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This Glossary can be downloaded in pdf format here: Glossary of Building Terms.


Absolute – The guarantee of title to ownership.

Administration Fee – A payment to cover the costs of processing a property guarantee transfer of paperwork or alternatively arranging back-up insurance.

Air Brick – A perforated brick used for ventilation, usually under timber floors and in roof spaces. Examples of its use are to ventilate the underside of timber ground floors, blocked fireplaces or a roof space.

Annual Percentage Rate (APR) – The total cost of a loan, considering interest charges, arrangement fees and other costs, shown as a percentage.

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

Asbestos – A potential serous health hazard. If you suspect your insulation may use this fibrous mineral, seek specialist advice immediately.

Asbestos Cement – Cement mixed with up to 15% asbestos fibre as reinforcement. Typically used in roofing, rainwater goods, fire-proof linings and various other claddings and linings. Hazardous fibres may be released if cut or drilled. Again, specialist advice should be sought.

Asphalt – Used on floors and flat roofs, this black, tar like substance is waterproof and very sticky.

Assign – To transfer the right or interest in a property from one person to another.

Assignee – The person to whom the right or interest of property is transferred.

Assignor – The person who transfers a right or interest of property to another person.


Back Gutter – The lining and flashing arrangement at the back of a chimney stack (on the upslope side) to divert rainwater away from the stack.

Bargeboard – Timber, sometimes decorative, placed along the verge of a roof at a gable end.

Balanced Flue – A room sealed pipe or tube fitted to a gas appliance that lets the fumes escape.

Balustrade – A row of balusters, or other infilling, below a handrail on a landing, stair or parapet.

Bark Borer – (Ernobius Mollis) Normally found in soft woods in dead trees or dry timber in buildings if bark is present.  Insecticide treatment is not necessary where this is found in buildings.

Base Rate – The rate of interest that the Bank of England charges for lending to other banks. These banks then use it as a benchmark for the interest rates they charge when lending money to consumers, often stipulating an interest rate ‘X% above the base rate’

Batten – Thin strips of timber, commonly used to support roof tiles or slates.

Bellcast – Thickening out of render, in a curved shape, to form a drip to deflect water. This is usually found at the base of a wall, above the damp-proof course.

Bitumen – Black, sticky substance, like asphalt. Used in sealants, mineral felts and damp-proof courses.

Brace – Diagonal support in a timber door.

Bracing –Timbers spanning across roof trusses to provide lateral stability.

Breach of Contract – Where one of the parties bound by a contract fails to keep to the other contract’s terms and conditions.

Breeze Block – A building block made from concrete and cement

Bressumer – A lintel, often timber, over an opening such as a fireplace or bay.

BS8102:2022 – Code of Practice for protection of below ground structures against water from the ground.

Building Survey – A full inspection of a property and a report on its condition, highlighting any problems and work that will be needed.

Buttress – A brick or stone support to a wall designed to resist lateral movement.


Capillary Moisture – Moisture held in the capillaries of a material and which exerts no positive pressure on the structure.

Capping – The weather-proof finish formed with tiles or stone or concrete copings, over a wall parapet or chimney.

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

Cavity Tray – A moisture barrier inserted above a window or door opening to deflect moisture that transfers across the outer leaf of brickwork back to the outer face rather than letting it cross the cavity at lintel level causing dampness internally.

Cavity Wall – An external wall which has been constructed with a gap of about 50mm (2 inches) between the 2 leaves of brick or block work.

Cavity Wall Insulation – Insulated material used to fill the cavity wall – usually polystyrene beads, foam or rockwool.

CDM (Cavity Drain Membrane) –  Dimpled, flexible, high density polyethylene (HDPE) or polypropylene sheets which are placed against the internal face of the structure and used to control infiltrating water.

Cellar Fungus (Also known as Wet Rot and Coniophora Puteana) – This is the most common of the Wet Rot species and causes decay normally associated by water damage, damp/condensation.

Cement Fillet – A weatherproofing joint between roof slopes and abutting brickwork such as walls or chimneys.

Chase – To cut into plaster, brickwork etc to receive cables and pipes.

Chipboard – Chips of wood compressed and glued into sheet form. Cheap method of decking to flat roofs, floors and (with Formica and melamine surfaces) furniture and kitchen units.

Cleared Funds – Money that is available instantly without clearing through the banking system. This is usually cash, bank automated credit or a banker’s draft.

Collar – A horizontal tie beam of a roof, which is joined to opposing rafters at a level above that of the wall plates, designed to restrain opposing roof slopes.

Combination Boiler – A type of boiler that give you heating and hot water on demand, without using hot and cold-water tanks.

