One person alone screeding a backyard slab that is going off faster than they can finish it
Doing It Yourself

Concrete Is the Worst Trade to Learn On

There is a version of this article written by every concreter in the country and most of them are really an advertisement. So here is the honest one, including the part where we tell you which concrete jobs you genuinely should do yourself and save the money.

1 September 20268 min read

The Short Version

  • Concrete does not wait, and that, not skill, is what makes it hard
  • The base is the most common failure and the least visible one
  • A cubic metre is roughly twenty wheelbarrow loads
  • Small pours are genuinely worth doing yourself, and we will help you get them right
  • A slab that fails costs three times: the slab, the removal, and the replacement

The Problem Is Not the Skill. It Is the Clock

Almost every trade around a house forgives a slow learner. Paint dries and you can sand it back. Tiles come up. Timber can be unscrewed and cut again. You can stop at four in the afternoon, look at what you have done, and fix it on Saturday.

Concrete does none of that. From the moment it is batched it is going off, and the window you have to place it, level it, and finish it is measured in hours and shrinks with heat and wind. A truck arrives with several tonnes of a material that will not wait, and everything you did not think about beforehand has to be solved while it is going hard in front of you.

That is the whole difficulty of this trade, and it is why experience matters more here than in almost any other job on a house. Not because the individual steps are clever, but because there is no time to work anything out.

What Actually Goes Wrong

Not a list of things that could theoretically happen. This is what we get called out to look at.

The Base Was Levelled, Not Compacted

The most common one by a distance and the most expensive. Loose fill looks perfectly flat when you rake it. Under a slab it settles unevenly, and the slab cracks where it loses support. You will not see the mistake for a year or two, and by then it is not fixable, only replaceable.

It Was Ordered by Guessing

Concrete is sold by the cubic metre and the difference between what you estimated and what the hole actually takes is not academic. Short, and you have a cold joint across the middle of your slab forever. Over, and you are paying to dispose of it in the twenty minutes before it goes off in the drum.

Nobody Thought About Where It Comes In

A truck chutes about three metres. If the pour is out the back, the concrete gets there by wheelbarrow, and a cubic metre is roughly twenty barrow loads. Two people and a wet Saturday is how a small back yard slab becomes the worst day of the year.

The Steel Sat on the Ground

Reinforcement does nothing lying on the base. It has to sit up in the slab on bar chairs, and it is very easy to walk it down into the sub-base while you are placing concrete around it. A mesh you cannot see is a mesh that is not working.

It Was Finished Too Early, or Too Late

Trowelling a surface before the bleed water has gone seals water into it and gives you a slab that dusts and flakes. Leave it too long and you cannot close it at all. The window between those two is not marked and it moves with the weather.

Nothing Was Cut, and Nothing Was Cured

Concrete shrinks as it cures and it will crack. Control joints decide whether that crack happens in a straight sawn line where you put it or across the middle where it feels like a fault. Cutting them is a same-day job, and curing properly is another few days of attention after the exciting part is over.

What Is Reasonable to Do Yourself

We would rather you did the small jobs than paid us for them. This is roughly where the line sits.

The jobHonest verdictWhy
Stepping stones or a small padDo it yourselfBagged mix, no truck, no clock pressure
A shed pad under about 6m²Reasonable with helpSmall enough to place before it moves
A garden pathReasonable, with a caveatFalls and joints still decide how it ages
A drivewayGet a contractorVolume, base and finish all at once
A house slab or footingsGet a contractorIt is structural and it is inspected
Anything you cannot reach with a chuteGet a contractorThe barrowing is the job, not the pour

Worth saying about the top half of that table: small does not mean the rules change. A stepping stone still cracks if it sits on soft ground, and a shed pad still needs the base compacted and the falls right. What makes those jobs safe to attempt is the size, not that the preparation stops mattering. If you want to have a go, ring us and we will tell you how much to order and what to watch for.

Twenty Minutes Decides Which One You Get

The same side path at the same house, in the same light. The only difference is who poured it. Everything wrong on the left happened in the twenty minutes after the concrete stopped being workable.

