FAQs: Glossary

We do our best to offer a jargon-free service, but often need to use terms that might not be familiar to all.

The following is a list of key terms that we use on a regular basis and our (hopefully!) simple explanations.

Search Glossary:

Building Regulations

Definition – Minimum standards for design, construction and alterations to virtually every building. They are developed by the Government and approved by Parliament. They came into force in 1966 and the current Regulations were approved in 2010, with amendments added to the present day.

Part A – Structure

  • A1 – Loading
  • A2 – Ground Movement
  • A3 – Disproportionate Collapse

Part B – Fire Safety

  • B1 – Means and warning of Escape
  • B2 – Internal Fire Spread (Linings)
  • B3 – Internal Fire Spread (Structure)
  • B4 – External Fire Spread
  • B5 – Access and facilities for the fire service

Part C – Contamination

  • C1 – Site preparation and resistance to contaminates
  • C2 – Resistance to Moisture

Part D – Toxic Substances

  • D1 – Cavity Insulation

Part E – Sound Proofing

  • E1 – Protection against sound from other parts of the building and adjoining buildings
  • E2 – Protection against sound within a dwelling house etc.
  • E3 – Reverberation in the common internal parts of buildings containing flats or rooms for residential purposes
  • E4 – Acoustic conditions in schools

Part F – Ventilation

  • Means of Ventilation

Part G –  Sanitation, Water Heating and Efficiency

  • G1 – Cold water supply
  • G2 – Water efficiency
  • G3 – Hot water supply and systems
  • G4 – Sanitary Conveniences and Washing Facilities
  • G5 – Bathrooms
  • G6 – Food preparation areas

Part H – Drainage and Waste Disposal

  • H1 – Foul water drainage
  • H2 – Wastewater treatment systems and cesspools
  • H3 – Rainwater Drainage
  • H4 – Building over sewers
  • H5 – Separate systems of drainage
  • H6 – Solid waste storage

Part J – Combustion Appliances and Fuel Storage Systems

  • J1 – Air supply
  • J2 – Discharge of products of combustion
  • J3 – Warning of release of carbon monoxide
  • J4 – Protection of building
  • J5 – Provision of information
  • J6 – Protection of liquid fuel systems
  • J7 – Protection against pollution

Part K – Protection from falling, collision and impact

  • K1 – Stairs, ladders and ramps
  • K2 – Protection from falling
  • K3 – Vehicle Barriers and loading bays
  • K4 – Protection against impact with glazing
  • K5 – Additional provisions for glazing in buildings other than dwellings
  • K6 – Protection against impact from and trapping by doors

Part L – Energy Conservation

  • L1a – Conservation of fuel and power in new dwellings
  • L1b – Conservation of fuel and power in existing dwellings

Part M – Access and Use of Buildings

  • Category 1 – Visitable dwelling
  • Category 2 – Accessible and adaptable dwellings
  • Category 3 – Wheelchair user dwellings

Part P – Electrical Safety

  • P1 – Design and installation of electrical installations

Part Q – Security

  • Q1 – Unauthorised access

Part R – Broadband

  • R1 – In building physical infrastructure

Listed Buildings

  • Grade I – of exceptional interest
  • Grade II* – Important buildings of more than special interest
  • Grade II – Of special interest, efforts must be made to preserve

Listed Building Consent will likely be required for any internal or external changes to all Listed property

Building Pathology


Apron – a metal strip (usually lead or zinc) used as a seal. Often fitted to chimney stacks and tile hanging.

Cowl – a cover often fitted to a chimney flue to prevent rain penetration and debris falling into the fireplace

Flaunching – sloping fillet of cement or mortar embedding the base of a chimney pot

Flashings – weather proofing used to keep the base of the chimney stack water tight. Typically of lead construction on modern property. Unmodernised older properties and thatched properties will likely have cement fillet flashings.

Gutter Flashings – Strip of weatherproofing, typically of lead construction, placed at the point where the chimney intersects with the roof pitch to divert rainwater way from the stack

Roof Coverings

Asphalt –  black, tar-like substance impervious to moisture. Used on flat roofs and floors.

