Painters and decorators A–Z dictionary
UK trade reference · plain English
A paint finish is a system of preparation, compatible products and suitable drying conditions. Colour is only the visible final choice. Primer, undercoat, mist coat and stain blocker do different jobs; a single improvised sealer does not replace them all. Persistent staining, peeling or mould should trigger investigation of moisture or compatibility. Control preparation dust and check the product guidance for the actual background.
This A–Z combines useful technical vocabulary with links to full references where the article meets our depth and sourcing checks. An unlinked definition is intentionally kept here rather than turned into a shallow standalone page. Read a quotation against its actual scope: a familiar word is not a complete specification.
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A
- Adhesion
- The bond between a coating and its background. Contamination, incompatible layers and poor preparation can undermine it.
B
- Bleeding
- Discolouration passing through a coating from the material beneath. Identify its cause before choosing an isolating treatment.
C
- Caulking
- Caulking fills or seals specified joints using a suitable product, often as part of decorating. A paintable decorator's caulk differs from a wet-area silicone sealant or a tested fire-stopping product. The joint, movement, exposure and finish determine what is appropriate; the word caulk does not identify one universal material.
- Cutting in
- Painting a controlled boundary around edges and details, coordinated with the main coated area to avoid visible differences.
D
- De-nibbing
- Removing small raised particles between suitable finishing stages. The method must suit the coating and control dust.
- Denib
- Remove small raised particles or nibs from a finish, usually by suitable light abrasion between stages.
F
- Flash
- Show an uneven patch of sheen or appearance after drying. Investigate absorption, preparation and application rather than just adding water.
- Flashing
- An uneven appearance or sheen after drying. Background absorption, local repairs and application conditions may contribute.
G
- Getting into painting and decorating
- Painting and decorating is the assessment, preparation and finishing of surfaces using compatible coatings or wallcoverings. The trade needs product knowledge, protection and an agreed finish, not just quick brushwork. A trainee should understand when an existing surface needs investigation rather than stronger sanding or another coat.
K
- Key
- A surface condition or preparation intended to help adhesion. The right method depends on the coating and background.
- Knotting solution
- A product used in compatible paint systems to limit staining from resinous timber knots. Follow the coating system’s instructions; it does not repair rotten or persistently wet timber.
M
- Masonry paint
- Masonry paint is a coating selected for a suitable masonry or render background. Products vary in appearance, water resistance, vapour behaviour and application conditions. It is not a universal waterproof barrier, structural repair or cure for every damp wall, and a product intended for one surface may not suit another.
- Mist coat
- A mist coat is a suitably thinned first paint coat used on dry, porous new plaster where the paint manufacturer specifies that approach. It helps prepare the surface for later coats. It is not a standard ratio of any leftover paint and water, and it is not a remedy for damp or unsound plaster.
O
- Opacity
- A coating's ability to obscure the surface beneath. Colour choice and preparation can affect the system needed.
P
- Primer
- A primer is a preparatory coating selected to help a compatible finishing system perform on a particular surface. It may address adhesion, suction or other defined requirements. Primer, undercoat, stain blocker and stabiliser are not universally interchangeable, and one multipurpose label does not prove suitability for every background.
S
- Stain blocker
- A coating intended to isolate particular staining. It does not repair the leak or moisture source causing a recurring mark.
U
- Undercoat
- A specified intermediate coating supporting the finishing system. It is not interchangeable with every primer or topcoat.
W
- Wood filler
- Wood filler repairs suitable local defects as part of a specified timber-finishing process. Products differ in composition, movement, exposure and coating compatibility. A decorative filler is not automatically a structural repair, a treatment for decay or a substitute for investigating why a joint or damaged area has failed.
Read the slang and site language dictionary · Browse related encyclopedia references
Sources and further reading
Linked article sources support the technical background; informal usage is editorial and varies by region. Full specification and legal requirements must be checked in the original.
- Dulux: painting new plaster
- HSE: control preparation dust
- National Careers Service: occupational routes and duties
- HSE: hazardous-substance assessment
- GOV.UK: fire, sound and moisture context
- Dulux Trade: compatible coating preparation
- Dulux Trade: product-specific masonry guidance
- GOV.UK: moisture guidance
Sources checked: 8 November 2026. General reference, not instructions for safety-critical DIY. National regulations and current standards must be checked for the project.
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