Lime mortar specialist Michael Power and stone mason John Edstein have combined their skills to give the memorial clock a major facelift over the next few weeks.

The restoration will include a thorough cleaning of the sandstone, which has discoloured over time, removal of the concrete pointing (mortar) and its replacement with traditional lime mortar.

Michael said the removal of the concrete pointing is crucial to the process, as the effect of concrete against stone erodes the stone over time.

"We're taking out the concrete pointing to a depth as far as we can (at least 25 mm) and replacing it with a traditional lime mortar.

"Lime is a beautiful material to work with. It's became a bit of a lost art really, but it's part of my culture. In my home town in Ireland you can see the use of lime in all the old buildings," Michael said.

Lime mortar is porous, so any water absorbed by the stone is able to evaporate through the lime mortar, thus protecting the integrity of the stone.

Concrete on the other hand lets water in, but doesn't let it out again - trapping moisture in the stone. When this happens the stone starts to fret and delaminate - a process where the surface begins to flake off - which if left unchecked, can ultimately result in the sandstone returning to sand.

Like many historical buildings, the memorial clock, had its traditional lime mortar replaced by concrete in the 1960s.

Heritage specialist, Lillian Cullen said the use of concrete was common during this time.

"During the 1960s, many historic stone buildings were re-laid in cement. It was cheap and strong and therefore considered an ideal building material, but now we know that stone is not compatible with cement," Lillian said.

As the concrete mortar is being removed, the sandstone is being thoroughly cleaned with a special solution developed over many years by local stone craftsman, John Edstein. It was John Edstein's grandfather who oversaw the building of the memorial clock, after World War I, in its original location at the intersection of Victoria and Manning Streets.

"The sandstone came from a Gosford quarry and arrived in blocks. The blocks were cut, shaped and laid with limestone pointing. The colour of the sandstone was white, but has greyed over time," John said.

John is one of the few people in Australia with the knowledge to restore the lead lettering embedded within the marble panels at the base of the clock.

"Refurbishing the marble panels requires a thorough cleaning first of all.

"Each lead letter must be cleaned of the residue that's built up behind it. Over time moisture becomes trapped behind the letters, expands and contracts, which gradually forces the letters out from the marble.

"Some letters will have to be totally replaced, others cleaned, hammered and resurfaced," John said.

The refurbishment will also include the addition of larger vents at the base to allow more airflow and reduce the build up of moisture within the monument.

Greater Taree City Council staff, across several departments, have come together to oversee the refurbishment and they say the community interest, and support, has been incredible.

"The memorial clock is a significant historical feature of the town and we're pleased to have the combined skills of Michael and John for the project," Lillian said.

"Obviously the restoration isn't going to bring it back to its original condition, but we're sure the community will be pleased with the results."