Home improvements or repairs Have Never Been Easier. Now you can learn
to understand some of the trade Jargon..
Aggregate: Pebbles, shingle, gravel etc. used in the manufacture
of concrete, and in the construction of "soakaways".
Airbrick: Perforated brick used for ventilation, especially to
floor voids (beneath timber floors) and roof spaces.
Architrave: Joinery moulding around window or doorway.
Asbestos: Fibrous mineral used in the past for insulation. Can be a
health hazard specialist advice should be sought if asbestos (especially
blue asbestos) is found.
Asbestos Cement: Cement with 10-15% asbestos fibre as
reinforcement. Fragile will not bear heavy weights. Hazardous fibres may
be released if cut or drilled.
Ashlar: Finely dressed natural stone: the best grade of masonry.
Asphalt: Black, tar-like substance, strongly adhesive and
impervious to moisture. Used on flat roofs and floors.
Barge Board: (See Verge Board)
Balanced Flue: Common metal device normally serving gas
appliances which allows air to be drawn to the appliance whilst also
allowing fumes to escape.
Beetle Infestation: (Wood boring insects: woodworm) Larvae of
various species of beetle which tunnel into timber causing damage.
Specialist treatment normally required. Can also affect furniture.
Benching: Smoothly contoured concrete slope beside drainage
channel within an inspection chamber. Also known as Haunching.
Bitumen: Black, sticky substance, related to asphalt. Used in
sealants, mineral felts and damp-proof courses.
Breeze Block: Originally made from cinders ("breeze") the term
now commonly used to refer to various types of concrete and cement
Carbonation: A natural process affecting the outer layer of
concrete. Metal reinforcement within that layer is liable to early
corrosion, with consequent fracturing of the concrete.
Cavity Wall: Standard modern method of building external walls
of houses comprising two leaves of brick or blockwork separated by a gap
("cavity") of about 50mm (2 inches).
Cavity Wall Insulation: Filling of wall cavities by one of
various forms of insulation material - Beads: Polystyrene beads pumped
into the cavities. Will easily fall out if the wall is broken open for
any reason - Foam: Urea formaldehyde form, mixed on site, and pumped
into the cavities where it sets. Can lead to problems of dampness and
make replacement of wall-ties more difficult - Rockwool: Inert mineral
fibre pumped into the cavity.
Cavity Wall - Tie: Metal device bedded into the inner and outer
leaves of cavity walls to strengthen the wall. Failure by corrosion can
result in the wall becoming unstable specialist replacement ties are
Cesspool: A simple method of drain comprising a holding tank
that needs frequent emptying. Not to be confused with Septic Tank.
Chipboard: Also referred to as "particle board". Chips of wood
compressed and glued into sheet form. Cheap method of decking to flat
roofs, floors and (with Formica or melamine surface) furniture,
especially kitchen units.
Collar: Horizontal timber member intended to restrain opposing
roof slopes. Absence, removal or weakening can lead to Roof Spread.
Combination Boiler: Modern form of gas boiler which activates on
demand. With this form of boiler there is no need for water storage
tanks, hot water cylinders etc and generally the pressure is much better
Condensation: Occurs when warm moist air meets a cold surface.
The water in the air then either settles as water droplets on the
surface (as it does on windows for example), or if the surface is
absorbent, it soaks into the surface. In the latter case condensation is
often not noticed unless or until mould appears. (See also Ventilation)
Coping / Coping Stone: Usually stone or concrete, laid on top of a wall
as a decorative finish and to stop rainwater soaking into the wall.
Corbell: Projection of stone, brick, timber or metal jutting out
from a wall to support a weight.
Cornice: Ornamental moulded projection around the top of a
building or around the wall of a room just below the ceiling.
Coving: Curved junction between wall and ceiling or (rarely)
between ceiling and floor.
Dado Rail: Wooden moulding fixed horizontally to a wall,
aprroximately 1 metre above the floor, originally intended to protect
the wall against damage by chair-backs now very much a decorative
Damp Proof Course: (DPC) Course Layer of impervious material
(mineral felt, pvc etc) incorporated into a wall to prevent dampness
rising up the wall or lateral dampness around windows, doors etc.
