Category Archives: Tips & Tricks

Tips and tricks for building in Queensland.

Residential Concrete Driveways

If you are after some definitive advice on residential driveway slab thickness, reinforcement and joint spacing then you have come to the right place. Check out this Residential Concrete Driveways and Paths manual produced by Cement Concrete and Aggregates Australia.

At Cornell Engineers we have been referring to this document since its release in 2006 and it’s still the best way to ensure satisfactory performance of your driveway slab. Remember that in the absence of better information, this is the manual that will be referred to in the event of a dispute about uncontrolled cracks in your driveway.

Don’t forget local authorities (councils) have their own requirements for driveways, cross-overs and paths. For example, here is the link to the Driveway Technical Standards for Brisbane City Council:

In you would like us to design a driveway slab for you please contact Matt Cornell of Cornell Engineers on 07 3102 2835.

If you have a cracked driveway slab, maybe we can help you. Call Matt Cornell for advice or to arrange an inspection.

Driveway Slab Reinforcement

Steel reinforcing mesh is used in driveway slabs to control the width and length of cracks in concrete. If the mesh is “walked in” or placed at the bottom of the concrete slab, it is ineffective and won’t control cracks. Ensure your mesh is correctly positioned when pouring by chairing it on bar chairs at 1000 x 1000 centres.

I was also asked recently if driveway slabs need the black plastic membrane (200 micron polyethylene membrane) under them before pouring. If you have the plastic on site, then I recommend using it. The purpose it serves is to prevent the dry ground sucking moisture out of the wet concrete. That moisture is needed by the cement powder in the chemical reaction called hydration. Don’t worry if your driveway slab has already been poured without the plastic membrane. Not having it won’t decrease your slab’s strength too much.

Got a structural engineering question? Ask us on the contact page or comment here!

Matt Cornell
Cornell Engineers

Building over sewers

Build over a Sewer

The rules for building near existing council-owned buried infrastructure (including sewer mains, stormwater pipes and underground electrical cables) vary from region to region. There are two main reasons for these rules.

  1. They want to be able to access their pipes safely;
  2. They don’t want your structure to collapse into their trenches.

Keep this in mind when constructing over or near sewer mains, stormwater pipes and electrical cables.

Here is a video that explains the rules a little bit more.


The rules for building over or near sewers changed in November 2013. Under the new approval process, building work over or near a sewer must be assessed against Queensland Development Code Mandatory Part 1.4 (MP 1.4).

The Department of Housing and Public Works has information on MP1.4.  This is the manual we refer to when preparing a build over sewer application in Queensland.

Need Help?

We’re here to help. Would you like Cornell Engineers to assist with your Build over Sewer applications? Get a Quote.