Timber Surface Treatments and Finishes

Why finish timber?

Bare timber soaks up moisture, picks up dirt, wears down and can even rot. A surface finish protects the wood, improves how it looks, or does both. This module covers the main timber finishes and, for the marks, why you would choose each one.

The language of finishing

Four ideas run through the topic:

Spot the protective reason

Which of these is mainly a PROTECTIVE reason for finishing timber?

• Sealing the wood so it resists moisture and does not rot
• Adding a bright colour to match a room
• Showing off the natural grain pattern
• Giving the wood a glossy, decorative shine

Match each finish to what it does

Protect, decorate, or both?

Most finishes lean one way, though several do both. Knowing the lean helps you pick one and state a reason.

Which are mainly decorative?

Select the TWO finishes used MAINLY for decoration.

• Wood stain, which adds colour while showing the grain
• Shellac, a high-gloss traditional French polish
• Exterior varnish on a garden gate
• Oil rubbed into a wooden chopping board

Complete the finishes

A finish is applied to timber for _____, decoration, or both. _____ gives an opaque coloured coat that hides the grain, while a _____ adds colour but lets the grain show. A clear, hard _____ mainly protects and still shows the grain. A thin layer of attractive wood glued to a cheaper base is called a _____.

Name it, then justify it

For full marks, do not just name a finish, say why: is it for protection, decoration, or both? For example, an outdoor bench needs varnish or oil for water protection, while a jewellery box suits shellac or wax for decoration. Veneering is different: instead of a coating, a thin sheet of attractive or expensive wood is bonded to a cheaper board, giving a costly look at a lower price.

Apply a finish

Put the steps for applying a surface finish to timber into a sensible order.

• Sand the surface smooth
• Wipe away all the dust
• Brush or wipe on a thin first coat
• Let the coat dry fully
• Lightly sand, then add further coats

Choose the right finish

Pick the best finish for each product, thinking about protection and decoration.

• A garden bench that must survive rain and sun. Which finish suits it best?
• A decorative jewellery box for indoor display. Which finish suits it best?
• A cheaper board that needs to look like expensive walnut. What is the best treatment?

Protect, but show the grain

A designer wants a finish that PROTECTS an oak table from spills but still lets the beautiful grain show. Which is the best choice?

• Varnish, a clear protective coat that lets the grain show
• Paint, an opaque coat that hides the grain
• A wood stain on its own, which mainly adds colour
• Leaving the table completely unfinished

What each finish actually does

Tap the TWO statements that are correct about timber finishes.

• Paint gives an opaque coat that both protects and decorates.
• Varnish hides the grain of the wood completely.
• Veneer is a thin layer of attractive wood bonded to a cheaper base.
• Wax gives a permanent finish that never needs redoing.
• Oil sits on top of the wood as a thick, glossy shell.

Recommend a finish

A student is making a wooden chopping board for a kitchen. Recommend a suitable surface finish and justify your choice, then explain why a high-gloss shellac would be a poor choice here.

• Name a suitable finish and say whether it is for protection, decoration, or both
• Explain why it suits a surface that meets food and water
• Explain why a designer should always state the reason for a finish
• Explain why a high-gloss shellac would be a poor choice for a chopping board