concrete block screws
Drive fast, hold strong.
Simple to use, tough to loosen.
Designed for concrete block base
Product description
On concrete, brick, and block surfaces, Sinsun Concrete Block Screws hold things securely and safely. These screws have a special thread design and are made of case-hardened steel, which makes them very difficult to pull out and means you don't need wall plugs or anchors.With these tools, contractors and builders can achieve consistent results with masonry materials quickly and easily.
Sinsun's benefits
When you choose Sinsun, you're working with a manufacturer that cares about accuracy and long-lasting products. Our concrete screws are rigorously tested for strength and rust resistance to ensure they meet high industrial standards. We have a wide range of sizes and finishes to meet the needs of different projects. Our reliable supply chain and responsive customer support will help keep your business running smoothly.
What is a concrete block screw?
Concrete block screws are masonry anchors that can tap itself. It is made to work with hollow brick masonry units (CMU), which are also known as cinder blocks or breeze blocks. Block screws are different from regular masonry screws, which are not meant for solid concrete. They only need to grip the face shell, which is usually ¾" to 1" thick, without breaking it.
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Extra-deep threads
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Threads are extra-deep, so they grip the thin shell material better and are harder to pull out.
Knurled shank
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A rough part just above the threads that grips the block and keeps the screw from spinning if the hole is too deep (which happens a lot in blocks where breakouts can happen).
Sharp tip
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Sharp, aggressive points cut into the block cleanly, lowering the chance of cracking the face.
Partial thread design
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Only the part that connects to the block has threads. The smooth upper shank passes through fixtures without sticking.
Hardened steel
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Steel that has been hardened to cut through abrasive blocks but is also flexible enough to handle installation torque without breaking.
With tested
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The result is a screw that holds securely in CMU, with tested pull-out values of 450+ lbs for 1/4" diameter and up to 1,200+ lbs for 1/2" heavy-duty versions.
| Parameter | Details / Range | Notes |
| Diameter Options | 3/16" (4.8mm), 1/4" (6.35mm), 6.3mm, 7.5mm, 8mm | Metric and imperial sizes available |
| Length Range | 42mm to 300mm | Custom lengths may be available |
| Thread Design | High-low thread design, serrated V-threads, diamond-cut notches | Optimizes insertion and holding power |
| Head Types | Hex washer head, flat countersunk, pan head, cylindrical head | Various options for different applications |
| Drive Type | TX30 (Torx), Hex, Phillips #2/#3 | Torx drive minimizes cam-out |
| Drill Bit Size | 5/32" (4mm) for 3/16" screws, 3/16" (4.8mm) for 1/4" screws, 6mm for 7.5mm screws | Critical for prop |
| Base Material | 10B21 Carbon Steel | 304 (A2) or 316 (A4) Stainless |
| Hardness | HRC 45-50 (case-hardened) | HRC 48-52 (through-hardened) |
| Tensile Strength | 8.8 grade (800 MPa) | 10.9 grade (1,000 MPa) |
| Standard Coating | Blue Ruspert (720h) / Zinc (72h) | No coating required |
| Optional Coating | Hot-dip Galvanized (480h) | Passivated finish |
| Black Finish | Black organic (200h) | Not available |
| Diameter | Length | Thread Length | Head Style | Drive Type | Drill Bit Size | Min. Embedment | Pull-Out Load (8" CMU) |
| 1/4" | 2-1/4" | 1" | Hex / Flat | T-30 / #3 / 5/16" hex | 3/16" | 1" | 450 lbs |
| 1/4" | 2-3/4" | 1" | Hex / Flat | T-30 / #3 / 5/16" hex | 3/16" | 1" | 450 lbs |
| 1/4" | 3" | 1" | Hex / Flat | T-30 / #3 / 5/16" hex | 3/16" | 1" | 450 lbs |
| 1/4" | 3-1/2" | 1" | Hex / Flat | T-30 / #3 / 5/16" hex | 3/16" | 1" | 450 lbs |
| 1/4" | 4" | 1" | Hex / Flat | T-30 / #3 / 5/16" hex | 3/16" | 1" | 450 lbs |
| 5/16" | 3" | 1-1/4" | Hex | T-30 / 5/16" hex | 1/4" | 1-1/4" | 600 lbs |
| 5/16" | 3-1/2" | 1-1/4" | Hex | T-30 / 5/16" hex | 1/4" | 1-1/4" | 600 lbs |
| 5/16" | 4" | 1-1/4" | Hex | T-30 / 5/16" hex | 1/4" | 1-1/4" | 600 lbs |
| 5/16" | 5" | 1-1/4" | Hex | T-30 / 5/16" hex | 1/4" | 1-1/4" | 600 lbs |
| 3/8" | 3" | 1-1/2" | Hex | T-40 / 5/16" hex | 5/16" | 1-1/2" | 800 lbs |
| 3/8" | 3-1/2" | 1-1/2" | Hex | T-40 / 5/16" hex | 5/16" | 1-1/2" | 800 lbs |
| 3/8" | 4" | 1-1/2" | Hex | T-40 / 5/16" hex | 5/16" | 1-1/2" | 800 lbs |
| 3/8" | 5" | 1-1/2" | Hex | T-40 / 5/16" hex | 5/16" | 1-1/2" | 800 lbs |
| 3/8" | 6" | 1-1/2" | Hex | T-40 / 5/16" hex | 5/16" | 1-1/2" | 800 lbs |
Applications: Where & Concrete Block Screws
1. Attaching wooden plates (sole plates) to wooden floors
Concrete block screws are often used in framing and building to hold wooden sole plates (the bottom plate of a wall) to masonry slabs or block walls. This provides a stable base for both walls that can carry weight and walls that cannot.
