Local planning authority usually determines whether a conversion will be classified as a new build or not. Even if most of the existing barn remains, it may be classified as a re-build. Re-builds typically require planning permission while a barn conversion does not. While it may be tempting to assume your project is not a new build, it may cost you in the long run. If you are planning on converting a barn, you should contact the local planning authority first. If you are required to get any permits or permission, you can factor these expenses into the project cost. Financing can be used to cover these expenses.