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Building & Trade Glossary

25 plain-English definitions of common UK building and trade terms. Each entry explains what the term means, why it matters, and links to the relevant TradeCalculator tools.

What Is a Bonding Coat?

What Is a Bonding Coat?

What bonding coat plaster is, when to use it, coverage rates and the difference between bonding and browning.

What Is BS 7671?

What Is BS 7671?

The UK standard for electrical installations explained, covering the 18th Edition wiring regulations and Part P compliance.

What Is a Cavity Wall?

What Is a Cavity Wall?

How UK cavity wall construction works, the purpose of the cavity, insulation options and common problems.

What Is Dot and Dab?

What Is Dot and Dab?

How the dot and dab plasterboard fixing method works, when to use it, and adhesive quantities.

What Is Part L?

What Is Part L?

Part L of the UK Building Regulations explained, covering conservation of fuel and power requirements.

What Is Pointing?

What Is Pointing?

Types of pointing in brickwork, repointing costs, mortar mixes and when to repoint.

What Is an R-Value?

What Is an R-Value?

How thermal resistance (R-value) works, how it relates to U-values and why it matters for UK building regulations.

What Is Screed?

What Is Screed?

Types of floor screed, thickness, drying times and when you need screed for UK floors.

What Is a Skim Coat?

What Is a Skim Coat?

How skim coat plaster is applied, coverage rates, thickness, drying time and when to skim coat walls.

What Is a U-Value?

What Is a U-Value?

How U-values are calculated, Part L targets and why they matter for insulation and energy efficiency.

What Is an RSJ?

What Is an RSJ?

What a rolled steel joist is, when RSJs are needed in UK construction, sizing and installation.

What Is a Soakaway?

What Is a Soakaway?

How soakaways work, BRE 365 sizing, when they are required and installation guidance.

What Is Part P?

What Is Part P?

Part P electrical safety explained: notifiable work, competent person schemes and Building Control.

What Is a DPC?

What Is a DPC?

Damp proof courses explained: types, installation heights, materials and when to replace.

What Is Part B?

What Is Part B?

Part B fire safety explained: fire resistance, escape routes, compartmentation and fire stopping.

What Is Airtightness?

What Is Airtightness?

Building airtightness explained: testing, Part L targets, common leakage paths and sealing methods.

What Is CIS?

What Is CIS?

Construction Industry Scheme explained: registration, deduction rates, verification and monthly returns.

What Is CDM?

What Is CDM?

Construction Design and Management regulations explained: duty holders, F10 notification and compliance.

What Is Tanking?

What Is Tanking?

Basement and cellar tanking explained: Type A, B and C waterproofing systems and when to use each.

What Is a Party Wall?

What Is a Party Wall?

Party Wall Act explained: notice requirements, 3m/6m rules, surveyors and awards.

What Is an EPC?

What Is an EPC?

Energy Performance Certificates explained: ratings A-G, when needed, costs and improvement measures.

What Is MVHR?

What Is MVHR?

Mechanical ventilation with heat recovery explained: how it works, efficiency, installation and Part F.

What Is a Thermal Bridge?

What Is a Thermal Bridge?

Thermal bridging explained: psi-values, common junctions, SAP impact and mitigation strategies.

What Is SAP?

What Is SAP?

Standard Assessment Procedure explained: what it measures, Part L compliance, ratings and calculations.

What Is Permitted Development?

What Is Permitted Development?

Permitted development rights explained: extensions, outbuildings, limits and when planning permission is needed.