Spatulas and warm water are to replace jackhammers as the tools of the trade for construction and utility maintenance workers in historic parts of Dublin city.
Dublin City Council is to ban the use of power tools on original road and path surfaces and has identified more than 300 streets with antique granite kerbs, flagstones, or cobblestones needing protection.
A detailed manual for working with historic materials has been drafted that will put tight restrictions on utility companies digging up streets and could add thousands to the cost of underground repairs.
The council had been criticised by heritage organisations including An Taisce and the Dublin Civic Trust for allowing the loss of historic paving and its replacement with tarmac or Chinese granite.
Prior approval
The new rules will require any company to seek prior approval from the council for work that could affect original pavements and roads. "No historic kerb, flag or sett [cobblestone] shall be cut" and "power tools should never be used" the manual says. Stones should be cleaned using appropriate conservation methods and "chewing gum shall be removed by gently scraping off the stone using a spatula."
Workers should avoid disturbing historic paving if possible and should instead use an “alternative approach” such as tunnelling to the location from an adjacent non-historic area.
Where flagstones or cobbles have to be lifted, a detailed survey with photographs must be carried out and the stones should be numbered to ensure they are replaced in the exact location. In order to lift a stone the joints must be raked out to avoid damage to the stone.
“Raking out shall be preferably carried out by scraping and picking rather than hacking or chiselling.”
If a chisel has to be used, the council will specify the type. Any drilling, with a masonry bit only - not power tools, would require prior approval.
Stones that are removed should be stacked on pallets and not on top of each other. “Pallets shall be of softwood, with no oil-based preservatives.”
To replace cobbles they must be “soaked in water for three to 10 minutes, and then placed in position one by one and lightly tapped into place”.
Granite kerbing should be cleaned using warm water without detergent. The spray must be held at a distance of no less than 450mm from the face of the stone.
Cracked or broken flagstones should be reused where possible. Slabs with clean breaks should be fitted together in their original form. Where repairs are required, Leinster granite must be used and care should be taken to match it with the original stone.
