setting tool for anchors, like drop-ins that require controlled expansion.
- Follow published load ratings and don’t exceed them.
At Fasteners Etc., Inc., we carry drill bits and setting tools to make sure the installation is done right.
Fasteners Etc., Inc. Has the Right Anchoring Solution for the Job
Whether you need a single wedge anchor or a full chemical anchoring system for an engineered application, Fasteners Etc., Inc. has the inventory and the expertise to support it. Our team is available to help you select the right concrete fastener based on your load requirements, base material, and installation conditions, so you don’t have to guess. We offer fast shipping nationwide on all orders, with volume discounts available for larger products. Browse our
anchoring page to explore product options or
contact us today for technical guidance and
custom quotes.
