Equipment and plant is what you mean.
..concrete mixers and hoists are not heavy..unless we are talking of mobile and or tower cranes, beasts such as concrete pumps mounted on trucks or tracked chassis, multi - purpose bucket excavators...among others of large volume outputs.
Anyway if you are targeting low and medium scale contractors..way to go man.
It is a good business as long as you network with construction engineer, foremen and ma fundi wa mtaa. These are the guys who will link you up to a deal. I recently hired someone to do that work at cost of 20k for a shutter. His team consisted of foreman and watu wa mkono kama 7. Do the calculation of the labour + transport cost to arrive at expected gross margin profit and decide if it is kind of business you can do.