GLOSSARY
Glossary
A
Sand, crushed stone or other material such as broken shells, brick, chalk, earth or porous particulates consisting of a large part of a mortar etc. It provides bulk, reduces shrinkage and assists setting. It can also influence mortar colour.
There will be archaeological interest in a heritage asset if it holds, or potentially may hold, evidence of past human activity worthy of expert investigation at some point. Heritage assets with archaeological interest are the primary source of evidence about the substance and evolution of places, and of the people and cultures that made them (as defined in the National Planning Policy Framework 2012).
A sharp edge such as on a brick, stone or corner of a door or window reveal.
A direction which withdraws automatic planning permission granted by the General Permitted Development Order. This is often applied as an extra level of protection within conservation areas.
Finely dressed stone laid in regular courses with thin joints.
B
A building material used up to c1890, especially in coastal areas of East Sussex. Employed for whole walls constructed with shuttering or as an infilling between two skins of flint or brick. Typically lime, sand and pea beach shingle were used to form a mortar to which flints and any other materials to hand were added, eg pieces of brick, pipe or wood.
A wide sloping board set edge uppermost along the top of a gable. It may be carved or ornamented.
A small projecting corner turret or embattled parapet at the top of a tower, gatehouse or curtain wall. Miniature bartizans are integrated into the design of many rainwater heads.
A clay mineral that can assist the flow of a grout.
C
An H-section lead or copper strip for holding together pieces of glass in a leaded light or stained glass window.
A quick-setting binder for mortars etc. Examples are ordinary Portland cement and 'natural' cements (such as Roman cement).
A wet mixture of lime and coarse sand used as a plaster, render undercoat or mortar. Can contain hair, especially if used for plastering.
Where the rooms immediately below a roof space are fully insulated and sealed at ceiling level against the loss of heat and water vapour. The roof void, therefore, becomes cold.
One of a series of ordinary timber rafters of equal cross-sectional size that do not form part of a roof truss although they may be carried by one where their loads are transferred onto heavier, principal rafters by purlins. They support the groundwork onto which tiles or slates are fixed.
The process of maintaining and managing change to a heritage asset in a way that sustains and, where appropriate, enhances its significance (as defined in the National Planning Policy Framework 2012).
A batten laid at right angles to, and over or under, other battens; or the process of laying battens at right angles to other battens.
The process of removing hard mortar from joints with a hammer and chisel etc prior to repointing (cf raking out).
D
Flint found already free from its chalk matrix (cf virgin flint). Can be obtained from fields, riverbeds, beaches or gravel pits.
A World Heritage Site, Scheduled Monument, Listed Building, Protected Wreck Site, Registered Park and Garden, Registered Battlefield or Conservation Area designated under the relevant legislation (as defined in the National Planning Policy Framework 2012).
An upright window, usually with its own roof, that is built into a pitched roof and lights a room within it.
The overlap formed by the tail of a tile or slate lying over two courses below.
E
The lowest and/or overhanging edge of a roof (cf verge). Where the lowest edge, it is detailed to shed rainwater, frequently into a gutter.
F
A wet mixture of lime and fine sand used as a plaster finishing coat or pointing mortar for ashlar.
The technique of setting knapped flints on the same plane (ie flush) with the face of dressed stone. Used to form decorative compositions in superior work. Two main types:
(i) Flint infilling between stone slabs mortared onto face of wall to create chequer patterns, bands etc.
(ii) Inlays of flint set into carefully shaped recesses in stone slabs, forming, for example, trefoil-headed panels or heraldic shields.
G
A hipped roof with a small gable at the ridge or the vernacular equivalent of a mansard roof.
Use of lightly fired bricks (called rubbers or rubbing bricks), of a uniform, sandy consistency, that can be cut or rubbed to allow fine joints in arches or quoins.
H
With double-lap tiling or slating, the length by which a course overlaps the next but one below.
A building, monument, site, place, area or landscape identified as having a degree of significance meriting consideration in planning decisions, because of its heritage interest. Heritage asset includes designated heritage assets and assets identified by the local planning authority, including local listing (as defined in the National Planning Policy Framework 2012).
The external angle formed where the sides of two adjacent roof slopes meet (cf valley). It occurs where the end of a pitched roof is sloping, rather than, as with a gable, standing vertically.
All aspects of the environment resulting from the interaction between people and places through time, including all surviving physical remains of past human activity, whether visible, buried or submerged, and landscaped and planted or managed flora.
Information services that seek to provide access to comprehensive and dynamic resources relating to the historic environment of a defined geographic area for public benefit and use.
Calcium hydroxide (Ca(OH)2) formed as a dry powder when any lime is slaked using an exact amount of water (cf lime putty). Not to be confused with hydraulic lime. It is possible to obtain hydrated hydraulic lime or hydrated non-hydraulic lime.
(i) Natural hydraulic limes are prepared from limestone with reactive silica and alumina impurities. The lime reacts with the impurities in the presence of water to form calcium silicates and aluminates (cf non-hydraulic lime), in addition to the calcium carbonate that contributes to the hardening process when exposed to the air. They are classified under BS EN 459: Part 1: 2001 as NHL 2, 3.5 or 5, in order of increasing strength.
