Before building a house, you will need planning permission from the local planning authority. Often, plots are sold with planning permission in place, but this is not always the case. Even if a plot already has planning permission, you may wish to alter it to get exactly what you want. This is where a planning consultant can help.
The process can be costly and dogmatic, so it can save you time and money if you find out whether you have a realistic chance of achieving what you want before submitting a planning application. A good planning consultant will also be able to advise you on how to achieve your desired outcome.