Coping Stones – usually a row of overhanging slabs, typically of concrete construction, placed on top of a parapet wall to protect the mortar joints to brickwork. Typically coping stones have a ‘drip cut’ groove on the underside of the overhang to deflect rainwater and help prevent frost damage

Cover Flashing – vertical flashing overlapping the vertical upturned parts of a roof covering or other flashing.

Fall – a slope, typically to a ‘flat’ roof, designed to allow water to drain away.

Fillet Cement Flashing– mortar used to seal a junction, usually between roofs and brickwork in older property. Lead flashings are now commonly used.

Finial – Decorative element used at the top of a gable newel post or fence post

Flashing – a seal, usually between a roof and wall or chimney. Normally of lead construction but can be felt or other material.

Flat felt roof – common type of flat roof made from built up layers of felt. Affordable, but often fails suddenly and needs regular maintenance and re-covering every 10 to 15 years or so.

Hip – the junction between the slopes at the angled end of a roof.

Hip iron – galvanised steel or wrought iron bar secured to the front of a hip rafter to hold hip tiles in place

Hip Tile – a curved or angular tile fitting over the junction of the roof slopes at a hip.

Mansard Roof – A roof with four sloping sides and two pitches, with the lower pitch steeper than the upper pitch

Mortar bed – mortar beneath roof ridge tiles

Pan tiles – interlocking tiles

Parapet wall – low protective wall along the edge of a roof, bridge or balcony

Ridge – the highest part or apex of a roof.

Ridge Tile – Tile for covering the ridge of a roof and making it weather tight.

Roof Deck – usually timber or ply boarding to a flat roof below the waterproof layer.

Seamsil – flexible silicone remedial system used to treat cut edge corrosion on steel roofing and other situations where exposed metal is vulnerable to moisture

Shingles – wooden or slate roof or wall tiles, placed in overlapping rows

Soaker flashing– piece of flexible metal fitted to interlock with slates or tiles and make a watertight joint between a wall and a roof or at a hip or valley.

Thatched Roof Covering – three common types of thatched roofs are made of Water Reed, Wheat Reed and Long Straw. Typically, thatched roofs require regular maintenance and require replacement every 25-30 years (Wheat Reed) or 15-20 years (Long Straw), depending on location and environmental factors. Ridges require replacing every 10-15 years. Water Reed is particularly durable and roofs of this material can last 50-70 years.

Tingle– strip of metal used to secure edges of sheet metal and slipped slate tiles at drips, rolls and seams


  1. Combination of mortar and hair (usually horse hair) traditionally trowled into gaps between tiles inside a roof for weather protection. Not done so much nowadays.
  2. Mortar on the underside of clay tiles


  1. Tiles or compressed cement board laid at the verge of a roof to prevent water dripping over the edge
  2. Lower sheet metal of a drip, roll or seam

Verge– the edge of a sloping roof which overhangs the gable. Verges are often finished with mortar and a barge board below.

Rainwater Pipes and Gutters

Box Gutter – square shaped gutter, often found behind a parapet wall.

Cut/lapped in Valley – a gutter at the junction of two roofs where the slates or tiles are cut to meet on the valley line.

Downpipe – vertical pipe which brings rainwater to ground level from roof gutters or waste water from hoppers.

Finlock Concrete – used in guttering. Often lined witgh aluminium or sealed with bitumen. Used in the 1950s and 60s but are prone to failure

Gulley – an opening into which rain and waste water are collected before entering the drain.

Gutter – a channel along the eaves of a roof or the edge of a path for the removal of rainwater.

Hopperhead – funnel shaped enlargement at the top of a downpipe whee the gutter rainwater is received

Open Valley – valley gutter in which the adjoining slates or tiles are so cut that the lead or fiberglass lining is exposed. Open valley gutters are less prone to blockages than cut valleys.

Parapet Gutter – a gutter usually provided with a flexible metal or other impervious lining. Used behind a parapet or sometimes at a valley. Frequently hidden and often a source of damp.

Valley Gutter – horizontal or sloping gutter, usually lead-or-tile-lined, at the internal intersection between two roof slopes.

Main Walls

Abutment – an intersection, usually between a roof and a wall.

