By Heather Bauchop,
The proximity of good building stone and the scarcity of timber has created Oamaru’s architectural identity – Whitestone City. Limestone also provided the mortar for these same buildings – smaller pieces of stone were burnt in kilns to produce quicklime. Quicklime was mixed with local sands and slaked (combined with water to produce calcium hydroxide) to make mortar.
Here are some things to avoid:
- Don’t change the pattern of the masonry – repairs should match the original work
- Don’t sandblast or use high pressure water jets – either use chemical stripper or low pressure water
- Don’t replace timber floors with poured concrete – this forces the dampness into the walls
- Don’t use cement when repairing lime mortars, plasters and renders
- Don’t seal walls with water-repellant coatings or use acrylic or other impermeable paints