How To Build a Fire Pit
How do you build a backyard fire pit?
Check the Liquid Nails Landscape specification
Selleys' product page and its dated technical sheet disagree on Landscape's chemistry, colour, paintability and pack size. Landscape figures below from the November 2020 technical sheet describe that document, not a confirmed specification for every current cartridge. Confirm the matching instructions before painting, choosing a colour, or relying on cure and loading times. See the source comparison and dated documents.
The source guide describes this fire-pit build, subject to confirming the adhesive and design for heat exposure: mark out a circle, dig and level the base, lay concrete blocks around the perimeter, bond each course to the one below with Selleys Liquid Nails Landscape, then drop a steel fire bowl or metal fire pit ring inside. No mortar, no bricklaying skills, and the only measuring tool you really need is a spirit level.
Do not treat the product-page temperature figure or the presence of a steel bowl as proof that an adhesive joint is suitable for a fire pit. Confirm the adhesive's suitability for the proposed design and heat exposure with Selleys before building or lighting it. Keep adhesive away from flame and ignition sources.
What you need
- Selleys Liquid Nails Landscape and a caulking gun
- Concrete blocks
- A large steel fire pit bowl or fire pit ring
- Decorative rock for the base
- Spray paint to mark out
- Shovel
- Spirit level
Why Liquid Nails Landscape is the right adhesive here
Liquid Nails Landscape is a premium-grade, high-strength construction adhesive that delivers a weather-resistant, flexible, shock-proof bond. It is supplied in a 300 gram grey cartridge, and it is formulated for exactly this class of work — stabilising stone and interlocking masonry retaining walls, bonding pavers to concrete, bonding capstones to walls, repairing rockeries, sealing between treated pine logs, and stabilising loose stone steps. For Landscape, confirm the specification for your cartridge: the manufacturer sources disagree.
| Technology | Neutral cure silicone |
| Colour | Grey |
| Specific gravity @ 25°C | ~1.35 |
| Skin time | 10–15 minutes |
| Tack free time | 35 ± 5 minutes |
| Cure rate | 2 mm / 24 hours |
| Slump | < 0.1 inch |
| Shore A hardness | ~30 |
| Elongation at break | >300% |
| Service temperature | Confirm heat-exposure suitability with Selleys; not established by the 2020 TDS. |
Indicative data only, not intended for preparation of specifications.
What the key numbers mean when you are laying blocks
A 10–15 minute skin time is short, and it dictates your rhythm. The data sheet asks you to bring the surfaces together within 5 minutes of applying the adhesive — before the product skins. So work one block at a time: apply, place, level, then move on. Do not run a bead along an entire course and then start setting blocks.
Elongation over 300% and a Shore A hardness of about 30 tell you this is a flexible bond rather than a rigid one. That is deliberate. A rigid mortar joint between concrete blocks cracks when the ground moves or the blocks expand differently in the sun; a flexible bond absorbs it. It also means the joint is shock proof, which matters on something people will knock with chairs and firewood.
A 2 mm per 24 hour cure rate is a depth figure. The data sheet asks you not to allow traffic on stairs or use walls for at least 24 hours after bonding, and the same logic applies here: build it, then leave it a day before you light anything.
How to build it
- Mark out the circle. Use spray paint on the lawn to mark where you want the pit to go.
- Dig out the lawn inside the circle to a depth of about 2 cm, removing all roots.
- Check the base is flat with a spirit level. Everything above this depends on it — a base out by a few millimetres becomes a visibly leaning wall three courses up.
- Lay the first course of concrete blocks along the perimeter of the fire pit.
- Build up the remaining courses to your desired height, using Liquid Nails Landscape to bond the layers together. Apply dobs or beads of adhesive thick enough to give good contact and spread between both surfaces, keeping the adhesive at least 12 mm in from the edges to minimise squeeze-out. Bring the block down onto the bead within 5 minutes and apply enough pressure to spread the adhesive between both faces. Check each course with the spirit level as you go. For Landscape, confirm the specification for your cartridge: the manufacturer sources disagree.
- Place decorative rock at the base of the fire pit.
- Set the steel bowl or metal fire pit ring inside. Make sure it is level and will not tip over.
- Leave it to cure before use. The data sheet asks that bonded walls not be used for at least 24 hours.
Two application details worth getting right
Do not wipe the squeeze-out. The data sheet is explicit: wait until the product cures and remove it by trimming with a sharp blade, taking care not to cut into the bond. Wiping wet adhesive smears it across the block face where it is far harder to remove. Spilt or smeared adhesive is best left to cure and then removed by abrasion.
If you reposition a block, apply fresh adhesive. Lifting a block off a skinned bead and putting it back gives you no bond at all. That is a stated note on the data sheet, not a nicety.
Limitations — what to be careful about
- Service temperature -20°C to 100°C. Keep the fire inside the steel bowl or ring so the adhesive is never exposed to direct heat or flame. Do not build the design so that burning fuel sits against a glued joint.
