- 1). Build a plaster wall on a base of masonry like concrete or concrete block, cement fiber board, special gypsum plasterboard or wooden wall sheathing. Install cement fiber board with galvanized screws or nails fastened to wall studs with a screw gun or hammer. Hang gypsum board much like drywall panels, with galvanized nails driven into studs; it differs from conventional drywall only in the facing, which is specially made to hold plaster.
- 2). Cover a wood-sheathed wall with a waterproof membrane stapled to the wood with a construction stapler. Place a layer of metal lath over the wall, fastened with galvanized nails to the studs through the sheathing. Lay it tight against the waterproofing.
- 3). Spread a first "scratch" coat over the base wall of masonry, cement fiber or metal lath with a rectangular mason's trowel. Make this coat about three-eighths inch thick. Scratch the surface with horizontal lines once the plaster has begun to set, using the notched edge of the trowel, a stiff bristle broom or a leaf rake. Let that coat dry at least 48 hours, keeping it slightly moist as it sets up. Skip this step with plasterboard.
- 4). Add a second "brown" coat, with a little extra sand in the plaster mix, over the scratch coat. Make this the first coat on plasterboard, which will bond to the plaster fine because it is made of gypsum. Apply it three-eighths inch thick with a trowel and smooth or "screed" it with a long board or straight edge pulled down the wall to create a smooth, flat surface. Let it cure at least 24 hours.
- 5). Finish building the plaster wall with a final top coat, spread about one eighth inch thick. Dampen the brown coat slightly before applying the finish coat. Smooth the finish coat or texture it with swirls, dimples or any other appealing pattern. Use the flat side of a trowel to pull plaster up into small peaks, then smooth those peaks to create a "popcorn" effect.
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