Fasteners
Bolts
Hillman
$5-$30 per packLag Bolts for Heavy-Duty Structural Connections
Lag bolts are large-diameter fasteners with a hex head and coarse wood-thread shank for heavy-duty timber connections. Driven with a wrench or socket, they provide exceptional clamping force for ledger boards, beam connections, and structural applications.
Key Features
- Hex head for high-torque wrench driving
- Coarse wood threads for deep holding power
- Galvanized and stainless options
- Diameters from 1/4in to 3/4in
- Lengths from 1in to 12in
Specifications
Material: Carbon steel
galvanized
or stainless | Head: Hex | Thread: Coarse wood | Diameters: 1/4in to 3/4in | Lengths: 1in to 12in
Best For
Ledger board attachment
Beam-to-post connections
Deck framing
Heavy timber construction
Compatible Materials
Dimensional lumber
Timber beams
Pressure-treated lumber
Glulam
LVL
Pros & Cons
Pros
- ✓ Extremely high clamping force
- ✓ Simple wrench installation
- ✓ Available in large sizes
- ✓ Code-approved for structural connections
Cons
- ✗ Require pre-drilling two hole sizes
- ✗ Slow to install vs structural screws
- ✗ Can crack wood if overtightened
Installation Tips
Pre-drill a pilot hole matching the root diameter and a clearance hole matching the shank through the top piece. Use a washer under the hex head to distribute load.
Frequently Asked Questions
Most codes require 1/2-inch diameter, spaced 16 inches on center in a staggered pattern.
Yes, always. Drill a pilot hole for the root diameter and a clearance hole through the first piece.