It has been estimated that the three phases of the construction required more than thirty million hours of labour.
... Stone
limestone
clay
About 5000 years
To build the whole of Stonehenge will obviously depend on how many people there was for the task. What we suggested was that, given a great concentration of effort, is the sarsen structures, the biggest bits of Stonehenge, could have been built within a period of three years. We suspect that probably it took longer. There is the opinion that Stonehenge was constructed in sections over a period of time that span as many as 300 to 500 years.
Stonehenge is made from sarsen and bluestones. Bluestones was regarded as magical stones and forms the inner circle of Stonehenge. The sarsen stones are the very large ones on the outside of the circle. See the link below for more information.
every thing decomposes at different rates but some materials take about 30 days
As Stonehenge was constructed long before written records were kept there is no recorded evidence of any construction problems.
A very long time, it was used to design the Pyramids and Stonehenge
30 Million Hours!!
stonehenge
As an expression of a long lost prehistoric cosmology:See the Related Link.