Planning and Building Regulations applications are dealt with entirely separately. So gaining planning permission it is not a guarantee that you will get approval under Building Regulations (or vice versa). In fact, the information required to meet Building Regs has little in common with that needed by the planners, and is assessed by a different method. There’s a large element of subjectivity at play when it comes to getting planning, whereas obtaining Building Regulations approval is, in many ways, simpler and more predictable. On the whole, if you follow the edicts set out in the relevant approved documents and technical standards, your project will be approved; and if you don’t, it probably won’t.
Designing to meet the Building Regs