Aerated Concrete (Aircrete) – lightest concrete block, usually limited to low rise construction or non load bearing partitions

Aggregate – Granular material used in concrete, road constructions, mortars and plaster

Airbrick – a perforated brick, terracotta or plastic vent built into a wall for providing ventilation. Often used to ventilate the underside of timber ground floors, fireplaces or a roof space.

Apron – a metal strip, usually lead or zinc, used as a seal. Often fitted to a section of wall below a window.

Ashlar Stone – smooth finished stone

Bellmouth/Drip Bead –   thickening out of render, in a curved shape, to form a drip to deflect water. Usually found at the base of a wall, above the damp-proof course.

Binder – 3. material used to bind together a mixture, e.g. cement in concrete mortar

Bitumen – Tar used for roofing, damp proofing and road surfacing

Bond –  the regular arrangements of bricks, blocks or stones in a wall so that the units may be joined together.

Bonding Timbers – timbers built into the walls in older houses to provide restraint. Unfortunately, these can easily rot and are often affected by wood-boring insect attack

Breeze blocks – concrete blocks made from cinders, an industrial waste product

Buttress – stone or brick structure built against a wall to support it i.e. to resist active thrust

Cavity Wall – traditional modern method of building external walls of houses comprising two leaves of brick or blockwork usually separated by a cavity of about 5Omm and held together with galvanized metal ties. The wall cavity is now usually insulated.

Cavity Wall Insulation –  filling of wall cavities by one of various forms of insulation material including polystyrene beads, foam, fiberglass or mineral Wool.

Cavity Wall Tie – a twisted piece of galvanized metal bars(coated in zinc to prevent rust), bedded into the inner and outer leaves of cavity walls intended to strengthen the wall. Failure by corrosion can result in the wall becoming unstable. Replacement ties are then required.

Cellular – materials or products produced with small internal voids or hollow internal structures. Lightweight and improves thermal insulation, but reduces strength and resistance to impact damage

Cement – a binder used in concrete and mortar. Portland cement is the most common worldwide. Main ingredients calcium carbonate (from chalk or limestone) Silica and Alumina  (from clay or shale)

Cladding – the non-loadbearing external skin of a wall or roof used to keep the weather out. Can be tiles, timber or composite material.

Clinker blocks – concrete blocks made from blast furnace slag, an industrial waste product

Concrete – mixture of graded aggregates, cement, water and air

Corbel –  projection of stone, brick, timber or metal jutting out from a wall to support a weight above.

Course – horizontal layer of bricks, blocks, slates etc. including any mortar laid with them.

Crown – the top of an archway.

Damp-Proof Course (or DPC) – layer of impervious material (slate, bitumen, PVC etc.) incorporated into a wall and designed to prevent dampness rising up the wall from rainwater splash back.

Damp-Proof Membrane – horizontal layer of impervious material (usually polythene or bitumen). Incorporated into floors or slabs.

Dense aggregate block – made from cement, sand and aggregates. Durable, high thermal mass and strength

Engineering Brick – particularly strong and dense type of brick, often used as a damp proof course in older buildings.

English Bond – a traditional form of solid wall construction with brick courses (layers) laid with headers (the short end) laid alternately with stretchers (the long side).

Flat flared arch – curved arch shaped lintel, typically in Victorian properties

Flemish Bond – a traditional form of solid wall construction with the bricks laid with headers (the short end) laid alternately with stretchers (the long side).

Gable – upper section of a wall, usually triangular in shape, at either end of a ridged roof.

Headers – short face of brickwork

Lightweight block – cement made from aggregates. Higher insulation properties and light weight

Lintel – a horizontal beam over a door or window opening usually carrying the load of the wall above.

Load-Bearing – usually applied to walls or other structures which carry loadings from walls, floors or roof at higher level.

Mortar – Workable paste used to bind building blocks

Padstone – engineered brick or concrete that bears and spreads the load of a lintel, girder or roof truss

Pattress plate – circular restraints for providing load bearing stress on masonry structures

Perpend – vertical joint in masonry construction

Pier – a vertical column of brickwork or other material, used to strengthen the wall or to support a weight.

