4. Cover all fastener heads and fill any surface damage with compound. Allow to dry for at least 24 hours.Second coat1. Scrape or sand off any lumps and apply a second coat extending 200mm either side of the joint using the 200mm broadknife.2. Smooth down the joint edges with a trowel to reduce the need for sanding later. Allow to dry for at least 24 hours. Finish coat1. Scrape or sand off any remnants and apply a thin finish coat of compound around 250–300mm each side of the joint using your largest broadknife or trowel.2. Feather the joint edges with a trowel.3. Apply a coat to all fastener heads in a different direction to the previous coat and extend around 25mm further beyond it. 4. Allow to dry for at least 24 hours before sanding.Cover fastener heads250mmapprox.2mm typical build up over tape1.0mm minimum depth of compound under tapeGYPROCK plasterboard (square edge butt joint)Paper tapeFinish with slight convex camber over jointCover fastener heads170mmapprox.
EXTERNAL CORNERSFor external corners, use the same three coat jointing system on top of the external corner bead, as for the rest of the wall.1. Using a 150mm broad knife, apply a coat of Gyprock Multi-purpose Joint compound over the fixed metal angle, about 150mm wide on both sides of the corner making sure that the compound completely fills the void behind the bead and covers all perforations. Allow at least 24 hours to dry. 2. Scrape off or sand any lumps or ridges and apply a second coat of compound about 200mm wide using a 200mm broad knife, blending the outer edges of the compound to the plasterboard. Allow at least 24 hours to dry.3. Using a 300mm broad knife apply the final coat of compound about 300mm wide on both sides of the corner. Ensure the compound is smooth and completely fills the surface to the outer face of the protruding metal nib. Smooth the outer edges of the compound with a broad knife.
- The Corner, Firestop, Sandpaper, butt joint