All sorts of jobs around the home and garden require a little concrete here and there. The trouble is that you might be put off using it because it is a material that professional builders use. Although precast concrete and reinforced concrete need a professional eye, you will be able to carry out most simple concreting jobs yourself with a little practice. Read on to discover how to….
1. Prep. In order to pour concrete or to shovel it into position, you need a flat area of ground to work on. Therefore, remove things like plants, old concrete and stones from the ground. You need to see raw earth before you can start making things like terraces or foundation footings.
2. Sub-base. Once you have removed turf, shrubs and so on, you’ll need to add a subbase on which the concrete will sit. Your subbase can be made of something as simple as stones and pebbles which you spread over the area using a rake. It will help to stabilise the concrete and offer it support.
3. Formwork. Essentially, this means making a temporary structure so that the concrete stays in the right place without spreading over to areas you don’t want it to be. Think of it as a picture frame laid flat on the ground into which you will pour your concrete.
4. Rebar. Concrete is tough but it can be brittle if you apply forces on it where it has no residual strength. To make concrete strong enough to stand on or drive over, add a rebar. Wire mesh makes for a good rebar that you should simply lay over your subbase. If the area you are concreting is small or if it won’t take heavy loads, then you don’t need to worry about this sort of reinforcement.
5. Mix! Cement, sand and coarse aggregate, or gravel, should be mixed together to form the concrete. Use a ratio of one-part cement to two parts of sand to four parts of aggregate. Work the material together using a shovel or hand trowel and then add water. The more water you have, the easier the concrete is to handle and pour into place. The drier you keep it, the stronger it will be. For large projects, hire a cement mixer.
6. Pour. Whereas professionals will pump their concrete mix into place, you can simply wheelbarrow it and tip it out. Shovel it by hand into all corners of the formwork and even it out using the back of a spade. Imagine your concrete pour is like a cake in a tin ready for baking – you want an even amount of material at every point.
7. Screed. Screeding involves flattening out the concrete at the surface. Use a plank of wood and jiggle it about on its side to work the wet material back-and-forth. This will ensure that no peaks or troughs appear. If you need to reach a long way from one side of the pour to another, then you may need to enlist the help of a friend so you can do this. Be gentle when screeding to get a really professional-looking appearance to the surface of your concrete.
8. Float. Floating is finishing to the surface. Do this as soon as you can after you have screeded it. Ideally, you will have a floating device which will allow you to compress the concrete easily. A bull float, for example, is used by moving it away from you while keeping the side close to you slightly elevated. Once completed, make some control grooves every couple of metres. These are simply scratched into the unset concrete to ensure it doesn’t crack in hot weather.
9. Finish. If you want a high-grip concrete surface, for example for a trackway, then use a broom over the surface of the semi-set concrete. The bristles will create a roughed up edge that adds greater traction to the surface. Don’t do this too early, or you will find that the bristles clog up and the finish is not very good looking.
10. Cure. The final step is to cure and seal the concrete to make it long-lasting. Most concrete pours need a 4 week period to cure properly although you will find that it doesn’t take quite as long in the summer months. Once cured, you can cover your pour with a concrete sealant which will help it to resist crack from forming and to prevent unattractive discolouration.
With your concrete and reinforcement work complete, you can stand back and admire your work. On the other hand, if you want help, then remember that we do concreting jobs. Give Brian a call on 01664 900044 for a free quotation.