IT’S NOT WHAT YOU SEE…
Most jobs look the same when first produced. The good tradesman is hard to tell apart from the cheap one. The surfaces are good to look at at first. This is because most concreters can lay the concrete pretty much the same, so you are happy with your investment at first.
However, it is what you don’t see that will guarantee your long term satisfaction.
When I first started concreting back in the 1970’s there were some cheap jobs done then which did not stand the test of time. You may see them today with the surface worn away, very badly cracked and sunken in places. Back then concreting was barely recognised as a trade and practices were poor despite a concerted effort by council inspectors to police the preparation.
So what were the bad practices which in a large part persist today. Let’s use driveways as an example.
- Poor preparation.
Driveways were dug out with a bobcat and then poured straight over the resultant levels. No attempt was made to compact the subgrade to ensure that the driveway did not sink in the future.
No bedding sand was used to compact the subgrade and ensure that the driveway was of equal thickness throughout.
Mesh was placed on the ground using the cheapest mesh available which was very thin. Sometimes there was no mesh at all or the contractor took it away after the driveway was inspected.
2. Poor pouring techniques.
Because chairing was a new thing, most contractors would simply hook the mesh up into the concrete. However this would result only in the mesh sinking to the ground and lying on the bottom of the finished driveway, providing no structural vale at all. This practice still persists today in many cases and leads to future cracking when the driveway is put under load. Many concreters are lazy and do not want to work hard, so they wet the concrete up to make it easier to spread. This results is the surface washing away over a very short time after pouring and revealing sand or aggregates.Also, the driveway is reduced in strength and will soon crack and deteriorate.
3. Insufficient Jointing
Engineers have produced guidelines for jointing practices. Types and distance apart are some of them. These can be ignored if they are not costed into the job and result in the job cracking in the future after laying.
4. Insufficient Curing
Curing concrete results in good durability of the finished surface and increases the compressive strength of the concrete. If ignored your driveway simply wont be as strong and will wear significantly.
Hopefully this article has helped you to take particular care that your contractor knows exactly what he is doing to produce something that is more the cosmetic. Shortcuts save the contractor money, but can cost you heaps in the future.
Cheapest is not always best, in fact it rarely is.
It’s not what you see that counts.
David Schofield