Now the frame is up and the electrical and plumbing work has been roughed in its time to do the plastering. In this house there are two types of plastering and two seperate trades doing that plastering. The first type of plastering is dry work using plasterboard that is either fixed to the studwork, to battens or directly stuck to existing walls. Where new studwork occurs the plasterboard is nailed to it in horizontal panels. At the old house metal battens were used where the wall was large, on small areas the plasterboard was ‘direct fixed’.
The battens are fixed to the wall with small cleats. The cleats have ‘teeth’ on arms at different that are at different points away from the wall that allow the battens to be placed closer or further from the wall. Minor adjustments are made by bending the arms towards the wall so that the battens can be fixed plumb despite walls being uneven.
Where plasterboard is direct fixed the existing wall is scrapped back and cleaned at regular points so that blobs of adhesive plaster can be smeared on the wall (at approximately 450mm centres). The board is them pressed into position till it is plumb. This type of fixing was suitable for small bits of wall – not larger areas.
At the base of the new walls P50 stopping beads were fixed to create a 10mm rebate between the walls and the floors. This gives a great effect of lightness and flow (described in the ‘niblessness’ post). At corners metal trims are used to provide a crisp straight edge and to protect the corners. Finally wet plaster was smeared between boards and at the trims to join the plasterwork into a coherent whole. The plaster is then sanded back to give a smooth, continuous surface.
The other plastering was ‘rendering’ or wet plaster work. This is the traditional method of solid plastering over masonry to give a solid plaster finish. We did this in the old building where old plaster was disturbed at opened arches, switches, loose plaster and where skirting had been removed. This involved applying a grey cement, sand mix as a filler (for about 20m) then applying a plaster topcoat as a finish. The effect of this raw plaster looks great – a soft white, handmade look. Unfortunately it was going to be painted to match the rest of the house.
We also had to plaster over textured walls that had been surfaced to hide imperfections in the walls prior to selling the house. To do this we had to paint the walls with Boncote, a type of glue that creates a strong surface capable of being plastered over. Then a topcoat was applied.