Garden Fire Pit Buying Guide: Steel, Cast Iron and Corten Compared

A garden fire pit in the UK comes in three materials: powder-coated steel (cheapest, lightest, 5-10 year life with care), cast iron (heaviest, longest-lived, traditional look) and Corten weathering steel (premium patina, lifetime piece, no painting ever). The buying decision is mostly about wall thickness, weight and how the metal handles British rain. This guide covers the three materials, the patina lifecycle for Corten, fuel choices, UK smoke control area rules, and which size fits your patio.

Shop the Happy Cocoon 91cm Round Bowl — £549 →

The three garden fire pit materials

Almost every fire pit sold in the UK falls into one of three material categories. Each has a clear use case and clear failure modes. Understanding them is the difference between buying once and buying three times.

1. Powder-coated steel: the budget category

Most fire pits below £120 are powder-coated steel sheet, typically 1.5-2mm thick. The powder coat is a baked-on polyester or epoxy layer that gives the unit its colour and shields the steel from water. The format is usually a fire bowl on three or four legs, sometimes with cut-out decorative sides on a "fire basket" frame.

The good: cheap, light (8-15kg), easy to move, comes in dozens of decorative cut-out designs. The bad: 1.5-2mm steel deforms permanently after 4-6 fires once you get the metal cherry-red. The powder coat chips at any cut edge within the first year, exposing the steel, and rust spreads from there. A £60 unit lasts 18-30 months in regular use; a £200 unit with thicker 3mm steel lasts 8-12 years.

For more on how powder-coat finishes hold up across UK garden ornament metalwork, see our companion piece on metal garden ornaments rust finishes and care.

Shop the Cook King Boston 80cm Decorative Fire Bowl — £199 →

The Cook King Boston is the model we recommend most often in the powder-coated steel category. 3mm wall thickness, 80cm diameter, around 18kg, with decorative laser-cut star panels around the bowl that throw shadow patterns when lit. At £199 it sits in the upper end of decorative steel pricing because the wall is genuinely 3mm rather than the 2mm most competitors fit at this price point.

Shop the Cook King Montana 80cm High Fire Bowl — £219 →

If you would rather have the bowl at sitting-around-and-warming-hands height, the Montana raises an 80cm steel bowl on a tall stand. Same 3mm wall, same Cook King build quality, but the geometry suits a patio with people standing around the pit at chest height rather than sitting low. It also reduces the radius of scorched grass below the pit because the bowl is further from the ground.

Steel fire baskets: an alternative format

A "fire basket" is a steel cage rather than a sealed bowl. The advantage is airflow - the fire breathes from underneath as well as above, which gives you bigger flames and a faster burn. The disadvantage is that ash and embers fall through, which means you cannot use a basket on decking, lawn or anything you want to protect.

Shop the Cook King Verona 60cm Fire Basket — £89 →

The Verona pictured above includes an integrated ash tray - the fix for the falling-embers problem. The cage walls are a generous 50cm tall, which means you get a tall flame display without spitting embers onto the patio. At £89 it is the entry point to fire baskets and a sensible first fire pit for a smaller garden where you do not want the visual mass of a full bowl.

Shop the Cook King Flame 45cm Fire Basket — £99 →

The Flame is the same idea scaled down to 45cm - the right size for a 2-3 person courtyard or balcony where a 60cm pit would dominate. Steel walls, integrated ash plate, footprint just over half a metre square. At £99 it is the cheapest properly-built fire pit we stock, and a good choice if you are not sure how often you will use one.

2. Cast iron: the traditional category

Cast iron fire pits are made from molten iron poured into a sand mould and finished with a heat-resistant black coating. Wall thickness runs 6-10mm versus 2-5mm for sheet steel. The result is heavy (40-90kg for a typical 70cm bowl), retains heat for 30-45 minutes after the fire dies, and lasts 25-40 years if you protect it from standing water inside the bowl.

The good: longest lifespan of any fire pit material, classic foundry-made aesthetic, doubles as a heat sink so the patio stays warm after the flames are out. The bad: weight (one person cannot move a cast iron pit), shock-sensitive (drop it onto a hard surface and it can crack), and the price - genuine cast iron fire pits start at £350 and go to £1,500+ for ornate Victorian repro pieces.

The trade-off most UK buyers make is to choose Corten weathering steel instead, which gets you most of the lifespan of cast iron at half the weight and price. Genuine cast iron makes most sense if you want a permanent feature with foundry-quality detail, or you have a very traditional period garden where the look matters as much as the function.

3. Corten weathering steel: the premium category

Corten (a brand name now used generically for any A588 or S355J0WP weathering steel) is a structural alloy designed to develop a stable rust-coloured patina that protects the metal underneath. The patina is the protection - the steel will never rust through in any normal lifetime. Wall thickness for fire pits is typically 3-5mm. Weight sits between sheet steel and cast iron.

