Undercoat & Primers

Learn more about undercoat & primers

Primers and undercoats establish a solid bond on non-porous, or high-suction surfaces before topcoating. Modern multi-surface primers bind directly to glass, tiles, uPVC, and power-coated metals without requiring extensive abrading. Pairing your final finish with a colour-matched undercoat maximises opacity, reduces the total number of topcoats required. 

Typical uses

• Bare timber and joinery: Sealing raw softwood, hardwood, and MDF edges to prevent uneven suction and resin bleed-through.

• Ferrous and non-ferrous metals: Protecting various metal surfaces from rust and oxidation before painting.

• Stain and damage sealing: Blocking water stains, soot and nicotine from ruining fresh emulsion or gloss topcoats.

• Difficult surfaces and tiles: Priming smooth melamine, glass, wall tiles, and uPVC trims to allow topcoat paint adhesion without flaking.

How to choose the right undercoat & primers

• Start with the surface, then choose by material. Check whether the surface is bare or already painted.

• Confirm whether the job is interior or exterior.

• Weigh up the paint type. Water-based wood primer suits interior work and tighter schedules, while oil-based wood primer is often chosen where a longer drying time is acceptable.

• Check the surface condition. MDF edges, knots and resin pockets may need a sealing primer, stain-blocking undercoat or wood primer sealer.

• If the surface is old gloss or varnish, key it properly or use a bonding primer where needed so the new coat can grip.

Before you order

• Measure the area in m², then check the coverage rate on the product specifications.

• Add for wastage and allow for a second coat where the substrate is bare or porous.

• Check the drying time and recoat time on the tin so the project stays on track.

• Confirm whether the product is intended for interior or exterior use.

• Make sure the application suitability matches the surface you are painting over, whether that is metal, bare wood, old paint or varnish.

• Clean the surface, sand where needed to key it, and remove dust before you start.

Explore our range of undercoat & primers

Compare wood undercoat paint by surface material, finish type and tin size, then choose the option that suits the job in hand. If you need a primer and undercoat look for a primer undercoat to do both jobs in one to save time. If you are covering a previously painted surface, a separate undercoat may be the better fit.