According to an article on eHow, a power trowel should be used after the concrete has been poured, screeded and treated with a bullfloat.
Construction engineers were then told to press their fingers slightly into the concrete before they start deploying their concrete finishing tools.
The eHow article said that if they feel a little resistance, they should "hurry up and wait".
However, builders were advised that if they feel a firmness underneath, that would be the ideal time to start using a power trowel.
The article added that stepping on the concrete could be another way of seeing if it is ready, but it acknowledged that this option could potentially be risky.
Construction professionals could find the 36" Allen Concrete Power Trowel a good product to consider, as it offers a wide range of features, including cast iron spiders, pressure plates and a long life expectancy.