The look is the main draw. New Corten arrives slate-grey or dark blue. Within 6-8 weeks of UK weather it darkens to a uniform brown. By month 18 it has stabilised to the warm rust-orange that designer gardens use as a structural accent. From there the patina holds for decades. No painting, no rust treatment, no annual maintenance beyond emptying ash and hosing down occasionally.

Shop the Happy Cocoon 76cm Square Black Fire Pit — £439 →

The Happy Cocoon range is our flagship Corten line. The 76cm square pictured above is the size most UK family gardens settle on - big enough for a six-person seating zone, small enough not to dominate a patio. The "Black" finish here refers to the factory finish before patina; over the first 12-18 months it develops the same rust-orange that the older "Grey" variants already show. At £439 it is the upgrade pick over a steel bowl.

Shop the Happy Cocoon 61cm Round Grey — £305 →

The Happy Cocoon 61cm Round Grey is the model that lands in most gravel-and-grasses suburban gardens. Round footprint sits more naturally amongst informal planting than a square one, and 61cm is the right diameter for 4-5 people seated around the pit on garden chairs without anyone roasting their shins. The "Grey" finish here is the post-patina state - what your pit will look like at year two.

Shop the Happy Cocoon 60cm Small Square — £285 →

For courtyards and balconies the smaller 60cm square Happy Cocoon is the entry point to the Corten range. Same 3-4mm wall thickness, same patina development, same lifetime durability - just scaled to suit a 4-person max seating zone or a roof terrace. At £285 it is the lowest-cost piece in the Corten range and the model to buy if a Corten fire pit is your eventual aim but you are not ready for the £549 91cm bowl.

For more on how to choose between steel, cast iron and Corten in the broader context of garden metalwork, our pillar article on garden ornament materials covers durability and care across all garden metals.

Steel vs cast iron vs Corten: at-a-glance comparison

The Corten patina lifecycle

Buyers new to Corten often ask "is it meant to look like that?" at every stage. The answer changes month by month for the first two years. Knowing the lifecycle prevents you returning a perfectly normal pit because you thought it was rusting through.

If your Corten pit is in a covered porch or under a roof overhang, the patina takes longer because rain is the catalyst. Move it out into the open for the first 6 months if you want the patina to develop quickly. If you want to slow it down (e.g. for a contemporary garden where you prefer the slate-grey new look), keep it under cover and the mill finish will hold for 6-12 months.

The patina sheds a small amount of iron oxide in heavy rain during the first 6 months. This can stain pale paving below the pit. Either accept the staining as part of the look, or place the pit on gravel rather than light limestone or sandstone slabs.

Fuel types: what to burn

Most UK fire pits are designed for solid fuel - seasoned hardwood logs, smokeless coal, or charcoal. Some upmarket models run on gas (mains or LPG) with imitation log inserts. The choice affects flame appearance, smoke, ash, and what you can legally burn in your area.

• Seasoned hardwood logs: The default and best for ambience. Oak, ash, beech and birch all burn well. Moisture content under 20% (kiln-dried "Ready to Burn" certified). 2-4 hour burn from a 30cm log on a 70cm pit.
• Smokeless coal: Long burn, low smoke, low ash. Less ambient than logs. Useful for shoulder-season heat where you want warmth more than crackle.
• Charcoal briquettes: If you also use the pit for cooking. Higher heat per kilo, almost no smoke, leaves more ash than logs.
• Gas (LPG bottle or mains): Switches on and off instantly, no ash, no smoke, no Smoke Control Area issues. Lower heat output and missing the crackle. Best for urban roof terraces.

Never burn treated timber, painted wood, MDF, plywood, plastic, or rubbish in a fire pit. The fumes are toxic and the residues damage the metal. Also avoid softwood (pine, spruce) for prolonged use - it spits and tars the inside of the pit.

UK fire pit regulations and Smoke Control Areas

Fire pits are not generally regulated, but in Smoke Control Areas (much of urban England, Scotland, Wales and Northern Ireland) the Clean Air Act 1993 limits what you can legally burn. Local authorities enforce this with fines up to £300 for repeated breaches. Three rules apply:

1. You can only burn authorised fuels in a Smoke Control Area. The full list is on the DEFRA Smoke Control Area register. Wood must be "Ready to Burn" certified (under 20% moisture).
2. Solid fuel can only be burned in an exempt appliance in some boroughs. Standard open fire pits are not exempt appliances - check your local council before you buy.
3. Smoke from any source can be reported as a statutory nuisance under the Environmental Protection Act 1990 if it affects neighbours. Common sense applies regardless of Smoke Control Area status.

Outside Smoke Control Areas the rules are looser, but the neighbour-relations ones still apply. Avoid early morning fires when neighbours have washing out, do not leave smouldering fires unattended overnight, and respect dry-summer hosepipe-ban warnings around fire risk.

