How to avoid problems with glancing light

General
• Glancing light causes defects to magnify in any surface.
• Under certain lighting conditions, it is almost impossible to hide joins in plasterboard.
• Often glancing light problems are reduced once curtains have been installed .
• Take more care with areas prone to glancing light.
• Here are some areas that are prone to glancing light.
• Long walls such as hallways.
• Large flat ceilings with large windows at the end of the room.
• Ceilings near high windows.
• Walls near sky lights
• Stair wells
• Glare from floor tiles or even the next door neighbors roof!
• Down lights shining onto a wall
• Light stands reflecting into a corner
• The normal standard for plastering is known as level 4 finish.
• Level 4 finish is not good enough in glancing light areas if you want a near perfect finish.
• The solution is a level 5 finish (explained below)
• Plasterer would rarely include for a level 5 finish in their quote unless requested.

Suggestions to reduce the effect of glancing light
• Block or diffuse light source
• Use flat paint.
• Paint with a fluffy roller.
• Avoid dark colors.
• Apply a texture finish
• Use a level 5 plastering finish in effected areas.
• Create an opposing light source.

For more information on glacing light.

Level 5 finish

Even a completely flat join can show with the effect of glancing light. The reason for this is that the join has a different surface texture to the board. A level 5 finish creates a single wall texture, that will hide this effect.
To create a level 5 finish the joins should be finished off as normal, then a skim coat of top coat is applied to the entire surface. Then lightly sand back to a smooth even finish.

For more information on level 5 finish.