Common Areas – The areas not owned by any individual lessee but shared by all owners in an apartment block or estate. They may include car parks, entrance halls, gardens, lifts and corridors.

Common Furniture Beetle (Anobium Punctatum) – These generally affect softwoods and European hardwood. Emergence holes are normally 1-2 mm in diameter mainly in the direction of the grain. Their life cycle is normally approximately 3 years.

Completion – The final stage or the legal work when the ownership of the property passes to the buyer.

Completion Date – The date that a contract takes effect and property ownership passes from seller to buyer.

Condensation – The process of which water transitions from a vapour into a liquid.

Contractual Obligation – A binding obligation imposed on parties in a contract which, if not complied with breaches the contract.

Coping/Coping Stone – Usually stone or concrete laid on top of a wall as a decorative finish and designed to stop rainwater soaking into the wall.

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

Cornice – A moulding at the junction between a wall and ceiling. Can also include a moulding at the top of an outside wall designed to project and throw raindrops clear of the wall.

Covenant – An agreement contained within a contract or a deed that binds somebody to do something (or not do something)

Coving – Curved junction between wall and ceiling i.e a type of cornice.

Cowl – A terminal to a flue pipe to aid discharge of gases and exclude the weather.

Crack Stitching – Repairs and stabilising cracked masonry by means of installing Helibars and specialist cementitious grouts.

Credit Check – A routine inquiry into a person’s borrowing and repayment history, usually performed by companies when reviewing an application for any form of credit.

Credit Rating – An aggregated assessment of a person’s credit history. The better your credit history, the better your credit rating and the more likely you are to be approved for loans.

Credit Report – The assessment of an individual’s credit history, usually compiled by a Credit Reference Agency and used by lenders to assess applications for credit.


Dado – The bottom one metre or so of wall clad with timber, originally designed to provide protection to the wall. The top edge is finished with a Dado Rail.

Damp-proof course (dpc) – A continuous physical or chemical barrier to prevent capillary movement of water in walls.

Death Watch Beetle (Xestobium Rufovillosum) – Found in hardwoods chiefly oak. May be heard and seen tapping their heads from March to June. Adult is 6 – 9mm.

Deed – A formal document of property ownership.

Deposit – The amount of money paid by the client prior to works commencing.

Dew Point – Temperature at which 100% relative humidity is reached and air becomes saturated with vapour (condenses).

Dormer – A construction with a window that projects from a sloping roof.

Dry Rot (Serpula Lacrymans) – A fungus that can cause serious damage to a property by attacking structural timbers. Flourishes in moist, damp, poorly ventilated areas, which is able to grow through masonry.

Due Diligence – A process of performing duties to a professional standard.

Duty of Care – An obligation owed to others, to provide the correct advice and to ensure the wellbeing and safety of those who visit/carry out works to a property.


Easements – This is a term given to the rights a person may enjoy over another property such as drainage rights, access to a neighbour’s land to carry out maintenance on their own property.

Eaves – The lower edge of a roof.

Efflorescence – Powdery white salts (sulphates) crystallised on the surface of a wall as a result of moisture evaporation.

Emergence Period – Time of year during which adult wood boring insects develop and emerge from infested wood.

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

Entry Hole – Hole made by some adult insects to enter and lay eggs within the wood.


Fascia – A board fixed to the rafter ends along the roof eaves.

Fillet – A thin strip of wood, cement, slate etc used to fill a narrow joint.

Flanked wall – A side wall.

Flashing – A section of material (normally metal or cement) used to prevent water from penetrating a roof joint.

Flaunching – A mortar weathering on the top of a chimney stack surrounding the base of the chimney pots to throw off the rain and thus prevent it from saturating the stack.

Flue – A pipe or duct attached to an appliance to allow fumes to escape.

Flying Freehold – Part of a freehold that overhangs or underlies another e.g. a bedroom or balcony that overhangs a shared passageway.

Footings – Older, usually shallow, form or foundation of brick or stone

Foundations – An underground structure that supports a building or wall.

Free Lime – Calcium Hydroxide (free lime) is a soluble form of lime which is created by Portland Cement. Free lime is deposited on the new construction where water flow over cementitious materials.

Fruiting Body – Associated with Dry Rot. Pancake or bracket shaped, the centre is normally yellow when young but darkens to rusty red when it matures owing to spores.

FSA – Financial Services Authority


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

Ground Heave – The swelling of clay subsoil which has absorbed water. This can cause foundations to move upwards.

Gully – An opening into a drain, normally at ground level, which receives water from downpipes and wastepipes.

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


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

Header – A brick laid end on.

