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: ERC, mortgage ERC, early redemption penalty, redemption fee

A penalty charged by a mortgage lender when a borrower repays all or part of a mortgage before the end of a fixed-rate term. Often the deciding factor when choosing between a full remortgage and a further advance or second-charge loan — an ERC can make remortgage more expensive than a higher-headline-rate alternative.

Also: green/yellow 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.

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

A rigid plastic tray fixed over the fascia at the eaves to carry the roofing underlay out over the gutter. It stops the felt sagging and rotting and guides water into the gutter.

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: 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: EA waste carrier check, CBDU register, public register of waste carriers

Free publicly searchable register of licensed waste carriers, brokers, and dealers maintained by the Environment Agency. Upper-tier registrations start with the prefix CBDU. Homeowners should check their muck-away contractor's CBDU number on this register before allowing any waste to leave site; if the registration is absent or expired, the homeowner inherits the disposal liability.

Also: EPA 1990 s.34, waste duty of care legislation, Environmental Protection Act 1990

Primary UK legislation placing a duty of care on anyone who produces, carries, or disposes of controlled waste including excavation spoil. Requires use of a registered waste carrier, disposal only at authorised sites, and retention of a waste transfer note for at least two years. Failure makes the waste producer (the homeowner) jointly liable for any illegal disposal.

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

A solvent-based contact adhesive used to bond EPDM membrane at detailing points such as upstands, kerbs and vertical surfaces, where a stronger and faster grab than the water-based field adhesive is needed.

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

A double-sided tape used to join overlapping sheets of EPDM membrane into a watertight seam, replacing wet adhesive at the laps.

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

A water-based adhesive used to glue an EPDM rubber roof membrane to the deck across its field area. It is rolled onto both surfaces and left to tack off before the membrane is bonded down.

Also: two-part epoxy grout, resin grout, RG grout, Mapei Kerapoxy, Ardex EG15, Kerakoll H40

A two-part grout (resin + hardener) classified RG under BS EN 13888 for tiling in wet or chemically aggressive environments. Used in commercial kitchens, shower enclosures, and anywhere cement grout would stain or deteriorate. Chemical-resistant, stain-proof, and waterproof. Requires accurate mixing and fast, methodical application before the pot life expires. Costs significantly more than cementitious grout per kg.

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: lifetime mortgage, home reversion, later-life lending, home equity release

A borrowing mechanism for homeowners aged 55+ that allows them to access equity in their home without monthly repayments — the debt is repaid on death or entry into long-term care. Two main types: lifetime mortgage (homeowner retains ownership) and home reversion (sells a share of the property). Compound interest can cause the debt to double every 12 years or so at 6%.

Also: lifetime mortgage adviser, equity release specialist, later-life lending adviser

FCA-regulated specialist required for lifetime mortgage and home reversion products. Independent qualified advice is a condition of Equity Release Council Standards 2.0 (May 2025) consumer protections. Relevant to older homeowners (55+) considering equity release to fund an extension.

Also: ERC, equityreleasecouncil.com

The UK trade body that sets consumer protection standards for lifetime mortgage and home reversion products. Standards 2.0 (effective May 2025) include the no negative equity guarantee, fixed or capped rates, the right to remain in the property for life, penalty-free repayments of up to 10% per year, and product portability. Homeowners considering equity release should check that their adviser and product meet ERC Standards.

Also: ERC Standards, ERC Standards 2.0, Equity Release Council Standards 2.0

Consumer protection standards published by the Equity Release Council (Standards 2.0 effective May 2025). Includes the no negative equity guarantee, fixed or capped rates, the right to remain in the property for life, penalty-free repayments of up to 10% per year, and product portability. Products that do not meet ERC Standards lack these consumer protections.

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

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: meter box, gas meter box, electric meter box, gas meter housing, electricity meter housing, recessed meter box, semi-recessed meter box, surface-mounted meter box

The weatherproof enclosure built into or fixed onto an outside wall that houses a relocated gas or electricity meter. Built in during blockwork when a meter is being moved for an extension, with the box type (gas or electric, surface or recessed) and back plate matched to the utility's requirements before the meter operator attends.

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.