Various proprietary methods are available for damp proofing existing
walls including "electro-osmosis" and chemical injection.
Deathwatch Beetle: (Xestobium Refovillosum) Serious insect pest
in structural timbers, usually affects old hardwoods with fungal decay
Double Glazing: A method of thermal insulation usually either:
Sealed unit: Two panes of glass fixed and hermetically sealed together;
or Secondary: In effect a second "window" placed inside the original
Downpipes: Drainage pipes from guttering.
Dry Rot: (Serpula Lacrymans) A fungus that attacks structural
and joinery timbers, often with devastating results. Can flourish in
moist, unventilated areas. Not to be confused with wet rot.
Eaves: The overhanging edge of a roof.
Efflorescence: Salts crystallised on the surface of a wall as a
result of moisture evaporation.
Engineering Brick: Particularly strong and dense type of brick,
sometimes used as damp-proof course.
Fibreboard: Cheap, lightweight board material of little
strength, used in ceilings or as insulation to attics.
Flashing: Building technique used to prevent leakage at a roof
joint. Normally metal (lead, zinc, copper) but can be cement, felt or
Flaunching: Contoured cement around the base of chimney pots, to
secure the pot and to throw off rain.
Flue: A smoke duct in a chimney, or a proprietary pipe serving a
heat-producing appliance such as a central heating boiler.
Flue Lining: Metal (usually stainless steel) tube within a flue
essential for high output gas appliances such as boilers. May also be
manufactured from clay and built into the flue.
Foundations: Normally concrete, laid underground as a structural
base to a wall - in older buildings may be brick or stone.
Frog: A depression imprinted in the upper surface of a brick, to
save clay, reduce weight and increase the strength of the wall. Bricks
should always be laid frog uppermost.
Fused Spur: Power socket that does not have a plug going into
it, instead the cable from an appliance like a fridge, radiator, burglar
alarm etc and has a fuse socket built into it.
Gable: Upper section of a wall, usually triangular in shape, at
either end of a ridged roof. - Gable end.
Gang: Referred to for 13amp power pints 1 gang = 1 single socket
2 gang = 1 double socket.
Ground Heave: Swelling of clay sub-soil due to absorption of
moisture: can cause an upward movement in foundations.
Gully: An opening into a drain, normally at ground level, placed
to receive water etc. from downpipes and wastepipes. Haunching: See
Benching.It is also a term used to describe the support to a drain
Hip: The external junction between two intersecting roof slopes.
Inspection Chamber: Commonly called a man hole. Access point to
a drain comprising a chamber (of brick, concrete or plastic) with the
drainage channel at its base and a removable cover at ground level.
Jamb: Side part of a doorway or window.
Joist: Horizontal structural timber used in flat roof, ceiling
and floor construction. Occasionally also metal.
Landslip: Downhill movement of unstable earth, clay, rock etc.
often following prolonged heavy rain or coastal erosion, but sometimes
due entirely to sub-soil having little cohesive integrity.
Lath: Thin strip of wood used in the fixing of roof tiles or
slates, or as a backing to plaster. Lath and plaster walls were very
common in houses from late 1800,s to 1950's
Lintel: Horizontal structural beam of timber, stone, steel or
concrete placed over window or door openings.
LPG: Liquid Petroleum Gas or Propane. Available to serve gas
appliances in areas without mains gas. Requires a storage tank.
Man Hole: - See Inspection Chamber
Mortar: Mixture of sand, cement, lime and water, used to join
stones or bricks.
Mullion: Vertical bar dividing individual lights in a window.
Newel: Stout post supporting a staircase handrail at top and
bottom. Also, the central pillar of a winding or spiral staircase.
Oversite: Rough concrete below timber ground floors: the level
of the oversite should be above external ground level.
Parapet: Low wall along the edge of a flat roof, balcony etc.
Pier: A vertical column of brickwork or other material, used to
strengthen the wall or to support a weight.
Plasterboard: Stiff "sandwich" of plaster between coarse paper.
Now in widespread use for ceilings and walls.
Pointing: Smooth outer edge of mortar joint between bricks,
Powder Post Beetle: (Bostrychidae or Lyctidae family of beetles)
A relatively uncommon pest that can, if untreated, cause widespread
damage to structural timbers.
