Installing corten steel edging involves digging a trench half the edging height deep, setting the steel with one-third to half buried, and securing it with ground pegs for a stable, straight line.
For the full breakdown, see our best Corten Steel Edging guide.
Getting a perfectly straight line with corten steel edging comes down to careful trenching and proper staking. How to install corten steel edging the right way starts with planning your layout and digging a trench half the height of the edging deep. This guide covers the key steps to get it right the first time.
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Plan Your Layout and Set the String Line
Start by laying out a taut bricklayer’s string line to mark the edging path. Secure it with corner clamps and trace the line with chalk. Check that corners are square using the 3-4-5 triangle method—a right triangle with sides measuring 3, 4, and 5 feet confirms a 90-degree angle. Refer to AHL Corten’s installation guide for more on this technique. Standard edging comes in 1.5 m or 2.4 m lengths with a typical thickness of 3 mm, which works for most standard curves. Tighter curves require bending the steel in 2-3 cm increments.
Dig a Clean, Level Trench
Dig a narrow trench to the calculated depth, removing any weeds and leveling the ground. The ideal depth is (frame width / 2) + 1 inch, or one-third to half the edging height. Trench walls must be vertical, and the bottom flat, level, and compacted. Leave about 1 inch of loose soil or sand at the bottom for fine-tuning the height. Minimum burial depth is 5 cm to hide self-tapping screws; for edging 390 mm and taller, bury at least 100 mm.
Set and Secure the Edging Strips
Attach ground pins and coupling plates with self-tapping screws, pre-drilling with an 8 mm drill bit. Dry-fit the first strip, aligning its ends with the string line within ±0.1 inches. Backfill a small amount of soil at the base to secure the first strip, then rake the substrate close and pack it hard. Use sand along the front edge to allow oxygen and water access for proper rust formation. For curves, insert stakes into end sleeves first to pivot the steel, then bend it in 2-3 cm increments using a plank placed perpendicular to the top. Common mistakes include rushing the first section, ignoring vertical trench walls, over-bending (correct by flexing opposite direction), and leaving visible screws (ensure 5 cm depth).
| Spec | Detail |
|---|---|
| Trench Depth | Half the edging height, or (frame width / 2) + 1 inch; bury one-third to half the total height |
| Minimum Burial Height | 5 cm for heights up to 390 mm; 100 mm for 390 mm and 590 mm edging |
| Ground Pegs | 4 for first strip, 3 for each additional strip |
| Drill Bits | 8 mm for ground pins and coupling plates; 5 mm for rivet guide holes above ground |
| Standard Lengths | 1.5 m or 2.4 m (metric; US users convert to feet) |
| Thickness | 3 mm typical for standard curves; tighter curves need bending in 2-3 cm increments |
| Soil Condition | Firm, slightly moist soil works best; front edge needs sand fill for oxygen/water access |
FAQs
How deep should the trench be for corten steel edging?
The trench should be dug to a depth of half the edging height, or enough to bury one-third to half of the total height. A minimum depth of 5 cm is required to hide self-tapping screws. For taller edging (390 mm or more), bury at least 100 mm.
How many ground pegs are needed per strip?
Use four fold-over ground pegs for the first edging strip to ensure stability. For each additional strip in the run, three pegs are sufficient.
Can corten steel edging be installed on curves?
Yes. Standard 3 mm thick edging can handle gradual curves. For tighter curves, bend the steel in small increments of 2-3 cm using a plank placed perpendicular to the top. Insert stakes into the end sleeves first to help pivot the steel as you shape it.
References & Sources
- AHL Corten. “How to Install Corten Steel Edging Perfectly Straight” Covers layout, string line, and 3-4-5 method for square corners.