The Stages of Plastering
Apply 1st coat of finish plaster approx 2mm thick
Aim – flat even coat that is not bulging. Trowel marks and ridges no problem
How - Gradually flattening trowel loaded with plaster.
No plaster is applied
Aim – to flatten off 1st coat. Ensure all bulges and ridges are flattened. If the wall has a few areas that are a bit wet, where the plaster hasn't firmed up as much as the majority of the wall, then it may be that you leave a few ridges in. This isn't too much of a concern as at least they are wet enough to be dispersed when applying the 2nd coat.
When - Can commence when 1st coat has firmed up.
How - Firm pressure applied with a clean trowel. Leading edge of trowel approx 10 – 15mm away from wall.
Apply 2nd coat of plaster approximately 1mm thick
Aim – Flat even coat without too many holes
When - straight after completion of stage 2
How – As with 1st coat but with more pressure. This coat is half the thickness so half the amount of plaster on your trowel will cover the same area. If firm pressure is applied to the trowel then the plaster will be pushed evenly on to the wall. If not then holes will be visible and a little more pressure may be required. Don't worry about filling every hole as the complete next stage is responsible for holes – but do your best and the next one will be easy. If it is taking along time to get a finish with no holes then it is better to move across the wall a bit quicker and be content to fill the small holes in the next stage. Otherwise if it starts to firm up too quickly then you may find that some of the wall is perfect and the other terrible.
If during any of the following stages the plaster is too dry and cannot be 'worked' properly then flicking a little water on the wall with your brush should liven it up a little. If the whole wall is really dry due to the fact that you may not have fully controlled the suction then sometimes it can be easier to flatten the whole wall, soak it with some water and apply another coat of plaster.
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