Pointing – external part of mortar joints in masonry construction

Quoins – brick or stone corner stones

Rendering – cement or lime covering of a wall either internally or externally, sometimes with pebbledash or textured finish.

Shiplap – horizontal external boarding, usually timber or uPVC

Soldier – upright, vertical brick usually seen on a lintel

Stretchers – long face of brickwork

Tie Bar– metal bar passing through a wall, or walls, bracing the structure. Often used to correct bulging walls.

Wall plate– structural element that distributes a load onto a wall and acts as a mini lintel


Brise Soleil – shade used above windows with vertical and horizontal slats that reduce glare and solar gain

Cames – The lead bars in leaded windows.

Casement Window – a window composed of hinged, pivoted or fixed sashes.

Crittle Windows – Metal alloy, like aluminium, with slim frames. Typically used in 1920s and 1930s

Fenestration – refers to the way in which windows have been arranged on the outside of a building

Rivial – window recess

Dormer – a window built out from a roof slope.

Dormer Cheek – the vertical side of a dormer window.

Double Glazing – a method of thermal and sound insulation usually either with sealed units or secondary glazing.

Double Hung – a window in which the opening lights slide vertically within a cased Sash Window frame, counter balanced by weights supported on sash cords that pass over pulleys in the frame.

Drip – groove under an overhanging edge (e.g. window cill) designed to stop water running down the face of the building.

Fanlight – a window above a door or casement.

Mullion – vertical bar dividing individual lights in a window.

Reveals – the side faces of a window or door opening.

Secondary Glazing – additional layer of glazing fixed in its own frame within a window opening.

Transom – horizontal bar of wood or stone across a window or top of door.

Outside Doors

Mortice Lock– lock set within the door thickness.

Reveals– the side faces of a window or door opening.

Transom– horizontal bar of wood or stone across a window or top of door.

Water Bar– small metal bar rising above the level of threshold to a door to prevent water blowing below it.

Weather Strip– moulding fitted at the base of an external door to throw water clear from the threshold below.

Other External Joinery

Barge board– board fastened to projecting gables of a roof to give them strength and provide protection and concealement to timbers or purlins

Cruck Beams–  pairs of curved timbers, which run from ground level and meet at the ridge.

Fascia – Vertical board placed on the eaves of a roof. Covers the edge of rafters and provides a surface for gutters

Soffit board– horizontal flat board or lining placed under the overhanging parts of the eaves or rafter feet

Roof Structure


  1. Horizontal beam in a roof that the tiles are hung on
  2. thin long strip of material (usually wood) used to strengthen or secure something

Birdsmouth – A V shaped notch at the bottom of a rafter that allows the rafter to rest on the wall plate

Bitumen – Tar used for roofing, damp proofing and road surfacing

Building Paper – Heavy-duty paper, usually incorporating a bitumen layer. Was often used as a lining under roof tiles in the 1960’s. Tears easily.

Butterfly Roof – ‘M’ shaped roof usually hidden at the front with a parapet wall. The hidden central valley gutters are often a source of nuisance.

Cellotex insulation – compressed foam insulation

Collar – horizontal timber member designed to restrain opposing roof slopes. Absence, removal or weakening can lead to roof spread.

Eaves – the overhanging lower edge of a roof.

Ladder purlin – used in loft extensions to reduce load bearing weight. Vertical as opposed to horizontal

Mansard Roof – pitched roof which has, on each side, a shallower upper slope and a steeper lower slope.

Purlin – horizonal beam along the length of a roof, resting on principals and supporting common rafters or boards

Rafter – a sloping roof beam, usually timber, forming the carcass of a roof.

Ring Beam – like a purlin but circles a roof structure. Seen in bungalows and hipped roofs

Roof Void– unused space between the roof and the ceiling of the highest storey (often called the loft or attic).

Sarking Felt– felt or other lining laid across rafters of a pitched roof to provide a secondary means of defence against water penetration.

Strut – a support, usually a roof timber.

Trussed Rafters – Timber and Truss method of roof construction utilizing prefabricated triangular framework of timbers.

Upstand– turned up edge of a flat surface or sheeting, especially in a roof space where it meets the roof


Anaglypta – a type of thick emobssed wallpaper designed to be painted over. Also used on ceilings.

