The answer to the question above is no. We do not need to receive any recognition from the HDB departments in order to paint HDB flats, be it interior or exterior. Most of the painting contractors or companies are not recognized in Singapore.
As long as we do not tear down any walls in the HDB flat, we are not required to have any license or recognition from the HDB boards.
This was asked by a customer inquiring on painting services yesterday, so I found it good to share with you all. However we are a private limited company and we are accountable to our clients and the S’pore Govt (if you know what we mean!) 🙂