Purlin: Horizontal beam in a roof upon which rafters rest.
Quoin: The external angle of a building; or, specifically, bricks or
stone blocks forming that angle.
Rafter: A sloping roof beam, usually timber, forming the carcass
of a roof. Random Rubble: Primitive method of stone wall construction
with no attempt at bonding or coursing.
Rendering: Vertical covering of a wall either plaster
(internally) or cement (externally), sometimes with pebbledash, stucco
or Tyrolean textured finish.
Reveals: The side faces of a window or door opening. Ridge: The
apex of a roof.
Riser: The vertical part of a step or stair.
Rising Damp: Moisture soaking up a wall from below ground, by
capillary action causing rot in timbers, plaster decay, decoration
Roof Spread: Outward bowing of a wall caused by the thrust of a
badly restrained roof carcass (see Collar).
Screed: Final, smooth finish of a solid floor, usually cement,
concrete or asphalt.
Septic Tank: Tank Drain installation whereby sewage decomposes
through bacteriological action, which can be slowed down or stopped
altogether by the use of chemicals such as bleach, biological washing
powders etc. Not to be confused with Cesspool.
Settlement: General disturbance in a structure showing as
distortion in walls etc., possibly a result of major structural failure,
very dry weather conditions etc. Sometimes of little current
significance. (See also Subsidence)
Shakes: Naturally occurring cracks in timber; in building
timbers, shakes can appear quite dramatic, but strength is not always
Shingles: Small rectangular slabs of wood used on roofs instead
of tiles, slates etc.
Soakaway: Arrangement for disposal of rainwater, utilising
graded aggregate laid below ground.
Soaker: Sheet metal (usually lead, copper or zinc) at the
junction of a roof with a vertical surface of a chimneystack, adjoining
wall etc. Associated with flashings that should overlay soakers.
Soffit: The under-surface of eaves, balcony, arch etc. Solid
Fuel: Heating fuel, normally coal, coke or one of a variety of
Spandrel: Space above and to the sides of an arch; also the
space below a staircase.
Stud Partition: Lightweight, sometimes non-load bearing wall
construction comprising a framework of timber faced with plaster,
plasterboard or other finish.
Subsidence: Ground movement, generally downward, possible a
result of mining activities or clay shrinkage.
Sub-soil: Soil lying immediately below the topsoil, upon which
foundations usually bear.
Sulphate Attack: Chemical reaction activated by water, between
tricalcium aluminate and soluble sulphates. Can cause deterioration in
brick walls and concrete floors.
Tie Bar: Heavy metal bar passing through a wall, or walls, to
brace a structure suffering from structural instability.
Torching: Mortar applied on the underside of roof tiles or
slates to help prevent moisture penetration. Not necessary when a roof
is underdrawn with felt.
Transom: Horizontal part of a step or stair.
Tread: The horizontal part of a step or stair.
Trussed Rafters: Method of roof construction utilising
prefabricated triangular framework of timbers. Now widely used in
Underpinning: Method strengthening weak foundations whereby a
new, stronger foundation is placed beneath the original.
Valley Gutter: Horizontal or sloping gutter, usually
lead-or-tile-lined, at the internal intersection between two roof
Ventilation: Necessary in all buildings to disperse moisture
resulting from bathing, cooking, breathing etc. and to assist in
prevention of condensation. Floors -necessary to avoid rot, especially
Dry Rot; achieved by airbricks near to ground level. Roofs - necessary
to disperse condensation within roof spaces; achieved either by
airbricks in gables or ducts at the eaves. (see Condensation)
Verge: The edge of a roof, especially over a gable.
Verge Board: Timber, sometimes decorative plastic material,
placed at the verge of a roof: also known as bargeboard.
Wainscot: Wood panelling or boarding on the lower part of an
Wall Plate: Timber placed at the eaves of a roof, to take the
weight of the roof timbers.
Wastepipe: Drainage pipe for baths, basins, wc's.
Wet Rot: (Coniophora Puteana) Decay of timber due to damp conditions.
Not to be confused with the more serious Dry Rot.
Woodworm: Colloquial term for beetle infestation: usually
intended to mean Common Furniture Beetle (Anobium Punctatum): by far the
most frequently encountered insect attack in structural and joinery