Binder – 2. a horizontal timber used in pitched roofs and suspended ceilings fixed across the top of ceiling joists to provide intermediate support and thus stiffen them

Cornice – ornamental molding around the wall of a room, just below the ceiling

Coving – curved junction between wall and ceiling.

Fibreboard – Fibre board – timber product comprised of wood fibres e.g. MDF (medium density fibreboard) that was used in ceilings, or as insulation to attics. Considered to be a fire risk and usually best removed. Some of the paper backings to fibreboard can contain asbestos.

Hanger – a tie, chain, strap, threaded bar or fixing that is used to secure fittings, fixtures, mechanical units and suspended ceilings to a structure. The length of a hanger needs to be adjustable

Lath – thin, narrow strip of straight, grained wood used under roof shingles/tiles, on lath and plaster ceilings and walls and also in lattis and trellis work

Plasterboard – sandwich of plaster between paper. Commonly used for ceilings and partition walls.

Walls and Partitions

Anaglypta – a type of thick emobssed wallpaper designed to be painted over. Also used on ceilings.

Dot and Dab – process of attaching plasterboard to a wall using dots of plasterboard adhesive

Dry lining – lining to an interior wall that doesn’t need to be plastered

Frieze – The area of an internal wall above the picture rail.

Gasket – flexible material used to seal gap between two objects to prevent air leakage and water penetration

Key – the roughness of a surface, which provides a bond for any application of paint, plaster, rendering, tiles etc., or spaces between laths or wire meshes which provide a grip for plaster.

Lagging   2. Timber frame used to support sides when building an arch

Lath – thin, narrow strip of straight, grained wood used under roof shingles/tiles, on lath and plaster ceilings and walls and also in lattis and trellis work

Partition – wall between rooms usually non-load bearing.

Plasterboard – sandwich of plaster between paper. Commonly used for ceilings and partition walls.

RSJ – frequently used abbreviation for a Rolled Steel Joist.

Scrim – coarse mesh used for bridging the joint between plasterboard sheets to prevent cracking. Used to be cotton or canvas, now mainly plastic.

Stud Partition – lightweight, sometimes non-load bearing wall construction, comprising a framework of timber faced with plaster, plasterboard or other finish.

Wattle and Daub – An arrangement of small timbers (wattle) form a lattice to support a mud-based filling (daub), generally made up of clay, lime and chalk/limestone dust, aggregates such as earth, sand and crushed chalk/stone and straw, hair (usually horse hair), flax, hay and grass to help hold it all together. Historically, the surface was normally lime plastered or lime washed once the daub had hardened. 


Asphalt – black, tar-like substance impervious to moisture. Used on flat roofs and floors.

Binder – A timber or metal beam used in double floors to provide intermediate support for bridging joists

Cork Expansion Joint – seen ibn laminate and wood laminate flooring to allow flex in temperature variation

Flagstones – large stones used as an attractive floor finish.

Footings – older, usually shallow, form or foundation of brick or stone.

Foundations – normally concrete, laid underground as a structural base to a wall; These may be brick or stone in older buildings.

Hardcore – broken bricks or stone which, consolidated, are used as a base under floors.

Joist – beam that supports the floor

Marine Ply – type of plywood meant to be set beneath bathroom flooring to give an even surface to prevent tile cracking and prevent moisure collecting

Oversite – rough concrete below timber ground floors.

Screed – the top layer poured over insulation or concrete to which floor finishes can be applied

Sub-Soil – soil lying immediately below the topsoil.

Fireplaces, Chimneys and Flues

Balanced Flue– common flue type normally serving gas appliances, which allows air to be drawn to the appliance whilst also allowing fumes to escape.

Flue–   smoke duct in a chimney, or a proprietary pipe serving a heat producing appliance such as a central heating boiler or wood burning stove.

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. Other proprietary flue liners are also available.

Solid Fuel– heating fuel, normally wood, coal or one of a variety of proprietary fuels.

Built in Fittings

Mastic– a permanently flexible waterproofing material mostly used for sealing external or water-vulnerable joints in building or glazing etc.

Ventilation– necessary in all buildings to disperse moisture resulting from bathing, cooking, breathing etc., and to assist in prevention of condensation.

