The fire broke out at a semi-detached house in St Denys Close at around 6pm yesterday (September 10).
The man was treated at the scene by London Ambulance Service crews before being taken to hospital.
Four fire engines and around 25 firefighters were called to tackle the blaze, which damaged most of the house.
The first and second floors on one side of the property partially collapsed.
A 25-metre cordon was set up as a precaution and 20 people were evacuated from neighbouring homes.
London Fire Brigade said it received the first of five calls at 6.02pm.
Crews from Purley, Wallington, Croydon and Woodside fire stations were sent to the scene, with the fire under control by 8.42pm.
The cause of the fire is under investigation.
