In this article, we will talk about concrete work or “beton” as we commonly call it.
Let’s move on to one of the most basic tasks in constructing a house. Concrete work is very important to be done correctly and responsibly because it largely ensures the structural stability of the construction, and therefore our safety.
Second stage – Concrete work
For the concrete work to be carried out, a crew is needed to build the forms and place the rebar. This crew is called the formwork crew but in construction jargon, they are known as formworkers and rebar workers. All these tasks are supervised by the project’s supervising engineer, who ensures that everything is done according to the study.
What to pay attention to at this stage
1. Where will the building be located?
Before formwork begins and after excavations, a layer of concrete called “clean concrete” is laid at the bottom of the excavation. This is done to provide a clean surface to start the project and to mark the position of the building, with the help of a surveyor. The position of the building is a very important task as it will be checked at a later stage and if done incorrectly, it is very costly to correct.
Image 1: Marking on clean concrete
2. How do I arrange a price with this crew?
The price is usually determined per cubic meter of concrete. The crew will study the structural plans and give you the price per cubic meter, which usually involves the work called “fatura.” To this price, you need to add the cost of the concrete, the cost of the reinforcement, the cost of placing the reinforcement, the concrete pump, and various other extra charges such as stairs, beveled corners, grooves, exposed concrete, etc. The costing of this work is quite complex and if you do not have technical knowledge, it is likely that you will not calculate it correctly.
3. How much rebar should I put in? How much concrete should I pour?
All concrete works are described in detail in the structural plans and have been calculated for your building. These plans are followed meticulously and contain all the details for both the reinforcement (rebar) and the thickness of the concrete to be placed.
Image2 : Building rebar
4. Should I add more rebar to make the building stronger?
Structural studies, especially after the 1999 Athens earthquake, have become particularly strict and very safety-oriented, so it is not required to intervene further and add extra reinforcement. In any case, this should be discussed with the supervising engineer because there are instances where additional reinforcement could cause harm instead of good.
Image 3 : Slab reinforcement
5. How can I be sure about the quality of the concrete delivered?
Visually, it is certainly not possible to tell if the concrete is good or not. The procedure you need to follow is to take samples. What are samples? Samples are small metal containers (about 15cm x 15cm x 15cm) that are filled with the concrete being poured on the construction site from each mixer truck that arrives. These are then sent to specialized companies that, using the method of breaking, provide you with the results for the concrete quality.
Image 4 : Concrete samples
6. Should I consider other tasks that will be carried out simultaneously with the concrete work?
Of course! The construction is starting, so gradually all specialties will begin to take part. The first to arrive are the electricians and the plumbers. The electricians will construct the foundation grounding, which, as the name suggests, is done at the foundations and they may also come during other concrete works to place the boxes for balcony spotlights. The plumbers will lay any pipes or shafts needed in the basement floor.
The insulation technician should also come to insulate the basement perimeter. Therefore, it is important before starting the construction to have finalized the crews you will work with.
Image 5 : Foundation grounding
7. What is the best time of year to start concrete work?
All seasons are good. Naturally, spring and autumn, which have milder weather, significantly help the work. Concrete work is not done during heatwaves (temperature above 35°C) or in periods of cold (<3°C). In heatwaves, the concrete can dry very quickly on the surface and in cold, the water inside can freeze. Both of these phenomena will reduce the strength of the concrete.
Special attention should be given during the concrete work of the basement in case of heavy rainfalls. Soil carried by water might cover the building’s reinforcement, and the crew will need to clean it thoroughly before proceeding with the concrete work.
8. Is there anything else I should be careful about?
One thing that will make life easier for many crews and will not burden the building with potential digs is the provision for routing in the concrete work. What does this practically mean? Consider that a downspout may start from the roof and pass through all the slabs. In this case, either the plumber will open these holes afterward by drilling through all the slabs, or you will have pre-planned and placed styrofoam at the required points, so the holes are easily opened. This, of course, presupposes quite good planning to leave the necessary points.
Image 6: Provision for routing
The next stage is masonry. Read the next Blog here
The above is not technical writing and aims to simply inform the reader. The MECHA Engineering team has experienced engineers who will certainly and scientifically guide you in your technical project needs.