Well, in many occasions it is a uncountable word.For example,when it means as
(1) the job that a person does especially in order to earn money: He started work as a security guard.
(2) the duties that you have and the activities that you do as part of your job: The accountant described his work to the sales staff.
(3) tasks that need to be done: Taking care of a baby is hard work.
(4) materials needed or used for doing work, especially books, papers, etc: His work was spread all over the floor.
(5) the place where you do your job: I have to leave work early today.
(7) a thing or things that are produced as a result of work: Is this all your own work
(8) the result of an action; what is done by somebody:The damage is clearly the work of vandals.
However, when it means as follows, work can be used as a countable word.
(1) a book, piece of music, painting, etc: Beethoven's piano works
(2) (often in compounds) They expanded the shipyards and started engineering works.
(3) (often in compounds) Raw materials were carried to the works by barge./ a brickworks