Canberra Building Inspections. Hills outside Canberra.

Slab  Inspections

My Canberra Building Inspections ACT

Pre Pour Slab Inspection

This is possibly the most important inspection you can get. Here is why.

Your house concrete slab is being built by subcontractors who do not have to warrantee their work with the house owner. The building supervisor might be really good, or he might just be really busy somewhere else on the day of that pour. Supervisors are generally good people. Most builders are as well. So are most certifiers.

Inspections for Builders

We have also done inspections for builders, not just for clients. Our inspector is a Class A Builder. He was recently asked by a builder to inspect their slabs before the pour as the certifier was just too easy, and, the builder wanted a tough exacting report to get the certifier to be tough on him. I saw what was approved, and the builder was right. It should not have been approved.

Certifiers are key

Certifiers need to be tough. Some are tough, and that makes it easier for the builder to work with tradesmen. A standard goes up, or goes down. It never stays the same. We all decide on that.

It is the builder who is responsible for the building construction. But he relies on the certifier to hold some of the trades in check. Most trades people are good though. But sometimes, younger ones, need more pressure on them. A good certifier helps with that.


Many times I see reinforcing bar touching the external side boards of the concrete floor space. And it is approved when it should not be.

There is meant to be 20 mm or so concrete cover. So how can the reinforcing boards be allowed to touch the steel? That means that the steel will be directly exposed to the air, and rain, and can sit in water for much of the winter, year after year. Rust will then slowly creep inside your building, under your floor, for a lot longer than any structural guarantee the builder or insurance provides.

Foam preventing steel cover in trench

Foam in trench preventing concrete cover.

Longevity of Houses

How long should your house last? I would suggest 120 years for a single storey house, and 150 years if it is double storey. Your house needs to be built to these parameters. Enforce it with efficient inspections.

The foam box inhibiting concrete cover

Foam box inhibits concrete cover

The steel also should have specified cover all around it. It should not touch the ground. Steel should not be sitting on the polythene sheeting. Reinforcing steel should be placed on the chairs provided. It should not be touching the foam. And there are many more don’ts.

How Concrete and Steel Strengthen Each Other

Concrete and steel need to give strength to each other. One acts in compression and the other acts in tensile. It is a little like a human body that has both muscle and bone. One without the other working properly will create weakness and eventual failure.

Post Pour Slab Inspection

After your slab is poured, you should have another inspection. The client can do this. Why is it needed? It is because when the concreters are pouring the slab you want to be sure those trades people are doing the job right. The best way you are going to do that is to monitor the pour as it pours, which is the supervisor’s job. The next best is to have an inspection after the pour is done, and after the slab side boards are off.

Exposed Steel

This inspection, which the client can do, can reveal steel that was once looking great in the Pre-Pour Inspection, but which was knocked around and kicked over during the pour, and left sticking out, again, to rust. What a supervisor should do if this is found is do something to rectify it. The last thing wanted now is to have steel corrode over the next several decades.

Most builders will care about this for the sake of the building.

Slab steelwork exposed

Slab steel exposed after the pour.

The solution is to put pressure on the builder. You do that with this report. It does not take long to do the inspection and report it. But if there is steelwork exposed, after the pour, what do you do? That is the builder’s job to solve.

When the report is done fast, the builder will find out before he pay’s his subcontractors. He can then back-charge them what it costs to fix, and likely they will take more care on the next slab they pour.

When no Action is Taken

If nothing is done by the builder in a reasonable time you can also report it to the ACT government and they can read the report and then see for themselves. They can take it further.

It is serious.

Reinforcing without cover

Reinforcing found under another slab that did not get concrete around it.

But to be fair on the subcontractor, and his crew, they are dealing with heavy concrete coming out from the end of the pump boom. They are also trying to balance on the reinforcing like a spider on his web. It is not easy. So errors occur. It’s not intentional. Understand that. But the point is, when errors happen, know about them so they can be fixed.

Also see the prices page.

Extra Reading

There is more here on this Access Canberra page on how to resolve disputes.

“As soon as you identify an issue or have a concern, raise this with your builder in writing. Your builder should take steps to address your concerns. If the issues are not resolved and are about building or planning of a technical compliance nature, and construction is still underway talk to your building certifier and consider making a complaint to Access Canberra. The building certifier is appointed by the land owner and not the builder. They work in the interest of achieving compliance with the relevant building and planning laws.”

And This Here

“If your concerns relate to your contract, such as issues with payments, quality of inclusions, or communication, you can contact:

Full List of Building Stages

Also see more about the full list of building stages and contracts below. We would recommend five of those be inspected. The bigger the house the more inspections we recommend you have.

     Your Building Contract

Slab Inspection

…..Frame Inspection

…..Facade Inspection

…..Roof Inspection

…..Lock Up Inspection

…..Pre Lining Inspection

…..Fixing and Fit Off Inspection

…..Practical Completion Inspection

…..Ninety Day Defect Liability Inspection

Worksafe ACT

To report unsafe work practices, such as faulty scaffold, please contact Worksafe ACT.

We hope this page helps you.

Written by: Nick Broadhurst, building inspector, registered Class A Builder, Bach. Arch. UWA. For more information on Nick: See here

Nick Broadhurst building inspector on top of a roof.

Call us today for your next Building Inspection.

We will answer your questions. Our Building Inspector is registered here at Access Canberra. No. 111.

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