Summary
The following topics contain general information about 
common types of paints and primers

	1	What is paint?
	2	Interior emulsion
	3	Exterior emulsion
	4	Interior gloss
	5	Exterior gloss
	6	Primers
	7	Undercoat
	8	Anti-condensation paint
	9	Enamel paint

Step 1 - What is paint?
Put simply any paint is a mixture of pigments (colours) 
and binders suspended in liquid. The liquid can be just 
water or a mixture of resins. As the paint dries the 
liquid will evaporate leaving the pigments and binder on 
the surface.

Step 2 - Interior emulsion
Emulsion is a relatively economical water based paint 
designed to cover large areas and surfaces such as newly 
plastered walls and lining wallpaper. Often there is a 
choice between matt and silk finishes.

Step 3 - Exterior emulsions
Emulsion that is used outside has additives that help the 
paint cope with variations in temperature and humidity. 
Exterior emulsions have a matt  finish but vary in 
smoothness. Smooth paints can be used on smooth and 
textured walls. Textured paints are to give walls a 
textured surface, for example to cover a non-structural 
defect.	

Step 4 - Interior gloss
Gloss is solvent or oil-based paint designed to give extra
protection to wood and other surfaces. Primers are used to
seal new wood. Undercoats provide a pigmented base (close 
to the topcoat’s colour) for the topcoat. Combined acrylic
based primers and undercoats are available. Non-drip paint
is a gel that breaks down to a liquid as you brush. 

Step 5 - Exterior gloss
Exterior gloss is formulated to with stand the weather and
provide a surface capable of expanding and contracting 
without cracking. The gloss forms a permeable skin through
which wood can ‘breath’ and through which moisture can 
escape. Exterior gloss must be used in conjunction with 
exterior primer that forms a similar permeable layer.

Step 6 - Primers 
Primer seals pores in absorbent surfaces. Bare wood needs 
priming before painting. New windows and doors come ready 
primed but check for scratches that may need re-priming. 
Knots in wood may leak natural resin so a special primer 
is available for them. Other surfaces that require 
sealing and those that require a key such as exposed 
metal will also need priming. 

Step 7 - Undercoat
Undercoat is specially formulated paint that has more 
pigment than topcoat. Not using an undercoat on a dark 
surface can prove a false economy where the old colour 
is darker than the new one because you will need to use 
several layers of expensive topcoat to stop the old colour
showing through. The undercoat provides the correct base 
colour to match the topcoat colour. 

Step 8 - Anti-condensation paint
Anti-condensation paint is a semi-porous emulsion that 
does the neat trick of absorbing water in the air and 
allowing it to evaporate later without ruining the 
paint itself. Some brands contain a fungicide to prevent 
mildew growing. It’s mainly for use in kitchens and 
bathrooms. This paint will not cure chronic damp.

Step 9 - Enamel paint
Enamel is normally used for painting metal and wood. It 
is very hard-wearing and the pigment particles are very 
finely ground.