Do I need approval to carry out repairs to my house?

No- if the repairs are small and you are replacing like for like. This includes things like fixing a flat roof felt, repainting, or repairing a small section of brickwork.

Yes- if the repair involves removing and rebuilding a large part of a wall, or supporting a wall that carries weight. For re-roofing, you need approval if the new tiles or roofing material are heavier than the old ones or cover more than half of the roof.