(ii) Natural hydraulic limes with an additive are classified as NHL-Z, while HL denotes an artificial hydraulic lime. Since manufacturers do not have to state whether the additives include Portland cement or hwat the percentages are, these products should be avoided in conservation work.
K
Flint that has been deliberately struck to present an approximately flush face for aesthetic purposes (cf fractured flint). Nodules are broken ('quartered') into workable pieces along the natural lines of fracture. For the finest work, this is followed by chipping away ('flaking') to even the surface and square the end.
Reworking mortar that has been stiffened up in order to restore the workability.
L
A milky layer of lime or cement on the surface of the mortar, the result of using too much water in the mix, overworking the mortar or rapid drying.
The traditional binder for mortar, plaster, render and limewashes etc. Two main types: hydraulic and non-hydraulic.
Calcium hydroxide (Ca(OH)2) formed as a paste when a non-hydraulic or weak (NHL 2) hydraulic lime is slaked in an excess of water and the milky suspension is allowed to settle. Can also be made by mixing hydrated lime (the form widely available in builders' merchants) and water, although this gives a less workable mix with inferior plasticity and binding properties.
The plan for the future development of the local area, drawn up by the local planning authority in consultation with the community. In law this is described as the development plan documents adopted under the Planning and Compulsory Purchase Act 2004. Current core strategies or other planning policies, which under the regulations would be considered to be development plan documents, form part of the Local Plan. The term includes old policies which have been saved under the 2004 Act.
The public authority whose duty it is to carry out specific planning functions for a particular area. All references to local planning authority apply to the district council, London borough council, county council, Broads Authority, National Park Authority and the Greater London Authority, to the extent appropriate to their responsibilities.
The public authority whose duty it is to carry out specific planning functions for a particular area. All references to local planning authority apply to the district council, London borough council, county council, Broads Authority, National Park Authority and the Greater London Authority, to the extent appropriate to their responsibilities.
M
Walling constructed of units (stone, brick etc) set in mortar or the craft of wall and vault building.
A mixture of aggregate and binder that hardens after application and is used for bedding and pointing masonry units.
N
A plan prepared by a Parish Council or Neighbourhood Forum for a particular neighbourhood area (made under the Planning and Compulsory Purchase Act 2004).
Lime prepared from a relatively pure limestone containing no significant amounts of reactive silica and alumina. It is classified as CL under European standards. The purest type is described as 'fat', the less pure as 'lean'. The impurities in the latter impart a slight hydraulicity but not enough for the lime to be called 'hydraulic'. These limes will harden initially by drying out and in the longer term by absorbing carbon dioxide form the air to form calcium carbonate ('carbonation'). They cannot harden under water (cf hydraulic lime).
P
A measure of the rate at which a liquid or vapour passes through a solid material, usually expressed as grams of the liquid or vapour transmitted through a given area of the solid material in 24 hours. Pores must be interlinked (cf porosity).
Ratio of the volume of pore space to total volume of a solid material, usually expressed as a percentage. Pores may or may not be interlinked (cf permability).
A material containing reactive silica and alumina that can be used to impart a hydraulic set to a non-hydraulic lime mix, or to confer a faster set upon a naturally hydraulic lime or Portland cement. Typical pozzolanic materials are volcanic ashes and lightly-fired clays, crushed and ground bricks.
One of the larger rafters that, if present, forms the upper part of a timber roof truss. It carries the purlins, which, in turn, support common rafters.
A member running along the length of a roof frame to provide support for common rafters at their mid-spans or for profiled sheeting. Carried by trusses or cross-walls.
Q
Calcium oxide (CaO), the unstable material produced when limestone has been burnt but not slaked.
R
One of the inclined members that forms the top of the frame that supports a roof and determines its pitch.
The process of removing loose mortar from joints with a small tool prior to repointing (cf cutting out).
The brand name of an early patent cement prepared from naturally occurring 'cement stones' that contain clay and limestone. Widely used to describe all natural cements of the 19th century. Although used principally as a rendering material, it was used also in 19th-century pointing, especially in restoration and repair.
S
The surroundings in which a heritage asset is experienced. Its extent is not fixed and may change as the asset and its surroundings evolve. Elements of a setting may make a positive or negative contribution to the significance of an asset, may affect the ability to appreciate that significance or may be neutral (as defined in the National Planning Policy Framework 2012).
Sand comprising predominantly coarse, harsh, angular grains (cf soft sand).
The value of a heritage asset to this and future generations because of its heritage interest. That interest may be archaeological, architectural, artistic or historic. Significance derives not only from a heritage asset’s physical presence, but also from its setting (as defined in the National Planning Policy Framework 2012).
Combination of quicklime with water to form calcium hydroxide (Ca(OH)2) in the form of lime putty or dry hydrate.
T
Lime mortar applied to the underside of tiles or slates to check the entry of wind, blown snow and dust through gaps. It also helps to hold tile pegs in place.
V
The internal angle formed where the sides or bottoms of two adjacent or opposing roof slopes meet (cf hip or ridge).
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