Dry-lining - ‘Dot and dab’

The use of adhesive dab is the simpler and more popular of the two systems. It comprises a series of adhesive dabs applied by trowel to the wall. These are typically 50mm to 75mm wide and 250mm long. Three columns of dabs are normally required per board (9.5mm board 1,200mm wide usually requires four) with horizontal dabs between the columns at ceiling level, and a continuous band of adhesive at skirting level. When the dabs are in position, the board (cut 15mm short of wall to ceiling height) can be pressed and tapped into position, tight against the ceiling. It is temporarily supported at floor level by off-cuts of board. An insulated closer or an accredited closing detail, possibly using an insulated reveal board, should be used to prevent cold bridging, air leakage, condensation and mould growth around openings. Reflecting concerns about heat energy losses due to casual draughts and air leakage, the Building Regulations are demanding and testing for higher levels of effective airtightness. There have been some reported problems with the airtightness of dot and dab applied dry-lining, so the effective and complete application of the requisite adhesive in continous bands, particularly around openings and service penetrations (such as socket boxes), is essential.