Varnish

Varnish forms a thin, hard film on the wood. It comes clear or tinted in wood tones, in matt, satin or gloss. Outdoors, on pergolasPergolaAn open shade structure in a garden, on a terrace or a roof, made of posts and beams with slats, reeds, fabric or plants on top. It is often made of wood., doors, shutters and decking, exterior varnishes with UV filters are used; interior varnishes do not stand up to the sun.

On new or bare wood, a wood preservativeWood preservativeA liquid that soaks into wood and protects it from fungi, rot, woodworm and moisture. It goes on bare wood, usually before varnish or paint. usually goes on before the varnish to protect against fungi, rotWood rotDecay of wood caused by fungi when it stays damp for a long time. Rotten wood goes soft, gives when pressed or crumbles, and can't be saved with paint. and insects. The surface is sandedSandingSmoothing a surface with sandpaper or a power sander to remove bumps, loose old paint or gloss, so the new paint or varnish grips well and comes out smooth. and cleaned of dust, and it gets a light sanding between coats so the next one bonds.

In the sun, varnish dulls, cracksCrackA split or gap in render, concrete, a wall, a coating or wood. Fine cracks are usually only on the surface; ones that grow, keep reopening or run diagonally need attention. and peelsPeeling paintWhen paint loses its grip and lifts off in flakes or sheets. It is almost always a sign of a problem underneath, usually damp or poor preparation. over time, and the wood underneath turns grey. Regular maintenance, with a light sanding and a fresh coat before the varnish reaches that point, is far easier than stripping all the wood back and starting again.