Common uses include finishing a basement, framing walls inside, and building modular homes.
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2. Putting up heavy-duty brackets and shelves
These screws are ideally suited for attaching heavy-duty steel brackets, shelving units, and racking systems directly to concrete block walls in warehouses, garages, or factories.
Common uses include organizing a garage, storing things in a warehouse, setting up retail displays, and pallet racking in an industrial setting.
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3. Fixing Facades and Curtain Wall Systems
Curtain wall supports, cladding brackets, and exterior facade components are attached to an underlying concrete block structure with concrete screws.Their high shear strength ensures stability against wind loads.
Common Application: High-rise building facades, exterior insulation and finishing systems (EIFS), and metal cladding installation.
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4. Installing Electrical conduits and Mechanical Supports
These screws are used to attach electrical conduit clips, cable tray support clips, pipe hangers, and HVAC duct straps to concrete block walls and ceilings in MEP (Mechanical, Electrical, and Plumbing) installations.
Common Applications: Data centers, tunnel wiring, industrial plants, and commercial electrical rough-ins.
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| Parameter | Specification | Critical for |
| Hole Depth | Minimum 1/4" deeper than embedment | Proper thread engagement |
| Minimum Base Thickness | 1.5x embedment depth | Structural integrity |
| Edge Distance | 5x anchor diameter (minimum) | Preventing blow-out |
| Spacing Between Anchors | 10x anchor diameter (minimum), 16x for dynamic loads | Load distribution |
| Installation Tool | Hammer drill (drilling mode) + driver (rotation only) | Prevents over-torquing |
Real Customer Feedback
"For a historic building renovation, we needed to anchor new handrails into old, dense block. Sinsun 3/8" HD screws held perfectly—even after 100 years, the block didn't crack. The knurled shank kept the screw from spinning in the slightly oversized holes we had to drill."
"We use Sinsun concrete block screws on all our low‑income housing projects. They are fast to install, and the price is right. The 5/16" size is our go‑for shelving and kitchen cabinets. No complaints from our crews."
"Our data centre uses block walls for server room partitions. We tested Sinsun 1/4" screws against a leading brand—Sinsun had 20% higher pull‑out in our in‑house tests. Now we specify them for all cable tray and rack mounting."
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Q: What is the difference between concrete block screws and standard concrete screws?
A: Concrete block screws have deeper threads to engage the thin face shell of block, plus a knurled anti‑spin shank. Standard concrete screws are designed for solid concrete and may spin or strip in hollow block.
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Q: What drill bit size do I need for 1/4" block screws?
A: Use a 3/16" carbide‑tipped masonry bit.
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Q: How deep should I drill?
A: Drill through the face shell (typically 3/4" to 1" thick) plus an extra 1/4" for dust. Do not drill deep into the hollow core unless necessary.
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Q: Do I need to clean the hole?
A: Absolutely. Dust reduces holding power by up to 50%. Use compressed air or a vacuum.
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Q: Can I install these screws into mortar joints?
A: It's best to avoid mortar—it is weaker than block. If you must, use a slightly larger screw or test load capacity.
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Q: Are Sinsun concrete block screws removable?
A: Yes, they can be unscrewed and reused. The threads remain intact if not damaged during installation.
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Q: What pull‑out strength can I expect in CMU?
A: For 1/4" screws, 450+ lbs; for 3/8" HD, 950+ lbs; for 1/2" HD, 1,200+ lbs (ultimate loads). Apply a 4:1 safety factor for design.
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Q: Do you offer stainless steel versions?
A: Yes, 304 and 316 stainless are available by special order. Lead times apply.
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Q: Can I get samples?
A: Yes. Contact sales@sinsunfasteners.com or visit our website. We'll send up to 5 sizes for testing.
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Q: What is the minimum order quantity?
A: Stock sizes: 100 pieces. Custom production: 5,000 pieces.
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