Preparation

Sub grade
Sub grade is a term used for the ground level after excavation is done.  All sub grades should be excavated and checked with levelling equipment to ensure adequate fall is being given to the sub grades.

The finished sub grade should look like the desired finished levels of concrete and all sub grades should be well compacted.  A firm surface road base compaction in layers is the correct method for any additional fill required to bring new levels higher, all pipes whether they be stormwater, sewer, gas, electrical, water, irrigation, etc.  These should be buried in the sub grade where achievable and never through the concrete as concrete expands and/or contracts with temperature change in weather resulting in 2 possible outcomes.

Broken pipes, be it gas or water; you could imagine trying to locate one of these is not cheap nor is it safe.  Another implication is colour matching, imagine a repair under a pristine driveway.  ‘Now just as all concreters were not created equal neither is the material that is under your driveway’, is it rock, mud, clay, sand, shale, dirt or is it a combination of

any of these things?  Perhaps its infill which is soil that has been brought from another site to yours, if so has it been prepared properly?  If your answer is ‘no’, then how far down is it to solid ground? Have you checked for this and is it necessary to drop a couple of piers down to solid ground and tie your driveway into that? Well that depends on what the driveway is being used for and what is the expected weight to be on top of the slab, can you see where I am going with this?  There a lot of variable factors that determine the required course for action, slabs that move because of inadequate construction planning and reinforcing can become extremely expensive down the track depending on the level of structure on and around the slab which forces me to say beware the cheap quotes as knowledge is key in construction of certain slabs.

If you are having coloured concrete performed whether it is stencil, stamp, etc. all surround brick work and concrete, needs to be covered with plastic to protect everything surrounding the job.

We use a clear plastic called builder’s film.  This is tucked down behind the expansion joint and is clouted or taped up all walls to its 1meter height thus protecting the walls

from concrete splashes and more importantly the colour (oxide) that is used, it sticks to everything, no matter how careful someone says they will be prevention is better than cure.  Extra care is needed if a concrete pump is used with the placement of concrete as pumps spit and splash, so all drains and pits should all be tapped for protection.

We use grey tape as it protects the best and comes of easy revealing the new state of drain as it should be, never use masking tapes it soaks up water and rips off in little pieces. You will end up using a paint scrapper to get it off damaging the grate surface and leaving scratches now I know I wouldn’t be happy with that if I were the paying customer.  Your contractor should also apply the first coat of sealer to the job on the same day of concreting as there is no better time to protect your job.  We do this so we can sleep well at night knowing that our

efforts are not going to be spoilt by unexpected weather even if it’s not forecast it does happen. Nowthis cannot always be achieved, it’s a summer thing as you need to be able to walk over the new concrete, so it needs to be hard enough and not all finishes applied to concrete allow you to be able to walk over it the same day, no matter what time of the year it is.