Setting Coat to Plasterboard Ceiling
For the setting coat, you should use a plaster recommended by the manufacturer. A scrim will be needed for reinforcing joints between the boards to reduce the risk of cracks appearing. Dry lining paper tape and self adhesive glass fibre mesh tape are other materials used to reinforce joins. Cotton and bandage scrims can be used but they are more traditional methods. Apply scrim, cotton and tape. The scrims need to be cut to the correct length, they should not overlap and should not be any closer than 25 mm. A strip of board finish should be placed over each joint one at a time. Next you will need to lay the scrim over the trowel and squeeze the scrim in to the plaster right to the background. Go back over the scrim with a small amount of plaster on the trowel making sure the scrim is completely covered. Self adhesive tape When using self adhesive tape, the plasterboard must be clean and free from any dust or the tape will not stick properly. First you will need to cut the tape to the length that you need and then you can stick it to the plasterboard joints. The tape will then need to be covered in plaster, Ceiling Once the scrims have been cut and applied, a band the length of the trowel should be spread up to the ceiling and the wall line up against the scrim. The first application should go between the scrims, covering the ceiling starting from the left side. Another coat of plaster should be applied immediately using a float over the entire ceiling, this includes the scrims. The second application is applied in order to help straighten up the scrims. When the second starts to dry, apply another another coat This is the last coat so there should be no lines or marks left. To finish the walls, trowel up the final coat. The walls are done in the exact same way as the ceiling.