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Pouring concrete slab in the right way is
Pouring concrete requires adequate planning, preparation, delivering materials, and following suitable procedures to carry out the work properly and achieve the expected results. The concrete slab for a shed would not conform with requirements of the project unless necessary measures such as curing
At this stage, required materials and necessary tools are prepared and delivered to construction site.
2. Prepare Construction Site
Specify the size of the slab and remove any bush, tree, rocks or obstructions from the construction site. It is advised to clear an area greater than that of the slab to make pouring operation easier.
3. Mark Slab Base Location
4. Excavation for Shed Foundation
The area that needs to be excavated for the foundation is slightly larger than the area of the shed to account for formwork accommodation. The depth of excavation, which is measured from string line, is based on the thickness of the slab, extension of the slab above ground, thickness of gravel layer at bottom of the
If the gravel thickness is 15cm, slab thickness is 10cm, and slab extension above the ground is designed to be 10cm, then the depth of excavation would be 20cm. Levelness of the excavation area shall be check during the digging work. Added to that, loose materials are required to be removed.
5. Fix and Level Formwork
After the completion of excavation work, a formwork is fixed and levelled, and its diagonal shall be checked. It needs to be strong to make sure that the concrete pressure is contained. No gaps in formwork are acceptable since it allows concrete to escape. Frequently, wood formwork is used.
6. Place and Compact Gravel Layer
Gravel layer can be placed after the formwork is fixed and levelled. In order to achieve good compaction degree, it is recommended to place and compact gravel in three layers.
Suitable compaction machine such as vibrating plate can be used to apply compaction effort. Gravel layer levelness shall be examined, in addition to its thickness which can be checked by measuring from the top of the form to the top surface of
Gravel layer thickness around the perimeter of the slab is decreased in order to have greater concrete thickness. The width of the thickened concrete around the perimeter of the slab would be 30cm.
7. Install Rebar
Steel bars or steel mesh are installed to overcome the brittleness of concrete. S
An alternative to the grid or mesh is using concrete with synthetic
Finally, the thickened concrete around the perimeter of the slab shall be reinforced with two additional rebars preferably No.13 bar size or greater.
8. Pour and Compact Concrete
After reinforcement placement and preparation of necessary tools, concrete pouring process can be carried out.
The location of openings and doors shall be specified on the outside of the formwork. The level and diagonal of the forms shall be checked.
It is advised to slightly moisten steel bars before concreting to make sure that concrete encircles the bar easily and improves
9. Level and Finish Concrete
The concrete should be slightly above the forms. Use a shovel or rake to spread the concrete around and move it into low areas.
Place anchor bolts into concrete during screeding and smoothen the area around bolts. Smoothen the concrete surface after
After the smoothening is done, finishing work begins. Concrete finishes should be applied when the top of the concrete is semi-dry. After slab levelling, the water rises to the top of
The time it takes for this to happen varies on the temperature, and how much sunlight is exposed to the concrete. If concrete is poured in hot weather condition, then finishing shall be done quickly. However, if the slab is constructed in cold weather, it might take a while till concrete is ready for finishing work.
Edge the concrete where it meets the forms because it reduces the chance of chipping and makes it easier to lay the bottom plate flat.
10. Concrete Curing
Based on the weather condition, select suitable curing regime to make sure that concrete achieves the designated strength. Commonly, the curing process begins 24 hours after the pouring of concrete.