How to size a fire pit to your space

The single most common return reason on fire pits is "it is too small once we sit around it". The seating zone that feels right around a 60cm pit is usually a metre wider than people expect. The rough rule:

• 45-60cm pit: 2-4 people seated, 2.5m clear circle around the rim, balcony or courtyard scale.
• 61-76cm pit: 4-6 people seated, 3m clear circle, suburban patio scale.
• 76-91cm pit: 6-8 people seated, 3.5-4m clear circle, large patio or fire pit zone.
• 91cm+: 8+ people, 4m+ circle, dedicated fire pit area on a lawn or gravel terrace.

The "clear circle" is non-negotiable for safety. No furniture, no cushions, no overhanging garden structures inside that radius. UK insurance policies that cover garden fire often require a 1m clear margin around the pit; check your policy wording before lighting up the first time.

Matt's Pick

Matt's Pick for Most UK Gardens Best For: A typical 4-6 person suburban patio that wants real flame ambience without committing to Corten Why I Recommend It: The Cook King Indiana 70cm hits the sweet spot between size, build quality and price. 3mm steel wall, 70cm bowl diameter, integrated stand, and at £119 it is the most-bought fire pit in our range. Burns logs cleanly, holds heat well, light enough to move (around 14kg empty), and the bowl shape is generous enough that ash and embers stay contained without an extra tray. If your aim is "fire pit for autumn drinks on the patio without overthinking it", this is the one. Price: £119 View Product

Year-round care and maintenance

A well-cared-for fire pit lasts decades. Five rules:

1. Empty ash within 48 hours. Wet ash sitting on the bowl base is the single biggest cause of premature corrosion. Use a metal ash bucket and dispose once cold.
2. Cover or invert when not in use. A fitted cover stops rain pooling inside the bowl. If you have no cover, invert the pit so it sheds water.
3. Touch up paint chips on powder-coated steel within a month. A £6 tin of high-temperature stove paint stops rust spreading from any chip. Apply on a dry day above 10°C.
4. Do not paint or seal Corten. The patina is the protection. Sealing it stops the chemistry working and creates pockets of corrosion underneath.
5. Inspect cast iron for hairline cracks each spring. Cracks usually start at handle attachment points or the bowl base. Catch them early and the pit can be welded; ignore them and the next thermal cycle widens them.

Browse our full garden fire pits range for steel bowls, fire baskets, and the full Corten weathering steel collection from 60cm courtyard pits to 91cm centrepiece bowls.

Frequently asked questions

What is the best material for a UK garden fire pit?

Corten weathering steel is the best material for UK gardens that want a lifetime piece. It develops a stable rust-coloured patina in 18-24 months and never needs painting. Powder-coated steel is the right choice for casual use under £200. Cast iron suits period properties where weight and traditional foundry detail matter. Avoid 1.5-2mm thin sheet steel - it warps within 2-3 winters.

How thick should the wall of a fire pit be?

Aim for 3mm minimum on steel, 6mm+ on cast iron, 3-5mm on Corten. Below 3mm the metal deforms permanently after repeated cherry-red heat cycles. The price gap between a 2mm and 3mm fire pit is typically £60-£100, but the lifespan difference is 5-7 years. Wall thickness is the single most important spec.

Can I use a fire pit in a UK Smoke Control Area?

Yes, but only with authorised fuels. "Ready to Burn" certified seasoned wood (under 20% moisture) and smokeless coal are permitted. Some boroughs require an exempt appliance for solid fuel - standard open fire pits may not qualify. Check the DEFRA Smoke Control Area register before lighting. Gas fire pits avoid the issue entirely because they emit no smoke.

How long does a Corten fire pit take to weather?

Corten reaches its stable rust-orange patina at 18-24 months in a UK climate. The first patchy bloom appears at week 4-6, even darkening sets in by month 6, and the lifetime patina forms at month 18-24. Pits kept under cover or indoors take longer because rain is the catalyst. The patina then holds with no further visible change for decades.

What size fire pit do I need for 6 people?

A 70-76cm bowl is the right size for six people seated around a fire pit. Allow a 3m clear circle around the rim for safety and chair placement. Smaller bowls (60-65cm) work for 4 people; larger bowls (80-91cm) suit 8+ and need a 3.5-4m clear radius. Always size up if your group regularly varies between 4 and 8 people.

Related reading

• The Complete Guide to Garden Ornament Materials
• Metal Garden Ornaments: Rust Finishes, Weathering and Care
• How to Protect Garden Ornaments in Winter
• Summer Garden Styling: Creating the Perfect Outdoor Living Space
• Garden Furniture Buying Guide UK 2026

Browse our full collection of garden ornaments for fire pits, water features, statues and outdoor pieces to round out the patio.