Typically it takes about two years to build a home, from finding the site to moving in.
In most cases just over half this time is spent securing planning and other building permissions and lining up suitable contractors.
Then about six to nine months is spent onsite constructing the house.
Timber frames and structural insulated panel systems are praised for erecting a weatherproof shell faster than brick and block, but they generally take longer to arrive on site. Timberframe suppliers normally require a substantial deposit in advance.
A simple house on a flat site with a good crew, an accurate budget and reasonable weather, can be completed within six months. As you add in complexities such as a steep site or bad weather then timescales lengthen.