Lime in Ireland – Techniques

Hot lime mortars

a strong mixture

Hot lime mortars are quicklime based mortars, mixed and applied hot. A mixture of quicklime and sand is sprayed with water: the quicklime, wet, develops heat. The mixture is normally left to rest overnight and can be immediately used (still lukewarm) or stored more than one month and used later. Hot lime mortars have a strong moisture resistance andh strengthness. With the same principle is possible to produce lime-based paints. Widely used in north european countries, they were used also by romans, although not everywhere. It is possible, of course, add pozzolanic aggregates or other ingredients to the mixture.

Lime washing and shelter coat

Painting with lime

Wall painting using lime putty. The lime is simply mixed with water to obtain a wall paint. It can be white o colored with pigments. When thin sand is added to the lime putty , the paint is called Shelter Coat. Shelter coat is usally applied to exposed facades.

Pointing and wigging

For exposed facades

Pointing is the technique of filling the space between stones or bricks with lime mortars.
Because external walls are exposed to (bad) weather, often the external pointings disappears; during the last century most of building ware repointed with cement, diminishing the breathability. In addition the pointing was ofter incorrect, offering to water the possibility to remains into the building, instead of go away. The pointing must create a continuity between stones/bricks, with no holes or irregularities that allow water to settle. The pointing must be breathable (so made by lime based mortar) otherwise the moisture tend to evaporathe through stones/bricks and not through pointing, beginning wall’s decay.

Urban building (in Dublin for example) are often with bricks on facade. A specific stile of pointing bricks facade is called “Wigging”.

Lath and plaster

a smart techiniques for interiors

Lath and plaster is a building process used to finish mainly interior dividing walls and ceilings. It consists of narrow strips of wood (laths) which are nailed horizontally across the wall studs or ceiling joists and then coated in lime plaster. The mixture is made woth lime, sand, water and hair (horse’s or goat’s). The space between two laths permit

Wet Dash

a rough finishing

Wet Dash, also known aoutside Ireland as rough cast or harling, is a rough finishing render where gravel is used together with lime and sand. Is a common render in vernacular houses and helps the water go away from the walls.