Pouring concrete sounds like a simple task, but the truth is it’s a challenging job – not least because it’s rare for any two concrete pours to be the same. When you take into consideration the size of each project, and the varying aspects including dimensions, colour, finish and complexity, it’s important to have some understanding of the concrete pouring process. What happens before a concrete pour? What happens during? And what happens once the concrete has been poured in place?
In order to answer those questions, we’ve put together this handy step-by-step guide to pouring concrete, so that you can get the very best out of this uniquely versatile material – whatever the project.
1. Preparing The Site
It doesn’t take a genius to figure out that you can’t just start pouring concrete without first preparing your site.
Expansive soils and frost can hinder your chances of a good concrete pour, so you need to start with a clean slate, so to speak. If you’re undergoing a large concrete pour, it makes sense to speed up the site preparation process by using earth moving equipment, whereas smaller projects can be prepped for by simply using hand tools to remove trees, bushes, old concrete and rocks.
If you’re left with soil that is very compact and stable, it’s on to step 2….if not, you need to first add and compact a sub base of fill gravel first.
2. Forming
Once your sub base is all prepared, it’s time to set your forms for the concrete pour. Forms
needed for residential projects can be set using wood forms that are attached to metal or wooden stakes with screws or nails that allow for easy removal once the concrete pour has cured.
Don’t be tempted to use forms that are in anything other than good condition! They need to be set so that they give the correct slope for drainage, and make sure that flush corners are formed in the areas where they meet each other or any other structures.
3. The Mixing Process
If you’re embarking on a smaller project, you’re likely to be using bagged concrete, which you’ll need to mix with water as per the packet instructions. You can use a wheelbarrow and shovel for small amounts, but a concrete mixer is undoubtedly going to make mixing much easier, and these are readily available for hire from a number of outlets.
For larger jobs, your concrete might arrive in a ready-mix truck with a drum on the back that will spin to stop the concrete from settling and solidifying.
4. Placing The Concrete
Once the concrete is mixed your next step is placement. The wet concrete needs to be poured into your forms right to the top edge. During this part of the concrete pouring process you can use ‘come alongs’, a specialised concrete rake, to move the concrete and prevent air pockets. A normal rake or shovel will do the job as well!
5. Screeding
Screeding compacts and consolidates the concrete and is done using a large metal or wooden board. A float is then used to even out and compact the concrete further and create a smooth finish. For edges and detail work you can use small hand-help floats, and you can use large bull floats for the larger areas.
6. Troweling
Perhaps the area you are concreting is going to be finished with a rough broom, in which case you won’t need to worry about additional finishing. However, for a smooth, uniform finish you’ll need to use a steel trowel. Once the concrete has rested sufficiently enough that the surface has begun to firm up, you can steel trowel the surface by using knee boards and concentrating on small areas at a time. An alternative is to use ‘fresnos – long poles with a trowel attached.
7. Final Finishing
You’re nearly there! Once you’ve completed trowelling it’s time to apply the final finish. The most basic type of finish is known as a broom finish – and is exactly what it sounds like; a special broom is pulled across the surface of the concrete and leaves a rough and textured finish.
Other types of finish include stamped, often called textured or imprinted concrete (where the concrete is made to look like natural stone such as slate or flagstone, for example), stencilled finish, or smooth trowel finish.
8. Curing
The final step in the concrete pouring process is to let the concrete rest and go hard – known as curing. This step is the most lengthy one, with curing lasting around 28 days, with the first 48 hours being the most important.
You can apply a chemical curing compound at this stage to ensure that the concrete cures slowly and evenly. This is important when it comes to reducing cracks and surface discoloration. 3 or 4 days after the placement of your concrete you can start with light foot traffic…and after 5-7 days your concrete should be cured enough that you can drive and park on it.
