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Digging a small underground firepit for safer cleaner fires!

Published: March 28, 2026

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Executive Summary

This video demonstrates digging and constructing a small underground firepit to create safer, cleaner contained fires. The build includes selecting a location, excavating to depth, installing a base layer (fabric, sand, gravel), and lining the pit with a metal ring or firebricks before testing a small burn.

Build Sequence

1. Site selection and safety check

Choose a level, open location away from structures, trees, and utilities. Check local regulations and call 811 if needed to locate underground utilities. Clear vegetation and combustible material from the immediate area.

15mbeginner

2. Mark pit diameter and depth

Mark the intended circular outline to match the fire ring or brick layout (typically 2–4 feet diameter). Decide on depth (commonly 12–24 inches) and mark center and perimeter with spray paint or stakes and string.

10mbeginner

3. Excavate soil

Dig out the marked area using a shovel, posthole digger, or pickaxe. Remove soil in manageable layers, keeping the sides fairly vertical and the bottom level. Wheelbarrow removed soil away from the site to use for backfill or disposal.

120mintermediate

4. Prepare base and drainage

Lay landscape fabric in the pit to suppress weeds and separate soil from aggregate. Add a 2–4 inch layer of sand to level, then add 2–3 inches of crushed gravel for drainage and stability. Tamp each layer to compact.

30mintermediate

5. Dry-fit and install ring/bricks

Place the steel ring or arrange firebricks around the perimeter on the prepared base. Check level and adjust with sand/gravel as needed. If using bricks, stagger joints for strength and leave ventilation gaps as desired.

30mintermediate

6. Finish interior and backfill

Add a thin layer of sand or small gravel inside the ring for final leveling. Backfill and pack soil around the outside edge to secure the ring/bricks and create a smooth transition to surrounding ground. Clean up debris.

20mbeginner

7. Test fire and safety check

Build a small test fire to check airflow and containment. Keep water, a fire extinguisher, or bucket of sand nearby. Observe for excessive smoke or heat transfer to surrounding soil or vegetation and make adjustments as necessary.

30mbeginner

Frequently Asked Questions

How deep should the pit be?

A common depth is 12–24 inches depending on desired containment and frost depth in your area. Too shallow reduces containment and too deep can create drainage or airflow issues—12–18 inches is typical for a small backyard pit.

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How do I safely extinguish the fire?

Let the fire burn down, spread out the coals with a shovel, and douse with water or cover with sand until completely cool. Never leave a smoldering fire unattended and always ensure embers are fully out before leaving the site.

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Can I use regular bricks or pavers for the lining?

Use fire-rated bricks (firebricks) where direct flames and high heat will contact material. Regular landscaping bricks or pavers can crack or spall under high heat and are not recommended for the area directly exposed to flames.

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Parts Used (6)

Steel fire pit ring
$50

Prefabricated ring to protect soil and provide a finished edge.

Fire bricks (set, approx. 6–10)
$60

Use fire-rated bricks for lining the inside where flames contact masonry.

Crushed gravel (½ yard or bagged equivalent)
$25

Provides drainage and a stable base under the pit.

Play sand / coarse sand (1–2 bags)
$5

Thin layer above fabric to help level and insulate.

Landscape fabric
$10

Prevents weed growth and keeps gravel/sand separated from soil.

Grate / cooking grate (optional)
$25

Optional metal grate for cooking or improved airflow.