Construction of concrete stairs includes steps such as designing, preparing the foundation, building formwork, placement of reinforcement steel bars, concreting, finishing, and curing. Construction of concrete stairs is a difficult task that requires an engineer to study all the aspects and design it and skilled labor to construct it. In this article, we explain to you the detailed method of how to construct concrete stairs from start to end.

1. Designing of Concrete Stairs

Designing stairs requires a thorough knowledge of design aspects and site study. The factors that influence the design of stairs are the height of the floor, the width of the stairs, risers depth, tread width, the thickness of the stairs, angle of the stairs, the load applied on the stairs, and many other aspects which require a qualified engineer to design the perfect stairs. The standard dimensions for stairs components are

Component

Standard Dimension

Thread

9 - 9.25 Inch

Riser

7.5 – 8.25 Inch

Width

3 Feet

Flight Angle

30 - 45 Degree

2. Foundation and Support for Concrete Stairs

The foundation on which the rest of the concrete stairs is to be properly constructed so that loads of the stairs are transferred in to ground successfully and to resist the movement of stairs. If the plinth beam of the building is present at the start of the stairs, then the reinforcement steels bars can be connected to them which will transfer the loads. If no plinth beam is found, then a small concrete foundation or size stone masonry is constructed. To support the stairs at the top which restricts the movement of stairs is usually done to the roof beam or slab.

3. Building the Form-work for Concrete Stairs

The most important step when building concrete stairs is to use proper formwork. The angle of flight, dimensions of tread, and riser are to be properly checked. Usually while constructing stairs attached to the wall, the line of flight, thread, and risers are marked on the wall for proper fixing of shuttering or formwork.

The boards must be at least 2” thick, to support the weight of the concrete. The whole structure of the form must be supported by 4×4 posts. The wooden boards are used to create the steps and are fastened with several screws to the lateral structure of the formwork.

4. Steel Reinforcement for Concrete Stairs

The concrete steps are to be reinforced with steel bars so as it carries the loads coming upon the stairs and transfer them to the ground. The number of steel bars and size of the bars is to be calculated by structural engineers depending upon the loads coming on the stairs.

These steel reinforcement bars are placed in the formwork with a minimum of 25 mm spacing and is tied together.

5. Pouring of Concrete for Concrete Stairs

Pouring of concrete into the formworks is started from the below part to above. The concrete mix plays an important role in the strength and durability of stairs. The standard mix used for stairs is 3 parts cement, 2 parts sand, 4 parts gravel, and water. It is recommended to use a concrete vibrator while pouring the concrete to completely fill the gaps of the stairs and to avoid the honeycomb formation. This work is to be carried out with great care and patience, as any sudden movements can disturb the alignment of the formworks or even collapse the formwork. It is always recommended to pour the concrete ceiling and stairs on the same day, as to create a strong bond between these components.

6. Removal of Formwork 

The stairs require at least 21 days to dry out completely, so the removal of formwork is to do only after 21days. In these 21 days, proper curing is to be done to prevents the cracks in stairs due to thermal expansion.

After 21 days, the formwork is removed by using a hammer and a crowbar. Work with patience, to avoid damaging the concrete or the edges of the stairs.

7. Finishing of Concrete Stairs

Once the formwork is removed, the stairs can be finished in many ways as per the requirement of the use. It can just be finished using trowel or float to give concrete finish, cement tiles, granite can be installed for better appearance. Even carpet or wood can also be used to finish the stairs.

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