How to Break Stones for a Wall

Use a sledgehammer to shatter rocks only if size or shape is unimportant.

A dry-stacked or mortared stone wall can act as an attractive and practical border or accent or means to retain earth on a slope. There are several key aspects of stone wall construction that influence the appearance and stability of the completed wall. Proper stone selection and preparation is one of these factors. Round rocks are generally difficult to break reliably and are typically not desired for wall-building, so this method of breaking applies to fairly flat rocks. Irregular rocks can be broken by piecemeal chiseling, while flat, thin rocks like flagstone can be scored on both sides along the desired break line and then struck with a stone hammer to sever cleanly.

Things You'll Need

• Chalk or pencil
• Level, ruler or other straight edge
• Safety glasses
• Work gloves
• Stone hammer
• Blunt chisel
• Wooden block or timber
• Sledgehammer

Instructions

Breaking Irregular Stones

1. Chalk or pencil a line where the planned rock face will be, using a snapping chalk line, measuring tape or another straight-edged object as a guide.

2. Chisel off small portions of the undesired stone at a time. Place the tip of the blunt chisel against the stone no more than an inch or two away from the edge of the stone at about a 45-degree angle and strike it sharply with the stone hammer.

3. Chip off rock pieces in small amounts, working from the edge of the unwanted section of stone towards the chalk line until the desired shape is reached.

Breaking Thin, Flat Stones

1. Chalk or pencil a line on both sides of the stone where the break is desired.

2. Score both sides of the stone by lightly hitting the chisel with the hammer along the entire length of the line.

3. Prop the stone up on a wooden block or thick timber so that the scored line is in the air just past the block, with the section of the stone to be removed hanging over.

4. Strike the surface of the stone lightly near the scored line with the stone hammer until the stone breaks. If the stone does not break easily, deepen the scoring and increase the amount of force used with the hammer.

Tips & Warnings

• If simply breaking large rocks into smaller pieces that do not necessarily require a clean, even face, use a sledgehammer to split the rocks.

• When working with stone, wear adequate work gloves and use shatterproof safety glasses to protect your eyes from flying pieces of stone.

References

• The University of Connecticut/Stone Wall Initiative: Building Stone Walls - Construction
• Popular Mechanics magazine; Laying Flagstone; Max Alth
• Popular Mechanics magazine; Build a New England Stone Fence; Richard F. Dempewolff
• he Natural House; Daniel D. Chiras