Woodwork, Joinery & Staircases

Architrave–  a moulding around a doorway or window opening. It usually covers the joints between the frame and the wall finish, thus hiding any shrinkage gaps, which may occur.

Bakelite door furniture/ironmongery– typical 1930s original door andle and surround (known to sometimes contain an element of asbestos)

Baluster–   a post or vertical pillar supporting a handrail or parapet rail.

Balustrade–  a collective name for a row of balusters or other infilling below a handrail on a stair or parapet.

Bressumer–  A lintel, often timber, over a shop front, fireplace or bay opening.

Carriage– A substantial timber that runs along the underside of a staircase.

Chipboard–  Chips of wood compressed and glued into sheet form. Cheap method of decking to flat roofs and floors

Dado Rail–   a moulding fixed to the wall or capping panelling and forming the top most part of a dado.

Going– staircase measurement of the horizontal distance between the front of one step to the front of the next step

Jamb– side post or surface of a door, window or fireplace

Joinery – wooden components of a building e.g stairs and timber doors

Lap joint– A joint formed between two components, where one overlaps another

Newel – vertical member of timber into which the diagonal strings of a stair can be fixed

Nosing– overhang or prominent part of a projection on stairs

Pelmet– narrow cloth or wood border across the top of a door or window to coneal curtain fittings etc.

Plywood– board made from veneers of wood glued with the grain laid at right angles.

Reveals– the side faces of a window or door opening.


  1. Vertical face at the back of a step
  2. Vertical service duct, pipe or cable for services, e.g. water, gas, electric

Spandrel– panelling above and to the sides of an arch; also, the space below a staircase.

Spindle– a balluster. Often a decorative series of timbers infilling between the bannister and stairs.

String– the sides of a staircase. The one fixed to the wall is the ‘wall string’; the other is the ‘outer string’.

Tread– horizontal part of a step or stair.

Bathroom Fittings

Durgo Valve– a type of air admittance valve used as an alternative to a soil vent pipe. A one way valve that allows air to enter into a plumbing drainage system if there is negative pressure.

Macerator– an electrical device attached to a WC that shreds and pumps away the waste. This enables the use of small diameter waste pipes and enables the fitting of a WC in locations away from soil pipes or in basements.


Conduit– usually a metal or plastic tube used to protect electrical cables.

Consumer Unit (distribution board)– fuses or circuit breakers providing short circuit protection to an electrical system.

Intumescent light covers– fire proof covers for spotlights required by current Building Regulations

MCB – Minitature circuit breakers

Plant – Mechanical equipment and services e.g. cranes and excavators or substations and refineries

RCD– Residual Current Device

Gas / Oil

Bund – a wall used to prevent leaking from an oil tank

LPG– liquid Petroleum Gas or Propane. Available to serve gas appliances in areas without mains gas. Requires a correctly positioned storage tank or bottles.


Ball Valve (Ballcock)–  valve operated by a ball floating in a cistern.

Foul Water – Another term for waste water

Stopcock– a valve on a gas or water supply pipe which is used to cut off the supply

Surface Water– another term for rainwater. 


Expansion tank– tank in loft used to fill radiators with hot water

Microbore pipework– very small pipeowrk diameter, typically 6-12mm. Flexible copper material used in central heating systems to enable pipework to run through walls and under floors

Water Heating

Lagging– 1. Thermal insulation for hot surfaces to prevent heat loss 


Benching– shaped concrete slope beside drainage channel within an inspection chamber.

Cesspool (cesspit)– a simple method of drainage comprising a holding tank, which needs frequent emptying. Not to be confused with a “septic tank” which treats waste.

Drains– 3 types of drainage chanel:

  1. Vitrified clay
  2. Fibre cement (typically 1950s or 60s)
  3. PVC

French Drain– a gravel filled drainage trench, typically constructed against a wall. Can be a cost-effective way of reducing damp caused by high ground levels without the need for extensive removal of paths/hardstanding.

Inspection Chamber– commonly called the “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.

Rodding Eye– An opening in a drain or ventilation pipe, covered by a plate, the removal of which allows the drain to be rodded to clear blockages.

