Solid Wall

Solid walls will be very hard, if you knock on the wall whilst moving your hand around it is unlikely that you will see any flex or hear any hollow areas or voids.

Typical characteristics

• Very hard, solid feeling wall with no flexing
• Dull sound when knocking, rarely with hollow sounding areas 

Dot and Dab Wall

The easiest method of identifying this type of wall is to tap on the wall whilst moving your hand around. You will hear that most of the wall sounds hollow and may even have a slight flex to it, however there will be hard, solid points dotted around. These are the areas that have adhesive “dabs” bonding the plasterboard to the solid wall behind, these would typically be placed in a grid pattern around 300-500mm apart.

Typical characteristics

• A solid feeling wall with slight flex in certain areas
• Generally hollow sound when knocking with solid/dull areas dotted around

Plasterboard Wall

Plasterboard walls are typically made from some sort of board material that is supported by a framework. They are almost always internal, non load bearing walls. Plaster board walls can have a timber or pressed steel framework. This will usually run vertically at regular intervals between 300 and 600mm with short horizontals between each. Plasterboard walls will almost always sound hollow when knocking on them and have some flex or movement in them.

Typical characteristics

• A slight flex or movement to the wall when pushing on it
• A hollow sound when knocking with slightly more solid areas in vertical lines

Whatever type of wall you have, beware of pipes and cables hiding under the surface – don’t drill through them!