Homebuyer’s report or survey – A homebuyer’s survey includes more detail than a mortgage valuation but doesn’t include as much detail as a full structural survey. The report will tell you about any major problems with the building, the general condition of the parts of the building that are reasonably accessible and any suspected problems, like timber infestation or damp that might need specialist advice.

Hopper Head – An open funnel or hopper shaped head at the top of a rain or waste pipe to collect rainwater and/or waste from one or more pipes.

House Longhorn Beetle (Hylotropes Bajulus) – Common only in the South West of London, mainly Surrey and is sometimes referred to as Camberley Beetle. It can cause structural damage due to large oval exit tunnels 6 – 10mm

Hydrostatic Pressure – pressure created by a static head of water.

Hygroscopic – the ability to absorb moisture from the atmosphere.

Hygrosocopic salts – chlorides and nitrates which are generally deposited in walls as a result of rising / penetrating damp from the ground and which have the ability to absorb atmospheric moisture. Sometimes found on chimney breasts as a result of historic burning of fossil fuels.

Hypha – Microscopic thread which forms the vegetative part (mycelium) and the reproductive part (fruiting body) of a fungus.


Inactive – Infestation of wood in which no fungus is growing or insects are living.

In Situ – Describing work done in the place where it is finally required e.g. concrete may be pre-cast off site in sections which are later taken to the position where they are required, or it may be cast ‘in site’ on the site itself.

ISO:9001:2015 – Quality Management System; this is a set of standards for management practices. It is an internationally recognised standard that businesses and government use.

ISO:14001:2015 – Environmental Management System; this is a set of standards relating to environmental management, created to help companies minimise how their operations affect the environment.

Interstitial Condensation – Condensation occurring within the structure as opposed to surface condensation.


Joist – A timber or steel beam directly supporting a floor or ceiling.


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


Landslip – Movement of earth, clay etc downwards, because of heavy rain or a lack of soil stability.

Larva – Grub-like stage of an insect’s life cycle, or a fungus which is living but not growing. However, it is capable of further growth and damage if suitable conditions occur.

Lath – Any base for plasterwork; typically, thin wooden strips or expanded metal.

Lean-to – A structure, the sloping roof of which abuts a higher wall.

Lining – the wood finish to a window or door jamb.

Lintel – A horizontal structure beam found over a window or door opening.  Often lintels can be partially or completely hidden from view.


Managing Agent – A professional or company responsible under an agency agreement for the maintenance and management of a property.

Manhole – The ground level access point to a drain, with a removable cover. Also known as an inspection chamber.

Mansard – A roof made with slopes of different pitches, usually providing an upper floor of useable space within a roof structure.

Mastic – A generic term for any sealant used in the building process.

Matchboard – A board that has a groove cut into one edge and a tongue cut into the other so they fit tightly together.

MDF – Medium density fibreboard

Mezzanine – A floor between the ground and first floors, often accessed off a half landing.

Mortar – Mixture of sand, cement (or lime) and water used to join stones, blocks or bricks and for pointing and general filling.

Moulds – There are many types commonly Penicillium spp and Aspergillus spp. These normally appear on the surface of damp wood, plaster, wallpaper or paintwork.

Mullion – Vertical bar dividing individual lights in a window.

Mycelium – Normally associated with Dry Rot. White sheets or cotton wool like cushions with patches of lemon.


Newel – Post supporting a staircase handrail at top and bottom. Also, the central pillar of winding spiral staircase.

NHBC – National House Builder Council. The NHBC provide a 10-year insurance policy on the main structure of new properties.

Nominal Interest Rate – An Interest Rate that does not account for inflation.


Ogee – A specific shape where a concave arc flows into a convex arc. An ogee gutter has profile, is usually formed in cast iron, and is still very common in Victorian housing.

Oversite – A layer of concrete below a timber ground floor above the external ground level.

Owner Occupier – The person who owns the property who is, has been and will be living in the property as his sole or principle residence.


Pantile – A curved roof tile which hooks over adjoining tiles, typical in some 1930’s construction.

Parapet – Low wall along the edge of a roof or balcony or extending over the roof slopes above a party or gable wall.

Parapet Gutter – A gutter behind a parapet usually provided with a flexible metal or other impervious lining.

Party Wall – The wall which separates but is shared by adjoining properties.

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

Pitch – The angle of slope to a roof.

Planning Permission – Official consent/approval from a Local Authority for works undertaken on a property.

Plasterboard – A layer of plaster sandwiched between heavy paper. Widely used for walls and ceilings.

Plinth – The projecting base of a wall.

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

Pointing – Outer edge of mortar joint between bricks, stones etc

Powderpost Beetle (Lyctus Bronneus) Normally always originates in stack yards. Found in timber containing adequate starch.

