Build costs will be heavily influenced by the level of involvement that you will have in the project
Using a main contractor requires the least amount of involvement in the project from you.
Building using a main contractor or package supplier up to the weathertight stage with subcontractors completing the work with materials you have bought direct from the suppliers.
Hiring trades people direct and a small amount of DIY using materials you have bought direct from the suppliers.
Carrying out about one third of the work yourself, with trades people helping with the rest of the build with material you have bought direct from the supplier.
Your budget will dictate the size of your house, so bear this in mind at the designing stage. If you want the maximum space for your money, opt to build a simple box-shape house. It needn’t look or be cheap, but it’s the easiest and most cost effective form of construction.