Definition - What does Dead Flat mean?
Dead flat is a coating or paint with absolutely no gloss or sheen. Ceiling paints are dead flat paints. A dead flat paint hides lapping marks and roller directional pattern (as well as other application imperfections) better than a standard flat paint.
Dead flat is water-based interior paint which can be used on wood, plaster and metal.
Flat sheens are prone to absorb dirt and grime, making them stain easily and somewhat difficult to clean.
Corrosionpedia explains Dead Flat
Dead flat is a water-based paint made using a traditional alkyd resin. It provides a completely flat finish with quick application and minimal stippling.
A dead flat paint means it has virtually no light reflectivity, which tends to hide flaws and imperfections well. The main problem with a flat sheen is that it is more difficult to clean, so it is suggested that this type of paint be used in areas which do not often require cleaning.
One benefit of this paint is not only its ability to hide flaws, but it also tends to cover better than glossier paints. A flat sheen also tends to have a slightly rough feel in comparison to other sheens. It is suggested for use in bedrooms, dining rooms, living rooms and ceilings. It is not suitable for kitchens, bathrooms or external surfaces.