Cement, Render and Paint on Old Walls in Adelaide

What cement, render and paint on old walls in Adelaide actually involves

On mortar, the 2008 joint heritage guide says not to use hard cement mortar to repoint failed lime mortar joints, because that will drive the damp further up the wall and may also damage the bricks. The Norwood Payneham & St Peters fact sheet puts it from the other side: older stone or brick walls should not be pointed with strong impervious Portland cement mortar, which could inhibit breathing.

The base of the wall

The same fact sheet says masonry walls should not be rendered at the base with a strong impervious Portland cement mortar plinth to keep damp out, and gives the reason: this only serves to trap moisture in the wall.

Paint

The fact sheet says old masonry walls should not be painted, as this can trap the moisture and force it inside. It is a council's guidance for heritage buildings in its own area, and the guide's dos and don'ts are guidance rather than law, so neither stops an owner doing anything. They do say what a provider should be able to explain: why a coating or mortar suits this wall.

Ask the provider what mortar, render and coating the repair will use and why, and what the wall will do with moisture afterwards. The drainage page covers what the guide says to do before any of it.

Cement, Render and Paint on Old Walls in Adelaide — common questions

Can I repoint a damp wall with cement?

The guide says not to use hard cement mortar to repoint failed lime mortar joints: it drives the damp further up the wall and may damage the bricks.

Can the base of the wall be rendered to keep damp out?

The council fact sheet says not, with a strong impervious Portland cement plinth: it only serves to trap moisture in the wall.

Should an old brick wall be painted?

The fact sheet says old masonry walls should not be painted, as paint can trap the moisture and force it inside.