Wood Stains, Preservatives, and Varnishes

Wood Stains, Preservatives, and Varnishes brush and paint can

There is a confusing number of products (both oil- and water-based) designed to enhance and protect the wood. Still, broadly speaking, they can be split into three categories: those for exterior use, those for interior use, and those that can be used both on exteriors and interiors.

Wood Stain

Wood stain can be either semi-transparent (which allows the natural grain of the wood to show through) or opaque (which offers a coloured alternative and is often used where the natural colour of the wood is to be changed). Wood stains can also be subdivided into high-build and low-build finishes.

High-build wood stains are thicker (more viscous) than low-build wood stains and protect the wood by creating a thick film coating. They work by partially penetrating the wood and by clinging to the wooden surface.

Low-build wood stains are thinner, and, to be effective, rely on penetrating the wood and forming a thin coating on the surface.


Sometimes referred to as preservative basecoatsOpens in a new tab., these products are intended to penetrate deeply into untreated wood and protect it against rot and ultraviolet rays. These preservatives are sometimes treatment in themselves or are often applied before the wood stain. Still, in many cases (just to confuse things further), there are products described as preservative wood stains that both preserve and give a stained finish.

Coatings That Simulate Wood Stain

These products are used where a wood effect is required on top of a previously painted surface or an uneven wood finish needs obliterating. They consist of a colouredOpens in a new tab. base coat, which, when dry, has a semi-transparent top coat that is applied sparingly and then brushed out rather coarsely to simulate wood grain (rather like the old-fashioned graining scumble). The product needs at least 16 hours to dry between coats, and sanding should be avoided. The top coat dries to a sheen finish.

What to Choose?

So from all this confusion, how do you decide which product to use? To come to some decision, the following factors need to be considered:

•Is the product to be used on exterior or interior woodwork?

•What degree of wear and tear will the finished surface be exposed to?

•Is the product just to enhance and decorate, or does it need to preserve and protect the wood, or does it need to do both?

•Do you want to hide or change the colour of the existing wood surface?

•Do you want a matte finish or one with a sheen?

•Does a strong odour matter? For instance, are you using it in a kitchen or a bedroom where it may matter? If so, choose a water-based stain that has less odor than an oil-based product.

If in doubt, consult the various product information leaflets, often available in the store where you buy the products. You may also read the information usually displayed on the side of the product’s container.

Wood Dyes

These are thin spirit-based liquid colors usually come in wood colors such as teak, mahogany, oak, etc. These penetrate bare wood surfaces to change the original color. The dye-coated wood usually needs overcoating with a finish such as a varnish.

Varnishes (Oil- or Water-Based)

There are two categories of varnish: interior and exterior quality, which come in either gloss, eggshell, satin sheen, or matte.

Natural Wood Finishes

Products such as teak oil (for teak wood) and boiled linseed oil (for oak) enhance the natural color of woods Opens in a new tab.but tend to be slow-drying and not as protective as high-build varnish.

Measuring for Paint

Before estimating the quantity of paint, you will need, remember that how far a can of paint will go is affected by the following factors:

•Porosity (amount of suction) of the surface

•Whether the surface is smooth or rough or textured

•Type of paint

•Viscosity (thickness) of the coating.

Measuring Ceilings

The easiest way to measure a ceiling is to measure the floor beneath it (if possible). Measure the length times the width to get the square area.

Measuring Walls

To measure a single wall or part of a room, measure the height of the wall and multiply by the length of the wall to get the square area.

To measure all the walls of a room, measure the walls’ heights and multiply by the room’s perimeter (length around the room) to get the square area.

Measuring Woodwork

Smaller areas such as doors and windows can be measured individually; then the areas added together to give a total square area.

Measuring Woodwork


When you have measured up and obtained the square area, you can use the manufacturer’s suggested coverage figures on the paint can (or paint leaflet) to work out how much paint is needed. For example:

You measure the perimeter of a room and the height and multiply the two to arrive at the square area, say 76 square yards (approximately 64 m2). The manufacturer’s suggested spreading rate is 19 square yards (16 m2). Then if you divide the 76 square yards by the 19 square yards, you will find that you need 4 quarts of paint.

Note: Remember, paint goes further when second-coating (having reduced the suction), so you can calculate less paint for the second coat.

Typical Areas Covered by Paint per Quart

Vinyl silk: 17–19 square yards (14–16 m2) Vinyl matte emulsion:

16–20 square yards (13–17 m2) Undercoat: 19 square yards (16 m2) Gloss: 20 square yards (17 m2)

Typical Areas Covered by Paint per Quart

Tools for Painting

Equipment for painting comes in a baffling array—brushes, rollers, protective materials, and trays are among the necessary items you may need to acquire before you start to work on your project.

Roller extension handle

Paint pads

Mineral spirits

Paint shield

Masking tape

Small foam rubber roller and tray



7 in. (178 mm) flat brush

2¾ in. (68 mm) or

3 in. (76 mm) paintbrush

1½ in. (38 mm) paintbrush

½ in. (13 mm) paintbrush


Getting Ready to Paint

Before you begin to paint, you must protect the furniture and fittings in the room in which you plan to decorate. While moving furniture out of a room might be preferable, sometimes this is not possible.

1.Move large furniture items away from the walls to the center of the room.

2.Leave gaps between some furniture items; this will allow you to move from one side of the room to the other when painting ceilings using a roller on an extension pole handle.

