Plasterboard and Insulating Boards

Types and treatment

The huge range of boards made for lining walls and ceilings are known as building boards. The term also covers the various types of hardboard and chipboard and many others not used in furniture making. These fall into three principal groups.

Insulating boards

These lightweight, porous boards, made from fibre, provide thermal and sound insulation. Their colours vary from cream to brown and grey, though some types are factory-finished with white paint.

Some insulating boards are impregnated with bitumen for greater water resistance and flame-retardant grades are also made.

Sizes: the usual width is 1220 mm (4 ft), in lengths from 1830 to 3660 mm (6 to 12 ft), but 610 mm (2 ft) widths are also available. Thicknesses are 12, 18 and 25 mm.

Cutting: use a sharp trimming knife for a clean cut, or a fine-tooth tenon saw.

Fixing: nail insulating boards to studs with 40 mm (1-1/2 in) galvanised clout nails spaced 100 mm (4 in) apart at edges and 200 mm (8 in) elsewhere. The stud centres should be no more than 400 mm (16 in) apart for 12 mm boards, 600 mm (24 in) for thicker boards. Nail small areas so that they are fully enclosed.

Joints: cover joints with wooden fillets.


Plasterboard consists of a core of plaster of Paris sandwiched between two sheets of heavy paper. Some plasterboards have aluminium foil backing to provide increased heat insulation.

Plasterboard can be used with the grey side outwards for skim-coating with board-finish plaster, or the ivory side for painting or papering. Before papering or painting plasterboard, seal it with a primer recommended by the manufacturer.

Sizes: eight lengths from 1830 to 3660 mm (6 to 12 ft) are made in widths of 610, 915 and 1220 mm (2, 3 and 4 ft). Thicknesses are 29 and 12 mm

Cutting: use a fine-toothed saw or a trimming knife. Score the paper on one side with the knife, crack the board along the scored line and then cut the paper on the other side. Cut edges can be trimmed with a Surform.

Fixing: nail to studs with 40 mm (1-1/4 in) galvanised clout nails at 150 mm (6 in) intervals. Cover the nail heads with filler.

Joints: leave 3 mm (1/8 in) gap between boards and fill the gap with special joint filler. Joints can also be covered with paper, cotton or linen sealing tape. Some tapes are self-adhesive.

27. June 2011 by admin
Categories: Timber, Woodworking | Tags: , | Comments Off on Plasterboard and Insulating Boards


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