Building Terms Glossary

Also: ear muffs, hearing protection

Over-ear hearing protection for use with loud power tools such as angle grinders, SDS drills, and circular saws. Prolonged exposure to power tool noise causes permanent hearing damage. Look for an SNR (Single Number Rating) of at least 25dB.

Also: green/yellow sleeving, CPC sleeving, earth sleeve, green and yellow sleeve

The green/yellow PVC sleeve that must cover the bare copper CPC (earth conductor) of twin-and-earth cable at every exposed termination point. Failure to sleeve the bare earth is the most common first fix mistake.

Also: green/yellow earth sleeve, CPC sleeving, earth conductor sleeve, green yellow sleeve

Green/yellow PVC tube slipped over the bare copper CPC at every termination point in twin-and-earth cable installations. Sold in rolls. Essential consumable for first fix electrics.

The point where the external wall of a building meets the underside of the roof. On a pitched roof, the eaves are at the bottom edge where the roof overhangs the wall. On a flat roof, the eaves are at the top of the wall where the roof starts. Eaves height is a key measurement for permitted development compliance.

Also: eaves

The height measured from ground level to the point where the external wall meets the roof structure. Under PD rules for extensions, eaves height must not exceed 3 metres within 2 metres of a boundary, and must not exceed the eaves height of the existing house.

Also: underlay support tray, eaves tray, membrane support tray, eaves carrier tray

Also: white marks on roof tiles, calcium deposits on tiles

The thread type on which PTFE tape provides no sealing. Parallel threads seal on a flat-face washer or O-ring seated in the fitting, not on the thread engagement.

Also: escape window, means of escape window, fire escape window

Openable window meeting Part B minimum dimensions (450mm clear opening, 0.33m² area, sill max 1100mm from floor) required in habitable rooms as a means of fire escape.

Also: Electrical Installation Condition Report, electrical condition report, electrical inspection, periodic inspection report

A formal inspection and test of an existing electrical installation, producing a condition report before new work is undertaken. Recommended before replacing or upgrading a consumer unit to identify pre-existing faults.

Also: Electrical Contractors' Association self-certification scheme

UK competent person scheme for electrical work alongside NICEIC and NAPIT. ELECSA-registered electricians can self-certify Part P notifiable work without a separate building control application.

Also: wet tile saw

A powered wet-cutting saw with a diamond blade for precision cuts through ceramic, porcelain, and natural stone tiles. Water keeps the blade cool and suppresses dust. Essential for L-shaped cuts, notches, and thick porcelain tiles.

Also: EESR 2016

UK statutory instrument (SI 2016/1101) governing the safety of all electrical equipment placed on the UK market, including kitchen appliances. Distinct from Part P which covers installation — EESR covers the appliance design and manufacture safety requirements.

Also: electrical completion documentation, Part P handover documents, electrical certification pack

Full documentation bundle from electrical work completion: EIC, Part P notification certificate, circuit schedule, and product warranties. Required for building control sign-off, insurance claims, and house sales.

Also: EIC, electrical completion certificate, Part P certificate

The formal certificate issued by a qualified electrician on completion of new electrical work, confirming the installation has been designed, constructed, inspected, and tested in accordance with BS 7671. Required by building control before issuing a completion certificate.

Also: electrical plan, socket layout plan, wiring layout plan, electrical floor plan

A scaled floor plan marked with socket, switch, and lighting positions that the homeowner prepares before meeting the electrician. Its absence causes the most common first fix mistake: sockets in wrong positions.

Also: electrical supplies, wiring supplies

Cables, consumer units, protective devices, back boxes, faceplates and conduit used in domestic electrical installations. All electrical work in extensions must comply with Part P of the Building Regulations and be certified by a registered electrician.

Tools for testing, preparing, and connecting electrical cables and fittings. Note: electrical work on an extension must be done or certified by a Part P qualified electrician, but understanding the tools helps you communicate with your electrician and do minor tasks.

Also: CEF, Edmundson

Trade wholesalers supplying cable, consumer units, sockets, switches, and lighting

Also: sparky

Installs and certifies electrical wiring, consumer units, lighting, and sockets

Also: EaWR 1989, Electricity at Work Regulations

Primary UK statutory instrument governing electrical safety at work. Legal basis for HSE GS38 guidance on test equipment.

Also: ELI, employers liability

Legally required insurance for any builder who employs staff, covering employees injured at work. A builder with workers who lacks this insurance is operating illegally.

Also: matt emulsion, silk emulsion, wall paint, ceiling paint

Water-based paint for internal walls and ceilings. Matt finish hides imperfections better and is preferred for ceilings and most walls. Silk or eggshell finishes are more wipeable and suited to kitchens, hallways and children's rooms. Two coats over a primed surface is standard.

Also: EN 14404, BS EN 14404

Knee protector standard defining types and performance levels. 2024 revision introduced mandatory garment certification for trouser-pocket pads.

Also: EN 149, BS EN 149

European standard defining FFP1, FFP2, and FFP3 dust mask filtration classes. CE marking under this standard is required for all dust masks used as workplace PPE.

Also: EN 166, BS EN 166

European standard for personal eye protection. Defines impact ratings, optical classes, and lens treatment codes. Being superseded by EN ISO 16321 but remains valid until October 2029.

Also: BS EN 352

European standard for hearing protectors covering earmuffs, earplugs, and helmet-attached defenders.

Also: EN 374, BS EN 374

Standard for protective gloves against chemicals. HSE requires EN 374-certified gloves for cement and concrete work due to high alkalinity.

Also: EN 388, BS EN 388

Standard for protective gloves against mechanical risks. Five-position rating code for abrasion, cut, tear, puncture, and straight-blade cut resistance.