- Not for soft or crumbly materials. Weathered, flaking blocks will not hold a bond regardless of the adhesive.
- Not for permanent water immersion.
- Cannot be painted over. If you plan to paint or render the blockwork, the adhesive joints will not take the coating.
- Do not use it as the sole bonding agent for structural bonding. This design relies on the weight of stacked blocks; do not extend it into a tall retaining wall on adhesive alone.
- Surface preparation matters. The blocks must be sound, dry and free from oil, grease and loose powdery material — use mineral turpentine to clean the surface if necessary and allow it to dry.
Clean up and storage
Uncured adhesive can be removed with mineral turpentine. Cured product can be removed with the help of Selleys Sealant Remover or by mechanical action. Store the cartridge in a cool, dry, well-ventilated place out of direct sunlight and away from foodstuffs.
Liquid Nails Landscape's Australian SDS version 7.0, 16 November 2023, lists Danger: H227, H317 and H318 — combustibility, allergic skin reaction and serious eye damage. Follow the matching pack and SDS for protection, handling and first aid.
Common questions about building a fire pit
Can I light a fire directly on the blocks?
A steel bowl or ring alone does not establish the temperature at the adhesive joints. Confirm the design and adhesive suitability with Selleys before use.
Do I need mortar as well?
No. The guide bonds each course to the one below with Liquid Nails Landscape and relies on the weight of the blocks. The adhesive should not be used as the sole bonding agent for structural bonding, so keep the build low and stable rather than tall.
How long after building can I use the fire pit?
At least 24 hours. The data sheet asks that bonded walls not be used, and traffic not be allowed on bonded steps, for at least 24 hours.
How quickly do I have to place each block?
Within 5 minutes of applying the adhesive, before the product skins. Skin time is 10–15 minutes and tack-free time is 35 ± 5 minutes.
How deep should I dig?
About 2 cm inside the marked circle, removing all roots, then check the base is flat with a spirit level.
What do I do about the adhesive squeezing out between blocks?
Leave it. Wait until it cures, then trim it with a sharp blade, avoiding cutting into the bond. Applying the adhesive at least 12 mm in from the edges reduces squeeze-out in the first place.
Can I move a block after I have set it?
Only by applying fresh adhesive. Repositioning onto a skinned bead will not bond.
Can I paint or render the finished pit?
Liquid Nails Landscape cannot be painted over, so the joints will not take a coating. For Landscape, confirm the specification for your cartridge: the manufacturer sources disagree.
Will it survive being rained on?
Yes — the adhesive is weather resistant and rated for outdoor use. It is not suitable for permanent water immersion, so do not site the pit where it will sit in standing water.
What if my blocks are old and crumbly?
The data sheet says the product is not for soft or crumbly materials. Clean and sound blocks are a requirement, not a preference.
How do I get the adhesive off my hands?
Mineral turpentine while it is uncured. Once cured, it has to be abraded off.
What else can I use this adhesive for?
Bonding pavers to concrete, capstones to walls, stabilising loose stone steps, repairing rockeries and sealing between treated pine logs to reduce soil loss.
What materials are needed to build a fire pit according to Selleys' guide?
According to Selleys, you need concrete blocks, a shovel, a spirit level, spray paint, Selleys Liquid Nails Landscape, decorative rocks, and a large steel fire pit bowl or fire pit ring. This describes the source guide, not a verified heat rating. Confirm the adhesive and proposed design with Selleys before building or lighting the fire pit.
How long does it take to build a fire pit using this Selleys guide?
The Selleys guide estimates the fire pit project takes about 2 hours to complete.
What skill level is required to build a fire pit using this guide?
The guide lists the project as suitable for Beginners, Intermediate, and Advanced skill levels.
What is the first step in building a fire pit according to Selleys?
The first step is to use spray paint to mark out your lawn where you want the fire pit to go.
How deep should you dig when preparing the ground for a fire pit?
You should dig out the lawn inside the marked circle to about 2cm deep, making sure to remove all roots.
What product is used to bond the concrete block layers together when building a fire pit?
Selleys Liquid Nails Landscape is used to bond the concrete block layers together as you build the fire pit to your desired height. This describes the source guide, not a verified heat rating. Confirm the adhesive and proposed design with Selleys before building or lighting the fire pit.
How do you ensure the concrete blocks are level while building the fire pit?
You use a spirit level throughout the process, first to ensure a flat surface before laying blocks, and then again while building up the layers to make sure the blocks stay level.
What goes inside the fire pit once the concrete blocks are built up?
Decorative rock is placed at the base of the fire pit, and a large steel bowl or metal fire pit ring is placed inside, ensuring it is level and will not tip over.
What is Selleys Liquid Nails Landscape used for?
Selleys Liquid Nails Landscape is an adhesive designed for outdoor projects, perfect for bonding rocks, stones, and similar materials.
What other outdoor project guide does Selleys offer alongside the fire pit guide?
Selleys also offers a 'How To Build a Deck' guide, which shows how to build a custom deck perfect for your outdoor space.