DRY LINING PLASTERBOARD TYPES AND USES Dry lining

DRY LINING PLASTERBOARD TYPES AND USES

► Dry lining is also known as : ► Direct Bond or Dot and Dab ► Most common form of plastering used in modern construction. ► Involves securing sheets of plasterboard directly to the background surface, leaving an air space between the plasterboard and the background. ► Using the correct boards, fixing and finishing materials is essential to ensure adhesion and quality of finish.

ADVANTAGES ► Can provide a much warmer house than traditional plaster. ► Plasterboard is a much better insulator than solid plaster. ► The air gap can form an extra insulating layer. ► The speed of construction. ► Has a quicker drying time than solid plastering.

DISADVANTAGES ► Can produce a lot of waste plasterboard if not measured and cut economically. ► Traditional plasterboard has a low impact resistance so can not be suitable for some high traffic areas. ► Plasterboard can disintegrate in wet environments. ► Can be difficult to fix things to eg radiators. ► If the wrong products are used sound insulation can be a problem.

BACKGROUNDS ► Most backgrounds are suitable for Direct Bond eg Brick, Block and Concrete. ► Painted surfaces cannot be dabbed. ► Adhesive will not stick to a wet or damp background. ► All backgrounds need to be free of dust, grease and any large mortar snots.

Backgrounds Concrete might need treating with Thistle Bond It especially if the concrete is very smooth or dense. ► Ceilings should be boarded before dabbing. ► Dabs should not be placed on structural columns, the board and dabs should bridge them. ►

BACKGROUNDS ► Dabs of adhesive should ideally be no less than 10 mm thick and no more than 25 mm thick (when compressed). ► Dabs heavier than 25 mm will sag and give a less secure fixing.

SERVICES ► Any electrics or pipe work should pass behind the board in the airspace. ► Pipes or wires thicker than the airspace should be chased into the background.

SETTING OUT ► The first thing to do is identify the high spot of the wall. ► This could be a bump, a prominent brick or anything that stands out from the wall. ► Transfer the high spot by plumbing it up to the ceiling and down to the floor.

SETTING OUT The first mark shows the high point. ► Add at least 10 mm for the thickness of the dab. ► Add on the plasterboard thickness eg. 12. 5 mm, 15 mm. ► Transfer the mark using a chalk line along the ceiling and wall. ► This gives you a line for the front edge of the plasterboard. ►

Direct bond ► Building regs. require a continuous fillet of adhesive around the perimeter of the wall to prevent the movement of air. ► A solid line also aids in the fixing of skirting boards etc, . ► Any services , pipes, sockets, mounting points should be well supported with dabs of adhesive.

Dabs of adhesive should be positioned in three vertical rows across the width of the board. ► Any boarding should be started in internal angles. ► Dabs should be placed near any board joints. ► Dabs should be no more than 300 mm apart. ►

Placing plasterboard Plasterboard packers should be placed under the board before fixing. ► This helps prevent the travel of moisture up the board from the floor. ► Helps to level boards up if the floor is uneven. ► Lifts the board tight up to the ceiling. ►

► Place board gently against adhesive compound dabs. ► White side of board facing out. ► Rest board on plasterboard packers.

► Tap the board gently but firmly with a straight edge. ► Board should align against the chalk lines along floor and ceiling. ► Tolerance expected along a 2 m straight edge is +/- 3 mm.

Angles ► External angles should be well supported with dabs. ► Dabs provide strength and a fixing point for angle beads. ► Board edges should finish flush with each other to provide a neat angle.

Plasterboards ► Plasterboards are available for a variety of applications and specifications. ► Thicknesses available are 9. 5 mm, 12. 5 mm, 15 mm and 19 mm. ► Sizes are 1200 mm x 900 mm, 1800 mm x 900 mm, 2400 mm x 1200 mm and 3600 mm x 1200 mm. ► Plasterboard can be used for fire control, sound insulation and thermal insulation.

