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Can I Pour a Concrete Slab Myself? DIY vs Hiring a Concreter

The honest answer on what's realistic, what it really costs, and when to pick up the phone

Published 16 June 2026 • 8 min read

The Honest Answer: Yes, But Most People Regret It

If you're handy, fit, and willing to put in the hours, you can absolutely pour a small concrete slab yourself. People do it all the time. The question isn't really "can I" but "should I, and at what size, and is the result going to be any good?"

The honest truth from years of doing this work: most DIY concrete jobs we get called out to fix would have cost less to have done properly the first time. The pour itself is the easy part. Everything around it (the prep, the formwork, the timing, the finishing) is where it goes sideways for first timers.

This article gives you the straight story on what's realistic for DIY, where it usually goes wrong, and the size where you really do need to put the trowel down and call a concreter.

What Size Slab Is Realistic for DIY?

If you've never poured concrete before, the upper limit for a first attempt is about 2m x 2m at 100mm thick. That's around 0.4 cubic metres of concrete, or 20 standard bags. It's small enough that you can place and finish it before it goes off, and small enough that mistakes don't cost a fortune to fix.

Here's a rough realism guide:

The reason size matters so much is that concrete starts setting from the moment water hits the cement. Once it starts going off, you can't fix mistakes. A small slab gives you a forgiving window. A big one does not.

What You'll Need: Tools, Materials, Time, Helpers

For a 2m x 2m DIY slab at 100mm thick, here's the rough shopping list.

Tools (most will need to be hired or borrowed):

Materials:

Helpers and time:

You need at least 2 to 3 people on pour day. One can't do it alone, full stop. Plan for one weekend of prep work (digging, base, formwork, mesh) and a second day for the actual pour and finish. Allow 24 to 48 hours before walking on it and 7 days before any load.

The Real Cost of DIY (Spoiler: It's Not as Cheap as You Think)

Most DIYers compare the cost of bagged concrete with the cost of a quoted job and conclude they're saving thousands. The maths usually doesn't survive contact with reality.

For a 3m x 3m shed slab as an example:

That's $700 to $950 in materials and hire alone, before you've counted your time or any mistakes. A professionally poured slab of that size is often in the same ballpark once you account for the quality difference and the lack of risk.

All prices are indicative starting from guides only. Final pricing depends on site conditions, access, soil type, and specific requirements. See our pricing guide for current ranges.

Where DIY Concrete Usually Goes Wrong

These are the failures we see most often when called to fix a DIY job:

1. Subgrade prep is rushed or skipped

Soft spots, organic matter still in the ground, or no compaction means the slab sits on an uneven base. Within a year you get differential settlement and cracking. Proper prep means 75mm to 100mm of compacted road base over firm ground.

2. Formwork that bows or moves during the pour

Wet concrete is heavy. Around 2400kg per cubic metre. If your form timber isn't well staked and braced, the sides bulge out during the pour and you end up with a slab that's wider at the bottom than the top, with a wavy edge.

3. Mesh sitting on the ground

Reinforcing mesh only works if it's in the middle of the slab. Mesh laid straight on the plastic does almost nothing. You need bar chairs spaced every 600mm to lift the mesh to the middle of the pour.

4. Getting it level

Screeding a slab flat is a skill. Without a bull float and proper screed technique, DIY slabs tend to dish in the middle or pond water at the edges. Once it's set, you can't fix this without grinding or pouring a topping.

5. Finishing in the Brisbane heat

This is the big one. On a 30 degree summer day, concrete can go off in 90 minutes. Inexperienced finishers either touch it too early (and pull the surface apart) or wait too long (and can't get a finish on it at all). Picking the right time of year to pour matters more than people realise.

6. Curing

Concrete doesn't dry, it cures. It needs moisture to develop strength. Pouring on a Saturday, then ignoring it until the shed gets delivered next week is the fastest way to a weak, dusty slab. Keep it wet or covered for at least 7 days.

Time Honesty: The "Weekend Job" Trap

When someone asks "how long will it take me to pour a small slab?" the answer in their head is usually "a Saturday." The actual answer for a first time DIYer:

That's a fortnight of part time work for what was supposed to be a Saturday job. And that's if nothing goes wrong.

What You Save vs What You Risk

Best case DIY: you save a few hundred dollars and get a slab that's acceptable for a small shed or garden use. You learn a useful skill and feel good about the project.

Worst case DIY: the slab cracks, ponds water, isn't square, isn't flat enough for a kit shed to bolt down properly, or comes up dusty and weak. Now you've got three options. Live with it. Pour a topping over it (which rarely works well). Break it out and start again, which now costs more than the original quote would have.

We get a steady flow of "second pour" jobs every year. People who tried DIY, didn't like the result, and called us to fix it. Almost always the rework costs more than the original job would have, because we have to demolish and remove the failed slab first.

When DIY Actually Makes Sense

DIY concrete is a perfectly good choice for:

If the slab is small, low load, hidden, and not structural in any way, DIY is reasonable. Even then, do your homework first.

When You Should Hire a Concreter

Call a pro for:

The "Second Pour" Reality

One of the most common phone calls we get goes like this: "We poured a slab last weekend and it's gone wrong. Can you come and fix it?"

The honest answer is usually no, not easily. Once concrete has set, your options are limited. You can grind a high spot. You can patch a hollow with self levelling compound. You can pour a thin topping if there's clearance. But fundamentally, if the slab isn't level, isn't square, ponds water, or has the mesh in the wrong place, the only proper fix is to break it out and start again.

The point of mentioning this isn't to scare you off DIY. It's to set expectations. If you do go DIY, accept that the result is what you get. Don't pour a slab thinking "if it goes wrong I'll just call a concreter." That call gets very expensive.

How a Concreter Does It Differently

The big differences between a pro pour and a DIY pour aren't really about strength. Mix is mix. The differences are in the process:

It looks simple when someone with 1000 pours under their belt is doing it. It isn't.

The Brisbane Heat Factor

This deserves its own section because it catches more DIYers than anything else. From October through March, a slab poured at 9am can be touching off (starting to set) by 11am and basically unworkable by 1pm. That's a 4 hour window to place, screed, float and broom finish a slab while it's actively trying to set on you.

Experienced concreters work with this. They start earlier, time the delivery to the conditions, use retarder if needed, and have enough hands to move fast. A DIYer pouring in the middle of a summer day usually loses the surface to the heat before they can finish it. The result is a slab that looks like the moon. Bumpy, rough, with all the cream pulled out.

If you're set on DIY, pour in autumn or winter. Brisbane between May and August is your best window. Hotter than that and you're fighting the weather as well as the concrete.

Important Disclaimer

This article is general information only. Site conditions, soil type, slope, access and intended use all affect what's appropriate for a particular slab.

We specialise in small concrete jobs only: shed slabs, garage slabs, concrete footpaths, water tank slabs and small pads. For larger structural work, consult a suitably qualified professional.

All prices mentioned are indicative starting from guides only. Final pricing depends on site conditions, access, soil type and specific requirements.

Before You Decide, Work Out the Numbers

If you're weighing up DIY versus a quote, do these two things first:

  1. Use our shed slab calculator to work out exactly how much concrete you need and what the materials will cost.
  2. Read how much concrete a typical shed slab needs so you know whether you're in bagged mix territory or ready mix territory.
  3. Skim our common mistakes with small concrete jobs guide to see what to avoid.

Then get a real quote from a concreter for comparison. Contact us for an obligation free price on small concrete work. Often you'll find the gap is smaller than expected once you account for hire gear and your time.

Common Questions About DIY Concrete

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