Building Terms Glossary

Also: plumbed ice maker, ice dispenser, ice and water dispenser

A feature of American-style fridge-freezers that requires a dedicated 15mm cold water supply pipe routed to the fridge location. Must be planned at first-fix plumbing stage — after the floor is screeded there is no practical retrofit route.

Also: IKEA kitchen planning service, IKEA kitchen measuring service, IKEA Kitchen Planner

The most widely-used kitchen planning tool in the UK consumer market. Offers a free online Kitchen Planner and a £35 professional measuring service (technician home visit, dimensions loaded into planner within 24 hours).

A cordless driver that uses rotational impacts to drive screws and bolts with much more torque than a combi drill. Ideal for driving long screws into timber, coach bolts, and any heavy-duty fixing work. Not suitable for drilling holes.

Also: highway impact, traffic generation

A material planning consideration where a proposed development would increase vehicle movements, affecting road safety or residential amenity.

Also: IGT, independent gas network

A private network operator that owns gas distribution pipes on newer housing developments. IGTs are not subject to the same regulated pricing structure as the four main Gas Distribution Networks (Cadent, SGN, NGN, WWU). Meter relocation costs on an IGT network can be dramatically higher — sometimes five to ten times the equivalent GDN rate. Check your gas bill or use a postcode checker to confirm whether your property is served by an IGT before requesting a meter relocation quote.

Also: DIY Kitchens, Howdens trade, Howdens, DIY Kitchens online, Benchmarx

Suppliers offering kitchen units and worktops at lower cost, often without design services or as trade-only

Also: induction cooktop, induction cooker

A hob that uses electromagnetic induction to heat compatible (ferromagnetic) cookware. Requires a dedicated 32A circuit with 6mm² cable minimum; hobs over 7.4kW need a 40A circuit with 10mm² cable. Energy efficient and precise but requires compatible pans.

Also: infrared stripper, IR paint stripper, Speedheater, Spengar infrared stripper

A panel-based tool that uses infrared radiation to soften paint film without vaporising lead. Surface temperature stays well below 500°C, making it the recommended method for stripping paint from pre-1970 properties where lead paint is likely. Slower than a heat gun but safer for lead-paint scenarios. Entry-level units (Spengar) cost around £75; professional Speedheater units range £150–300.

Also: insolvent, company insolvency, supplier insolvency, contractor insolvency

When a company can no longer pay its debts as they fall due. If your builder becomes insolvent, your contract is effectively at an end and recovering money you’ve paid will be difficult.

Also: SI 2016/1024, Insolvency Rules 2016, Rule 14.4

The rules governing how insolvency proceedings work in England and Wales, relevant if your builder becomes insolvent during your project.

Also: IP, administrator, liquidator, office holder, receiver

Licensed professional appointed to manage a formal insolvency process — as administrator, liquidator, or receiver. Sends the first formal letter homeowners receive when a supplier enters insolvency.

Also: the Insolvency Service, insolvencydirect.bis.gov.uk, Official Receiver

The government agency that deals with company and personal insolvency in England and Wales. Contact them if your builder’s company goes into liquidation.

Also: early signs of insolvency, supplier financial distress signals, pre-insolvency red flags

Red flags that a builder may be in financial trouble, such as asking for large upfront payments, paying subcontractors late, materials not arriving, or workers disappearing from site.

Also: manhole, drain access chamber, access chamber, inspection chambers

An access point in a drainage run that allows inspection, testing, and clearing of blockages. Building control checks that inspection chambers are positioned at junctions, changes of direction, and at intervals along longer runs.

Also: stage notification list, BC inspection schedule, inspection schedule

The document issued by the building control body when a Full Plans application is approved, listing all inspection stages they will require notification for — typically foundations, oversite, drainage, DPC, structural beams, insulation, and completion.

Also: LED torch, work light, inspection light, site torch

A handheld torch used during snagging inspections to illuminate corners, low-light areas, behind doors, and under units where overhead lighting is insufficient to reveal surface defects in plaster, paint, and tiling.

Also: ICE, ice.org.uk

Professional body for civil engineers in the UK. ICE membership (alongside IStructE) is a key credential for structural engineers. Provides a Find a Member directory for homeowners.

Also: IStructE, istructe.org

The professional body for structural engineers in the UK. Provides a Find an Engineer directory for homeowners to verify SE credentials.

Also: thermal board, insulated drylining, Kingspan Kooltherm, Celotex PL board, Kingspan K118, Celotex PL4000, Gyproc ThermaLine PIR

Plasterboard factory-bonded to a layer of PIR insulation. Provides insulation and a plaster-ready surface in one product. Used for internal wall insulation, particularly on solid masonry walls where cavity insulation is not possible.

Also: IGU, double glazed unit, DGU, sealed unit, triple glazed unit, TGU

Sealed glass assemblies within bifold and sliding door frames. NHBC Standards require drained and vented glazing systems for site-fixed IGUs and dual-seal construction for units greater than 1m².

Thermal insulation products used in walls, roofs, floors and around openings to meet Building Regulations Part L energy efficiency requirements.

Also: kPa rating, compressive strength

The kPa rating determining which insulation board grade is safe under load. Floor-grade PIR requires minimum 120-140 kPa. Wall-grade at 100 kPa will compress and fail under screed weight.

Also: IR test, first-stage insulation test, Regulation 643.3.2 test

The first-stage insulation resistance test mandated by BS 7671 Amendment 2 (Regulation 643.3.2) that must be carried out at first-fix stage before walls are closed up. Confirms cable insulation integrity before plasterboard goes on.

Also: built-in appliance, fully integrated appliance, semi-integrated appliance

A kitchen appliance designed to be concealed behind a door panel matching the rest of the kitchen units. Requires housing units specified at the kitchen design stage with exact dimensions. Integrated fridges/freezers are internally smaller than freestanding equivalents. Replacing requires matching door split and dimensions.

Also: integral blinds, built-in blinds, between-glass blinds, in-glass blinds

Blinds sealed between glass panes in bifold or sliding door panels. Cost £3,600-£7,000 for 3-4 panel systems. Critical downside: failure requires replacing the entire glass unit, not just the blind mechanism.

Also: condensation within insulation

Condensation occurring within a building element when warm moist air penetrates an incomplete vapour control layer and meets a cold surface. Primary failure mode of poorly installed PIR insulation.

Also: fire protection coating, intumescent paint, steel fire protection

A specialist paint applied to structural steel beams that expands when heated to form an insulating char, protecting the steel from fire. Required under Building Regulations Part B for steel beams in certain exposed positions.

Also: fire door seal, intumescent seal

Rubber or graphite seal fitted into a groove in fire door frames. Expands when exposed to heat, sealing the gap between door and frame to prevent fire and smoke spread. Required for FD30 fire door assemblies.

Also: invert, IL, pipe invert

The level of the lowest point of the internal surface of a drainage pipe at any given location. Used to calculate gradients and verify that a new drainage connection to an existing system can achieve adequate fall. A CCTV drain survey or physical dip of the existing manhole reveals the invert level at the connection point, which is the starting measurement for gradient calculations back to the extension.

Also: ITT, tender invitation, tender letter

A formal package sent to builders inviting them to quote for your project, typically including drawings, specifications and a deadline for responses.

Also: Ingress Protection rating, IP65, IP66, weatherproof rating

The Ingress Protection rating system specifying a fitting's resistance to water and dust. Outdoor sockets require minimum IP66; outdoor lighting minimum IP65.

Also: service valve, isolating valve, quarter-turn valve, ball valve

A valve fitted to each appliance or fixture supply pipe allowing that single point to be shut off without affecting the rest of the house.