Septic Tank–  private drain installation whereby sewage decomposes through the action of bacteria, which can be slowed down or stopped altogether by the over use of chemicals such as bleach, biological washing powders etc.

Sewer– a large, underground pipe or drain used for conveying waste water and sewage. The Local Authority is usually responsible for the sewers, which collect the effluent from various drains, the drains being the responsibility of the land owners.

Soakaway– a pit, filled with broken stones etc. below ground to take drainage from rainwater pipes or land drains and allow it to disperse.

Soil Pipe/Soil Stack– a vertical pipe conveys sewage to the drains. Its upper end it usually vented above the eaves.

Trap– a ‘U’ shaped bend in a waste pipe, soil pipe or gulley containing enough water to provide a seal and prevent the ingress of foul air into a building.

Waste Pipe– a pipe usually carrying water away from a basin, bath or sink.


Coping– The top of a brick or stone wall, typicaly curved or sloping

Edging bricks– bricks used to create borders for patios

Folly/Follies– A costly ornamental building with no practical purpose e.g. a tower or mock gothic ruin in a park or garden

Random Rubble– basic early method of stone wall construction with no attempt at bonding or coursing.


Asbestos – Mined, naturally occuring fibrous mineral silicate. Has excellent fire proofing qualities and blends well with other materials. Three types, Brown, Blue and White (the latter most commonly found today) Used in lagging, asbestos insulation boarding, thermo plastic floor tiles, corrugated roofs on garages, blended into roof tiles and used in ‘Artex texture ceilings to name a few. Considered a deleterious material since 1985 and banned as a building material since 1999.

Carbonation– chemical process occuring when carbon dioxide is dissolved in water or an aqueous solution. Harmful for many materials as it usually causes a decrease in strength – seen in steel within reinforced concrete.

Cavity wall tie failure– failure of galvanised material to prevent rust. Metal rusts and expands exerting pressure on the outer leaf of a cavity wall

Chemical Attack – expansion and progressive disintigration of cement products occurs when mortar, render or concrete come into contact with soluble sulphates found in clay bricks, the ground or infil material.

Chimney Defects

  • Horizontal and Vertical Cracking
  • Leaning, often from washed out pointing to one elevation or expansion of mortar joints due to chemical reactions
  • Bulging stack from damaged flaunchings or expansion from inadequate flue liner
  • Heavy attachments such as aerials effecting stabiity
  • Broken or loose chimney pots
  • Spalling brickwork from frost damage or exposure to elements over time
  • Damaged flaunchings
  • Heavy moss or lichen covering abosrbing moisture into the brick/stonework

Cold Bridging– An area of building fabric that has higher thermal transmission than the surrounding parts of the fabric – results in reduction in overall thermal insulation, which can lead to greater risk of condensation and forming of mould

Condensation– common in modern properties and caused when warm moist air cools to a temperature where it can no longer hold water. Symptoms include surface mould, water residue on windows which can lead to timber decay. Occurs in areas with poor ventilation

Creep – permanent deformation of materials that takes place usually at elevated temperatures, especially in metals. Creep in conrete occuers at ambient temperatures

Cut edge corrosion– common form of corosion at the edge of galvanised steel where the cross section of the paint coated metal is exposed to the environment

Delamination– a type of failure whereby one of the layers in a masonry wall or roof tile separate from the surface

Dry rot– a fungal attack on timber that occurs in wood with a high moisture content (normally around 22%)

Efflorescence– a white mark on brick walls caused by evaporation of water causing sulphates in bricks to be brought to the surface.

Flooding– Flooding can occur for a number of reasons, including a nearby overflowing water course, surface water flooding, blocked or leaking drains or a damaged appliance. Flood prevention methods should be implemented if your dwelling is considered to be in an area at high risk of flooding. The Environmental Agency and the Government Flood Warning Information service can give you an indication, though you should seek Flood specific searches and Environmental searches through your legal advisor on purchasing a new property.

Giant Hogweed– An invasive and large plant that has been identified as a public health hazard. Laws prohibiting its growth and proliferation are in force in many countries. It can grow to heights of six metres and its sap is highly caustic when exposed to sunlight, leaving severe burns that can have long-term effects.