Poured by the ownerA badly poured DIY concrete path with puddles, boot prints, cracks and an uneven edge
What Going Slow Looks LikeWater sitting in the dips because the fall was lost, a boot print set in the corner, a cold joint where the second load went off before it was worked in, and crazing across the surface from finishing it too early. None of it can be sanded out.
Poured by a crewA professionally poured concrete path, flat with an even broom finish, straight edges and a clean saw cut joint
What the Same Path Should BeOne flat plane with the fall running the right way, an even broom finish for grip, a straight edge against the lawn and a saw cut joint put in on the day so the slab cracks where it is told to.

The Part That Makes It Different From Other Mistakes

A bad paint job costs you a weekend and some paint. A bad tiling job costs you the tiles. A bad slab costs you the slab, the removal of the slab, and the new slab, and the removal is often the most expensive line of the three because it is a day of breaking out and carting away material that is now rubbish.

That asymmetry is the real argument, and it is worth being clear that it is an argument about risk rather than about talent. A careful person with time and a small pour will very likely be fine. The same person on a driveway, on a hot day, with a truck waiting and no one to help finish, is not making a skill mistake. They are taking a bet with the odds against them and no way to fold.

The reason a crew makes it look easy is not that the steps are simple. It is that four people who have done it a thousand times are all doing their part at once while the clock runs.

If You Are Going to Do It Anyway

Then do it on the smallest thing you own. Pour a stepping stone before you pour a path, and pour a path before you go near a driveway. Every mistake in this article is much cheaper to make in a wheelbarrow than in a truckload.

Order more than you think, by a margin. Have more people than you think you need, because finishing is where hands run out. Start early on a cool day, have the formwork and the base done and checked the day before, and have everything you need on site before the truck is called, because you will not be leaving to get it.

And if it is a driveway, or it is a structural slab, or it is behind the house, get a price. It is free, it takes twenty minutes, and worst case you find out the job was smaller than you feared and you do it yourself with better information.

Now You Know What to Ask

Send us the size and where it is. We will come out, measure the real thing and put a number in writing.

Get a Priceor call (03) 6724 3698
Keep Reading

More Guides

Everything else we have written down, in the same spirit as this one. How the job actually works, what it costs, and where people get caught out.

All guides
The Next Step

Get Your Job Priced

Send the size and where it is, or ring us. We come out and measure it properly, free either way.

Free Measure & Quote
Tell us what you need and we'll have a look.

What Happens After You Send It

  • We come out and measure it, free, and look at the ground and the access.
  • You get one written price for the whole job, not a rate per square metre.
  • If you go ahead, you get a start date and the same crew from quote to pour.

Would rather talk it through? (03) 6724 3698, or send the details through the contact page.

Common Questions

Questions We Get Asked About Doing It Yourself

Is concreting actually hard, or is that just what concreters say?

The individual steps are learnable in an afternoon. Doing all of them correctly, in the right order, in the time concrete gives you, is the hard part. That is why the same person can succeed on a stepping stone and come unstuck on a driveway.

Can I hand mix a driveway with bags?

Not sensibly. A modest single driveway is several cubic metres, which is well over a hundred bags, and every batch you mix separately is another chance for the colour, the strength and the finish to differ. Bagged mix is for small pours.

How much concrete do I actually need?

Length by width by thickness in metres gives you cubic metres, then add for the base being uneven, which it always is. Getting this wrong in either direction is expensive, so if you are ordering a truck it is worth having someone check the number before you place the order.

What is the single most common DIY mistake?

The base. It is the part nobody watches, it is finished before anything interesting happens, and it is the part that decides whether the slab cracks. Levelled is not the same as compacted.

Will you help if I have started and it has gone wrong?

Yes, and we would rather look at it early than after another winter. Sometimes the answer is a repair, sometimes it is cutting out a section, and sometimes it is that the slab has to come out. We will tell you which one it is.

Free Measure, Fixed Price

Find Out What Your Job Costs

One call and we come out, measure the real thing and put a price in writing. It costs nothing and there is no salesman in it.

One call. We measure it and put a fixed price in writing. Costs nothing.

(03) 6724 3698 Ask for a free measure
  • We come and measure itOn site, tape out, so the price is for your job and not a guess off a photo.
  • A fixed written priceOne number you can hold us to. Not a range, not a rate, not an estimate.
  • The crew who quotes it pours itThe bloke standing in your driveway is the bloke who does the work. Who you are dealing with.
  • Measured on site, not guessed
  • Fixed written price, not a range
  • The crew who quotes it pours it

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