Monday, 12 April 2010

A short glossary from the information sheets

See earlier posts for the information sheets.

Ashlar; Stone that is dressed with sharp square arisses (corners).
Bed/bedding; Line of mortar between courses.
Brick trowel; Large diamond shaped trowel used for placing mortar (not pointing).
Bucket trowel; Medium sized trowel, slightly tapered sides, flat end. For working out of a bucket. Good general purpose trowel.
Burning; Heating limestone to remove carbon dioxide and produce lump lime.
Carbonation; The process of absorbing carbon dioxide (in a mortar) that causes calcium hydroxide to revert to calcium carbonate.
Coarse stuff; Lime with sharp sand.
Course; A line of bedded building material (brick or stone).
Fat lime; A matured slaked lime.
Fine stuff; Lime with soft sand.
Finger trowel; Thin trowel for pointing. Width varies from 6- 24mm in 6mm increments. Also known as a tuck pointer or Frenchman.
Float; Rectangular trowel, usually metal, and used for floating plaster onto wall.
Free lime; Any uncarbonated lime (calcium hydroxide) within a set mortar.
Gauged mortar; Lime mortar with pozzolana added.
Haired mortar; Lime mortar with hair for use on laths.
Hot lime; Lump lime slaked with sand and used immediately.
Hydrated lime; Lump lime that has been partially slaked, dried, ground and bagged. Used as a plasticiser in cement mortar.
Hydraulic lime; Lime that has naturally occurring pozzolana.
Hydraulic set; The ability to set without carbon dioxide.
Lime cycle; Limestone (calcium carbonate)+heat→Lumplime (calcium oxide)+water→Lime putty (calcium hydroxide)+carbon dioxide→Limestone.
Lime mortar; A mix of aggregate and lime.
Lime putty; Slaked lumplime (calcium hydroxide).
Lumplime; Burnt limestone (calcium oxide). Also known as quick lime.
NHL; Natural Hydraulic Lime.
OPC; Ordinary Portland Cement.
Plasterers small tool; Double ended tool with leaf shape trowel at one end and rectangular trowel at other. Useful for pointing very fine joints.
Pointing trowel; A small diamond shaped trowel, best with slightly curved edges.
Pozzolana; Any material that will impart an hydraulic set in a lime mortar. Originally a fine volcanic ash from Pozzuoli near Vesuvius. Can be almost any burnt material but most commonly clay.
Putty joint; A thin bedding joint in ashlar stone or brick.
Sharp sand; Sand with broken particles.
Soft sand; Sand with rounded particles.