If you are working to a budget then we can give you costs per square meter as a good starting point however, other factors can affect the costs such as type of foundations, quality of materials such as roof tiles can vary along with the quality of interior fixtures and finishes. Once the technical drawings or Building Regulation drawings are available, which dictate how the project should be built we can then provide a more accurate quotation. There are professional fees to factor in and It is a good idea to allow 10 per cent extra for unexpected additional costs.