How to build a garden fire pit

Inspired by a helpful YouTube guide. This walk-through draws on the popular UK how-to video "How to Build a Fire Pit" from Wickes, the UK DIY and builders' merchant. Their guide covers the key stages concisely and is honest about the materials you actually need. Worth a watch before you head to the builder's merchant — the advice on fire-safe materials is particularly useful if you have not done this before.

1. Choose a safe location

Keep the fire pit at least 3 m from the house, garden buildings, fences, and overhanging trees. On a still evening 3 m feels like plenty; on a breezy one it can feel close. Err on the side of more space rather than less.

Avoid low-lying areas of the garden where smoke will pool and settle. A spot with a gentle prevailing breeze past it is ideal — it keeps the fire burning well and carries smoke away from where people are sitting. Check with your local council if you are unsure about restrictions on garden fires; most UK councils do not prohibit garden fires outright, but causing a nuisance to neighbours is a different matter.

2. Mark out the shape

A circle of 900 mm to 1.2 m internal diameter is a practical size for a domestic fire pit. Small enough to feel like a fire, large enough to actually burn logs properly. Use a cane in the centre with a piece of string tied to it — hold a can of line marker paint at the other end and walk a circle to mark the ground.

Mark the outer diameter too, allowing for the width of your chosen brickwork. Standard engineering bricks are 215 mm long; for a circular build you will use short sections of brick set on a slight angle, so plan to cut a good number. That said, circular fire pits are also commonly built with a regular polygon — eight or twelve sides looks circular from a few feet away and is far easier to lay.

3. Excavate and prepare the base

Dig out the circle to a depth of around 200 mm. The base needs to drain freely, so add a 100 mm layer of compacted hardcore or coarse gravel before any mortar goes down. This stops the base retaining water, which can cause the brickwork to crack badly as it heats up.

On top of the hardcore, lay a bed of dry-mixed sharp sand and cement (about 5:1 ratio, mixed dry) around 50 mm deep. Level it carefully with a float. You are not looking for a perfectly finished surface — just a flat, stable base for the first course of bricks.

4. Choose fire-safe materials

This step is where many people cut corners and regret it. Standard house bricks can crack and shatter explosively when they get hot — especially if they have absorbed moisture. You need either engineering bricks (which are dense and low-absorption), proper firebricks, or refractory concrete blocks. All are available from builders' merchants.

For the mortar, use a refractory or fire cement mortar, not standard ready-mix. It is slightly more expensive but stays put at the temperatures a fire pit reaches. Standard mortar will crack, crumble, and fall out of the joints within a few fires.

5. Build up the walls

Lay the first course of bricks in a circle on the prepared base. Use a spirit level across pairs of bricks to keep the course level as you go around. Bed each brick in a thin layer of fire-cement mortar — around 10 mm is right. Check each course is level before moving on to the next one.

Build to four or five courses high, which gives you an internal depth of around 250–300 mm. Offset the joints between courses as you would with standard brickwork. Keep checking that the circle is maintaining its shape as you build up — it is easy to drift slightly oval over several courses if you are not careful.

6. Point the mortar joints

Once all the courses are laid and the mortar has set firm (leave it 24 hours), go back and point any gaps or shallow joints. Use a pointing tool or the handle of an old brush to press the mortar firmly into the joint and finish it with a slightly recessed, bucket-handle profile. This keeps rain from sitting on horizontal surfaces and penetrating the joints.

Brush off any smears of mortar from the face of the bricks with a damp sponge while it is still fresh. Dried mortar smear on brick face is difficult to remove cleanly without acid washing.

7. Cure it before the first proper fire

New fire-cement mortar needs to be cured gradually. Light a small, gentle fire first — a handful of kindling only. Let it burn out and cool completely. Then a slightly larger fire. Then a proper fire on the third go. Jumping straight to a full-size blaze can cause the mortar to crack as it cures too fast and unevenly.

Keep a metal grate or fire basket inside the pit to lift the logs off the base slightly. It improves airflow and the fire burns more cleanly. A circular grate designed for fire pit use sits neatly and is worth the small outlay.

When to call a handyman

The brickwork is within range of a confident DIYer, but if you want a larger fire pit integrated with seating walls, raised planters, or a paved area around it, that is a more involved build. Richard can help with groundwork, outdoor paving, and garden structure projects in Sandwich and East Kent.