Heave – upward movement of ground supporting the building. Takes many years to occur and mainly precipitated by the removal of nearby trees

Interstitial Condensation– warm moist air penetrates inside a wall, roof or floor structure, reaches dew point and condenses into liquid causing damage.

Japanese Knotweed– A plant which can damage hard surfaces such as tarmac, grow through the floors of houses, occasionally even through the foundations. It is an offence in the UK to cause this plant to grow in the wild under the 1981 Wildlife and Countryside Act, and any waste material, such as that arising from cutting, mowing or excavation, needs to be disposed of in accordance with the Environmental Protection Act 1990 (Duty of Care) Regulations.

Krypto Efflorescene –salts trapped behind the smooth face of bricks expand when wetted by rain and cause the face of the bricks to crumble and disintegrate

Landslip – movement of ground mass down an incline or slope to find a natural level. Usually brought on by an 8% increase in natural water content or leaking pipes

Lead Paint– Lead can seriously damage human health, whether ingested or inhaled. Properties built before the 1970’s, and where paint layers are thick, are most likely to contain lead paint.

Mortar/Mason Bees– Species of bee that nest in crevices or holes in masonry. Females use naturally-occurring holes in either the bricks themselves or the mortar joints. The most effective method of preventing further damage is the re-pointing of affected areas.

Mundic – Deterioration in concrete due to decomposition of mineral constituents within the aggregate

Penetrating damp– mainly caused by leaking pipes, flooding or inadequate barriers such as damaged damp proof courses, flashings etc. signs include cracks, staining and damp walls, eroded/washed out mortar joints and shrinkage of building materials

Plastic Creep/deformation– Long term exposure to high levels of stress can cause permanent or non-recoverable deformation after release of the applied load. Seen on uPVC windows that replaced original windows where support not adequate.

Radon – Radon is a natural radioactive gas, originating from uranium which occurs in many types of rock.

Ragwort – A yellow-flowered ragged-leaved common weed, which is common on grazing land and is toxic to livestock.

Rising Damp– mainly caused by ground moisture which draws up salts from the soil and works its way through walls. Common where the water table is high, signs include white crusty residue on the face of wall plaster, blistering paint finishes and peeling wallpaper.

Roof Defects

  • Rotten and deteriorated roof timbers
  • Poor materials and workmanship from previous repairs
  • Inadequately designed or poorly constucted loft conversions or other alterations
  • Inadequately sized or insufficient structural members in older buildings
  • Heavier replacement roof coverings causing overloading of roof structure
  • Wood boring insect attack
  • Overloading and cracking of internal supporting walls in loft conversions
  • Overloading of ceiling joists from storage of heavy items in a loft space
  • Unsupported chimney stacks or water tanks
  • Inadequate bracing along the length of a roof and/or restraint of gable walls
  • Insulation preventing ventilation
  • Inadequate pitch to roof to suit roof covering material
  • Flat roof deterioration
  • Ripped underfelt and cracked tiles allowing water into the roof space
  • Condensation damage to underfelt and timbers, particularly on northerly elevations
  • Roof Spread – deformation of the roof profile at the ridge or on the slope. Signs of roof spread include walls bowing or cracks appearing at eaves level. Caused by weak rafters that are either poorly designed or not triangulated with or fixed to the ceiling joists

Spalling– Defect in walls where concrete, stone or brick breaks away from the main structure due to frost attack, aggregate or material expansion and contraction. Caused by moisture or thermal movement.

Structural movement (other causes)

  • Settlement after construction
  • Thermal expansion and contraction
  • Chemical attack
  • Roof spread
  • Wall tie failure

Subsidence – vertical downward movement of a buildings foundation caused by loss of support to the ground beneath the foundations. There are many causes of structural movement, but ‘true’ subsidence is mainly caused by soil shrinkage in clay or silt soils or man mande instability, such as mining or quarrys. The proximity to trees can be a contributing factor, as can leaking drains.

Sulphate Attack– chemical reaction, activated by water, between tricalcium aluminate and soluble sulphates which can cause deterioration in brick walls and concrete floors.

Wet Rot– a decay affecting timber cause by alternative wetting and drying

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