Also: BS EN 397, EN 397:2012+A1:2012

European standard for industrial safety helmets. Tests crown impact, penetration resistance, chin strap release, and flame resistance. Required for construction site hard hats in the UK.

Also: EN ISO 20345, BS EN ISO 20345, EN ISO 20345:2022+A1:2024

Safety footwear standard. Defines S1-S7 classifications. S3 is the construction site minimum with steel toecap, midsole protection, and water resistance.

Also: BS EN ISO 20471, EN ISO 20471:2013

High-visibility clothing standard. Defines Class 1-3 by fluorescent material area. Class 2 is the construction site minimum.

Also: plywood grades, WBP classification

The modern European standard replacing the obsolete WBP terminology for plywood. EN636-1 is dry conditions, EN636-2 is humid conditions, EN636-3 is exterior. The trade still uses 'WBP' colloquially but it has had no official meaning since 1995.

Also: cut end preservative, end grain preserver

Brush-on preservative for re-sealing cut ends of treated timber. Factory treatment only penetrates a few mm; cutting exposes bare wood that must be re-treated. Apply two coats minimum. Barrettine is the most common UK brand.

Also: ENA, energynetworks.org, postcode lookup for network operator

Operates the postcode lookup tool for identifying which Gas Distribution Network and electricity Distribution Network Operator serves an address.

Also: EPC, energy certificate, SAP EPC

Document issued to a property showing its energy efficiency rating (A–G). Required to be lodged for extensions over 25% of existing floor area. Produced by an accredited energy assessor from the as-built SAP assessment. Distinct from the SAP assessment itself — homeowners frequently confuse the two.

Also: EU energy label, appliance energy label, A-G energy rating, energy efficiency rating

The UK/EU energy rating scale for appliances changed on 1 March 2021 from A+++ to D to a simpler A-G scale. Most new appliances now sit B–D; A-rated models are rare and command a premium. Understanding the difference is necessary for accurate appliance comparison.

Also: gas supplier, electricity supplier, British Gas, OVO Energy, Octopus Energy, EDF

The energy supplier is distinct from the GDN and DNO. Only the current supplier can move the meter itself. Delays from the energy supplier are the most common cause of extreme meter relocation timelines.

A formal notice issued by the local council requiring unauthorised development to be reversed. Can require demolition of the work and restoration of the site to its original state, at the homeowner's expense with no compensation.

Also: engineered oak, engineered hardwood, engineered timber floor, click engineered wood

A floor covering with a real wood veneer over a plywood or HDF core. Works with UFH (unlike solid timber) but is more susceptible to moisture damage than tiles or LVT. Screed moisture must be tested to 65% RH (stricter than the 75% threshold for LVT/tiles) before installation.

Also: Class A engineering bricks, Class B engineering bricks, blue engineering bricks

High-strength, low-porosity bricks used below DPC level, in manholes, and wherever moisture resistance is critical. Class A is stronger and more expensive than Class B; Class B is sufficient for most domestic extension work.

Also: EA, gov.uk/environment-agency

UK government body that regulates waste management, issues waste carrier licences, and publishes guidance on waste classification including the plasterboard co-disposal ban

Also: impact adhesive, EPDM perimeter adhesive, solvent-based EPDM adhesive

Also: EPDM, rubber roof, Firestone EPDM, ClassicBond, Hertalan, RubberBond FleeceBack, Carlisle SynTec, RubberCover

Single-ply rubber membrane for flat roofs. Excellent lifespan (30-50 years), flexible and easy to install as a single sheet without joints. The preferred flat roof covering for extensions. Requires a clean, smooth substrate (typically OSB or plywood deck).

Also: EPDM cover strip tape, seam cover tape, 3-inch seam tape, 6-inch seam tape

Also: water-based adhesive, EPDM deck adhesive, low-VOC EPDM adhesive

Also: polystyrene insulation, Jablite, EPS boards, Jabfloor 70, EPS70

Lightweight, rigid expanded polystyrene insulation boards. Lower thermal performance per mm than PIR but significantly cheaper. Commonly used below floor slabs and in less thermally demanding applications.

Also: Euroclass rating, BS EN 13501-1 classification, reaction to fire classification

European reaction-to-fire classification under BS EN 13501-1, ranking products from A1 (non-combustible) through E (limited contribution) and F (untested or worst case). Smoke (s1-s3) and flaming droplets (d0-d2) sub-classifications follow the main letter. Used in Approved Document B to determine where a material may be installed.

Also: Euroclass, BS EN 13501-1

European fire classification system for construction products. PIR is Euroclass E/F (combustible, legal under 11m). Mineral wool is Euroclass A1 (non-combustible).

Also: movement joint, control joint, blockwork expansion joint, screed expansion joint

A deliberate gap in blockwork filled with compressible material to accommodate thermal expansion and contraction. Required at 6-metre centres for concrete blockwork and 12-metre centres for brickwork per NHBC standards. Missing expansion joints are a common building defect.

Also: EoT, agreed time extension

A mutual agreement between an applicant and the local planning authority to extend the statutory determination period beyond 8 weeks, allowing time for negotiations or amended plans.

Also: hard landscaping, soft landscaping, external reinstatement, landscaping materials

Paving, turf, topsoil, and fencing materials for the outside reinstatement work that follows an extension — the jobs that finish the build visually and which builders' quotes often omit.

Also: extract rate, air flow rate, extraction capacity, l/s rating, m3/h rating, litres per second

The measure of how much air a cooker hood removes per second (l/s) or per hour (m³/h). Approved Document F specifies minimum extraction rates: 30 l/s when adjacent to the hob, or 60 l/s when located elsewhere in the room.