Ronseal Diamond Hard Clear Varnish 2.5L Gloss, clear wood varnish, transparent protective finish, hardwearing clearcoat, interior wood sealant

Varnish is a clear or tinted coating that protects wood with a hard film while letting the grain show through, helping it resist wear, water and many household chemicals. This category covers interior, exterior, coloured and floor varnishes, and paint and varnish removers.

Types of varnish

• Solvent-based polyurethane: a tough, high-build finish for furniture, doors and joinery. Many are for interior use only, and brushes are cleaned with white spirit.
• Water-based: acrylic and polyurethane acrylate varnishes dry quickly between coats, and tools wash out in water and detergent.
• Floor varnish: made to stand up to foot traffic on wooden floors, cork and boards. Some are not suitable for laminate, so check the tin.
• Yacht or exterior varnish: a flexible finish for outdoor woodwork such as doors, window frames and cladding, made to cope with rain, sun and frost.
• Coloured varnish: adds a wood shade and protection in one product.

Sheen and application

Choose a gloss, satin or matt sheen. The surface must be clean, dry, sound and free from wax, dust and loose old coatings, and bare wood should be sanded smooth. Stir the tin well before and during use, because satin and matt finishes can dry glossy if they are not mixed. Apply even coats along the grain. Two or three coats are typical, more on absorbent wood or end grain, with a light sand before the final coat. Recoat times run from about two hours for many water-based products to 12 hours for some exterior varnishes.

Safety

Solvent-based varnishes and removers are flammable and give off vapour. Use them in a well-ventilated space, keep them away from flames, and follow the manufacturer's instructions and safety data.

For colour that soaks into the timber, see wood stains and dyes, or browse wood oils.