Exterior and Interior Plastering in Launceston

That sentence is about the planning scheme. It does not replace the Heritage Council's approval for works to a place on the Tasmanian Heritage Register: a registered place needs that approval whether the plaster is inside or out.

Coatings on old masonry

Heritage Tasmania's Works Guidelines say to avoid applying waterproof or water repellent coatings on masonry where there is a likelihood that these will trap moisture and prevent evaporation, causing damage. If a quote for outside work includes a coating, ask the provider what it will do to moisture in the wall.

Finishes that were there before

The same guidelines have a row on reconstructing historically significant finishes to surfaces that have been covered, damaged or degraded where the surfaces will be coated with the same treatments as previously applied. They do not say how to tell which finishes are significant. For a registered place, that is a conversation with Heritage Tasmania, and an application for replastering has to carry notes on the existing finishes.

Say in your enquiry whether the work is inside, outside or both. The local heritage page covers what the City says for a place in its local list.

Does plastering the outside of an older building need a permit?

The State Planning Office lists exterior decoration of a building within what the scheme treats as development. Whether a permit is needed for your building is for the City to say.

Does inside plastering need a planning permit?

The State Planning Office says internal buildings and works are exempt from requiring a planning permit, though you may still need a building approval.

Is a registered building treated differently inside?

Heritage Tasmania says works to a place entered on the Tasmanian Heritage Register need the Heritage Council's approval. It does not draw an inside and outside line in the sentence we read.