Fire resistant ► Produced with glass fibre and other additives in the core. ► Used in partition, wall lining and ceiling systems for increased fire protection. ► Used to protect structural steel. ► Pink face paper.

Moisture resistant ► Has water repellant additives in the core and paper liner. ► Can be used as a base for tiling in wet areas. ► Green paper on face and reverse.

Sound ► Has a higher density core. ► Used where greater levels of sound insulation are required. ► Pale blue face paper.

Thermal boards. Wallboard which is factory bonded to an expanded polystyrene insulant. ► Optional with vapour check to reduce risk of condensation. ► Used in refurb or new build where a basic level of additional thermal insulation is required. ►

Impact resistant Duraline has a higher density core with glass fibre and other additives. Ø Used to give a greater impact resistance in heavy use areas. Ø Ivory face paper. Ø

Fixing plasterboard

Centres and Spacings ► 9. 5 mm plasterboard should be fixed to centres no more than 400 mm apart. ► 12. 5 mm and 15 mm boards should be fixed to centres no more than 600 mm apart. ► Nails used for fixing should be galvanised and approx. 3. 5 x the depth of the board. ► Screws should be zinc plated and no less than 2. 5 x the depth of the board. ► Nails are spaced at 150 mm apart. ► Screws are spaced at 230 mm apart.

► Plasterboards should be staggered when fixed to ceilings and studs. ► This helps to prevent long, ‘line through’ cracks. ► Methods of joint reinforcement are Hessian, Fibre Tape and Paper Tape. ► Plasterboard joints should have a gap of no more than 3 mm apart. ► Always try to keep ‘factory’ edges together. ► Any cuts should be placed in internal angles or behind beads.

Skimming to plasterboard Joints between plasterboard joints and all internal angles between wall and ceiling need reinforcing. Use Cotton scrim, Hessian ( jute) or fibre tape. If using hessian allow all joints to set before applying finish.

TAPE AND JOINTING Used in many dry lining specifications. ► Lots of products are ready mixed. ► Joint Cement, Joint filler and Easi fill. ► Joints are reinforced with paper tape, angles use beads or metal reinforced corner tape. ►

TAPE AND JOINTING ► Tape is bedded on with material. ► Joints filled out into tapered joint. ► All screws are filled. ► All joints will need sanding down. ► Wall is then sealed with dry wall sealer.

Beads for plasterboards. ► Skim Bead. ► Used on external angles for finishing coat. These beads cannot be plumbed or levelled up, they are governed by their background. ► Nailed or screwed on.

SKIM STOP BEAD ► Used to provide a neat finish to an opening or to form a panel. ► 3 mm depth. ► Nailed or screwed on.

MOVEMENT BEADS ► Used if there is an expansion joint in the background. ► The V in the bead will slot into the slot left in the plaster boarding. ► Flexible V insert allows bead to move without cracking finish. ► Nailed or screwed on.

PLASTERBOARD EDGING BEADS ► Slots over the edge of plasterboard. ► Provides neat, clean finish. ► Protects edge of plasterboard. ► Different widths to suit thickness of plasterboard.

RE CAP ► Using the correct boards, fixing and finishing materials is ………………… to ensure adhesion and quality of finish. ► An advantage of dry lining is its ………………. of construction. ► A disadvantage of dry lining is plasterboard can…………. in a wet environment. ► Dabs ……………. . be placed on structural steel columns.

RE CAP ► Dabs of adhesive should ideally be no less than ……………. thick when compressed. ► The first thing to do when dabbing is to……………… the high spot. ► Any boarding / dabbing should be started in………………… angles. ► A moisture resistant plasterboard has a ………………… coloured face paper.

RE CAP ► 12. 5 mm plasterboards should be fixed to centres no more than………… apart. ► Gaps between plasterboard joints should be no more than………………… apart. ► Plasterboard thicknesses are 9. 5 mm, 12. 5 mm, ………………… and 19 mm. ► When fixing with screws the spacings should be no more than……………. mm apart.