Public Liability Insurance – An insurance policy that aims to protect members of the public who are injured or affected by an accident or occurrence.

Purlin – The horizontal beam supporting the rafters in a roof space.


Rafter – One of the sloping roof beams that form the shell of the roof.

Relative Humidity – The amount of water vapour contained within a given volume of air compared with the maximum amount of water that could be in the same body of air in the given temperature.

Rendering – The covering of cement or plaster on a wall (More detail under Specialist Rendering)

Retaining Wall – A wall built to hold back a bank of soil.

Retention – Where a lender, or main contractor, retains part of a loan, pending satisfactory completion of specified works.

Reveal – The side or top faces of a window or door opening.

Ridge – The highest part or apex of a roof where 2 slopes meet.

Ridge Tile – A specially shaped angular or half round tile for covering and making weather-tight the ridge of a roof.

Right of Way – The legal right to use a particular route or path, usually in order to gain access to a property.

Riser – The vertical part of a step or stair.

Rising Damp – Moisture in a wall that rises from the ground up through the bricks and mortar or a building by capillary action.

RSJ – Rolled Steel Joist

Rough Cast – A rough render finish to external walls.


Salts – Chlorides, Nitrates, Sulphates. These are soluble salts that can be found in the ground or within some building materials.

Sarking – Felt used as an underlining to a roof.

Sash – The frame of a window that holds the glass.

Screed – The final smooth finish of a floor, usually laid in cement or concrete (More detail under waterproofing)

Shiplap – Horizontal external boarding, usually timber or PVC.

Skeiling – The raked (angled) part of a ceiling sometimes found at the perimeter of a top floor room, being the plastered underside of the principal roof rafters. This occurs where the ceilings are set at a level higher than the tops of the external walls.

Slime Moulds – Group of fungi which feed on bacteria within wet wood but fruit on the surface of the wood.

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

Soffit – The underside of an arch, beam, staircase, eaves or other feature of a building.

Soldier Course – A horizontal course of bricks set on end over a window or door opening.

Spall – Splitting of masonry, tiles, concrete etc usually due to the freezing and expansion of trapped water (frost damage)

Specialist Render – Applied coats using sand: cement mix which include plasticisers or other approved additives.

Spores – Associated with Dry Rot may settle as a fine layer of reddish brown dust on surfaces.

Stretcher – A brick or block laid lengthways

String – The sloping board to which the steps of a staircase are attached.

String Course – A course of brickwork that projects beyond the face of an external wall

Structural Slab – Top of the concrete slab on which the vertical levels of the building are set out. Screeds or finished floors are above this level.

Structural Survey – A survey of the condition of a property conducted by a qualified surveyor, detailing whether or not the property is structurally sound, as well as any defects that may require work to be undertaken.

Strut – A support, usually to a purlin.

Stud Partition – A lightweight wall that has a timber frame and is lined with plasterboard.

Subsidence – What happens when the ground moves downwards.

Sub-soil – Soil lying immediately below the topsoil

Sump – Pump – A sump pump station is designed to collect ground water via perimeter drainage for below ground applications.


Tenant – The person(s), company or organisation who is entitled to occupy a property under the terms and conditions of a tenancy agreement.

Tender –  To invite bids for a project.

Tenure – The type of ownership, either freehold or leasehold.

Thorax – Middle section of an insect’s body carrying the legs, wing and wing covers.

Tie Bar – Metal bar passing through a wall, or walls, to brace a structure suffering from structural instability, normally lateral.

Tread – The horizontal part of a step or stair.

Truss – A prefabricated triangular framework of timbers used in most modern roof constructions.


Underpinning – Placing a stronger foundation underneath the weaker original one.

Utilities – These are normally electricity, gas and water and may be referred to as services which under most circumstances, the tenant is responsible for paying for.


Wall Plate – Timber normally fixed on top of a wall to receive floor joists or roof rafters

Wall Tie – Usually a piece of metal bedded into the inner and outer leaves of a cavity wall to provide a physical connection between the two.

Waterbar – A material inserted in a joint to prevent the passage of water.

Waterproofing – The application of materials that are impervious to water.

WDS – Waterproof Design Specialist Register.

Weatherboard – A board fixed externally to the bottom of a door to exclude driving rain.

Wet Rot – There are many species of Wet Rot. They cause the timber to darken (Brown Rot) or bleach (White Rot)

Woodworm – See Common Furniture Beetle

Woodboring Weevils (Euophryum Confine) – Normally found in decayed softwoods and hardwoods in damp conditions to ground floors.

The information contained in this glossary is given in good faith and is believed to be correct.  Preservation Treatments is therefore unable to accept responsibility for any loss arising from the use of this information provided.