If you've found a site which you think is ideal for your needs, it's worth having a second look. Even if it has outline planning consent, it may not be as suitable as first thought.

How easy is the access?
A long access road to the house position can be very costly. A level access of a short distance saves money. The story of the family, who built a mile-long road to the site of their dream home only to be able to afford a caravan, is not apocryphal.

What are the ground conditions like?
Building on a bog is not impossible, just inadvisable due to the expense in making the ground structurally secure. Likewise, hard rock may have to be blasted or broken which again can have a financial impact.

Can the house be easily serviced?
Lack of a water main may mean that you look at a borehole solution or taking water from a spring. But will this water meet safety standards? A distant electrical supply can mean incurring more unforeseen expense.

What will the sewerage arrangements be?
Can you connect to a mains sewerage system or will a private septic tank or treatment plant be required?

The advice?
Do your research and/or commission a professional to do a feasibility study, before you take the plunge.