How to demolish reinforced concrete staircase / concrete stairs? How to remove concrete staircase from the house with Dynacem? How to demolish a staircase in the basement with Dynacem?

It is necessary to provide support for the structure and take into account that demolition may cause loss of stability and collapse of all or part of the stairs.
It is best to drill vertical holes.
Recommended hole diameter 36-40 mm. Smaller diameters can also work, but with worser results and in the longer time.
Drilling depth = 0,9 x H (the deeper the hole, the greater the destruction).
Always keep d < S < 40 cm (to obtain both longitudinal and transverse cracks).
Greater S values produce bigger cracked concrete pieces. Note that the chunks may be too heavy for manual transport.
Smaller S values provide smaller concrete chunks.

The principle is demonstrated by the sketch below:

Filling holes with Dynacem mixture starts from the free side edge of the stairs.
It is best to fill every other hole on each stair step on the first day and fill the remaining empty holes the day after (filling option A). Remove cracked concrete on the entire area 2-4 days after the last holes were filled.

Holes filling sequence options:

Alternatively, having more time, it is possible to try to demolish the stairs without the support. It is only possible when the stairs have left or right side edge free.
On the first day, just the first holes (from the free side edge of the stairs) are filled at all steps. Then one hole nearest to free edge is filled at each step every 24 hours (filling option B). Remove cracked concrete beginning from the free side edge.

You will find photo galleries showing the demolition of various stairs here: 1, 2, 3.

Here you can see TikTok videos of reinforced concrete stairs test demolition performed in a bricklayers training center: link.