It actually took him less than four years, as he was absent for long periods and had to be forced back to continue work.
What he did in this period was to fill the entire ceiling with murals, about 520 sq metres = 5600 sq ft.
It took Michelangelo 4 years to paint the ceiling of the Sistine Chapel. He painted it between 1508 and 1512. Then it took him 6 years to paint the Last Judgement, which is a fresco on the wall of the altar of the Sistine Chapel. Painted between 1535-1541.
Michelangelo made the piantings in the chapel called Sistine Chapel
In order to paint the ceiling of the Sistine Chapel Michelangelo spent years lying on his back on scaffolding.
6 years
It took Michelangelo 4 years to paint the whole ceiling of the Sistine Chapel.from 1508 to 1512.
The Sistine Chapel (ceiling + Last Judgment).
1508 to 1512 it took 4 years
It took him four years, birthdays or no birthdays.
5 years
Michelangelo did.
The Sistine Chapel, designed by Michelangelo, took almost eleven years to build (1473 to 1484) under the supervision of Giovannino de Dolci for Pope Sixtus IV. Find out more about the Sistine Chapel at http://vaticanart.net/painting-of-the-sistine-ceiling
It seems he did. The commission was from 1506. But what MIchelangelo did before starting work in 1508 we do not know.