Who builds pillare to front of house

Hi All,
I have been asked who would build pillars at the front of a house. I think it is the blocklayer? The pillars will be supporting a porch and are circular so I assume they would need a mould and be poured concrete.
Lastbuilders

If they are circular, then they are called columns, not pillars. They can be bought precast, or made to order. They look very good in Sandstone finish . Some examples can be seen on detached houses on Hazelhatch Rd, Celbridge.