3.Move smaller pieces of furniture around the larger ones and remove ornaments and pictures to another room. Chairs can be stacked upside down on top of each other or on top of settees or sofas.

4.Cover up furniture with drop cloths or plastic sheets.

5.Cover up the floor area with drop cloths; old bed sheets will do, but it’s best to use double them, as they are not as thick as drop cloths. Newspapers are handy for smaller areas.

6.Protect light fittings, including wall lights, by draping or wrapping sheets of newspaper around them and fastening them in position with masking tape. You may also slip plastic bags over the fittings.

Safety note: The light bulbs must be removed to avoid any fire risk.

Preparing Paint for Use

Before opening a can of paint, dust off the lid and the can’s grooves. Always place a hand over the top of the paint can lid when levering it off; this will prevent the lid flying up and scattering paint upward.

The best and safest way to lever off a paint can lid is to place the screwdriver or flat-bladed knife sideways into the edge of the lid groove, and not at right angles to the lid where it can slip.

Removing Paint Skins

1.If the top of the paint has formed a skin, cut around the edge of the skin where it meets the edge of the can with the point of a putty knife, chisel knife, or a wide screwdriver.

2.Next grip hold of the skin’s middle and lift it out (disposable gloves are useful for this).

3.Place this in an old empty can or on a double sheet of newspaper. The skin can be folded up inside and disposed of.


Sometimes a paint skin will not form very thickly and is too flimsy to get hold of easily. So after cutting around the edge of the skin, place a small square of newspaper onto the center of the skin. Grip hold of this and remove the skin, which will be stuck to the paper.

Stirring Paint

Using a clean, flat, narrow stir stick, stir in a circular motion, first clockwise, then counter-clockwise.

Lift the stick up and down as you continue the circular stirring; this helps to mix the pigment into the paint media.


When using more than one can of a particular color, it is good to pour the cans into a large container (such as a bucket) and stir them together. This will avoid any slight colour changes between one and another. If the bucket has a lid, the paint can be stored in this.

Straining Paint

Sometimes paint becomes contaminated with bits, either pieces of broken paint skin or dirt introduced from the surfaces being painted. It is, therefore, necessary to remove these by straining the paint. This can be done by passing the paint through an old kitchen sifter or through a piece of pantyhose, which can be attached to a paint bucket with either an elastic band or string.

The Advantages of Using a Paint Bucket

Using a paint bucket has several advantages:

•A paint bucket holds a smaller quantity than the stock can and is, therefore, lighter and more convenient to hold and carry.

•The paint left in the stock can remains untouched and, therefore, stay clean.

•If the lid is replaced onto the stock can, the paint is not exposed to the air and, so consequently, does not thicken up.

•A paint bucket is not as deep as the stock can, so it is easier to dip brushes into it.


Attach string or wire across the paint bucket from the two handle fixings. This makes it possible to scrape off excess paint and lay the brush conveniently across the wire.


A good method of keeping a paint bucket clean is to use a plastic container inside the bucket (for the paint). A good makeshift plastic container can be made easily by cutting an empty soda bottle in half. A 3-litre (6-pint) bottle is a good size, although a 2-litre (4-pint) bottle will do. An added advantage is the area between the plastic container and the paint bucket, where it is possible to stand paintbrushes during use.

How to Use a Paintbrush (Undercoating and Glossing)

Safety note: Always keep the room well ventilated.

When Using a New Paintbrush for the First Time

1.Before dipping into the paint, bend the bristles backwards and forward to remove any loose hairs.

2.Dip the bristles into the paint, no more than two-thirds of the way up the bristle.

3.Dip the loaded brush against the inside of the paint bucket to get rid of surplus.


•Before applying gloss paint, warm the room. Gloss flows better and “checks” (reaches its initial drying stage) more easily.

•To help prevent paint runs or sags, point a fan heater at the door (not too close, though) following glossing. First make sure that the floor is clean.

•To check that paint is dry, always use the back of your fingers, not the tips, which can leave marks.

How Do I Know How Much Gloss to Apply?

1.As you brush the gloss onto the surface, it should flow easily without too much “pull” on the bristles.

2.When you “lay off” the gloss, there should be a certain amount of pull on the bristles.

Do not overbrush, as this can cause the paint film to roll back on itself and not cover very well.

Do not underbrush since this can cause paint build-up and “sags,” “runs,” and “curtains”

Applying the Paint

1.Apply the paint in random overlapping strokes.

2.Lay out the paint with horizontal cross strokes.

3.Lay off vertically, finishing on upstrokes.

4.If applying undercoat, use the tips of the bristles during the final lay off.

5.If using gloss paint, use the sides of the bristles during the final lay off.

6.Lift the brush off the surface as you come to the end of the laying-off stroke.

Painting Woodwork

Try to keep a “wet edge” when painting (that is, try to keep moving the outer edge of where you are painting). This avoids overlapping brush marks and runs. To do this it is best to work to an application sequence (see below):

Painting Flush Doors

1.Remove door furniture, handles, finger plates, etc.

2.Paint the door edges first.

3.Work in small rectangles (see numbered diagram, below).

4.Blend each painted block into the next with both horizontal and vertical brush strokes.

Note: Brush the paint outward toward the edges (see above). This avoids paint build-up and possible runs at the edges.

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