Find out why primers are crucial before skim coat application.
skim coat application 2 hours after priming
room temperature 5 to 25oC
a bucket for mixing
electric grinding tools
Reasons for priming before skim coats
When substrate was checked and accepted, all cracks and holes are filled inn, surface is clean and vacuumed it is time for priming with suitable product. Why priming is needed?
- To reduce water absorption of the substrate.
- To increase strength of the substrate.
- To increase the adhesion to the substrate.
- To protect substrate against moisture.
Substrates for skim coats
All kinds of skim coats can be applied on load-bearing substrates that are dry and free from grease, bitumen, dust, loose plaster grains and other substances decreasing adhesion:
- cement and cement-lime plasters (age above 28 days, moisture ≤ 4%), concrete (age above 3 months, moisture ≤ 4%) – primed with Ceresit IN 10 primer or Ceresit CT 17 diluted with water 1:1,
- gypsum substrates with moisture content below 1% – primed with Ceresit IN 10 primer or Ceresit CT 17 diluted with water 1:1,
- gypsum-fibre boards and plaster boards, fixed according to the recommendations of board manufacturers – primed with Ceresit IN 10 primer or Ceresit CT 17 diluted with water 1:1,
- paint coats – strong, highly adhesive.
How to tackle uneven substrate?
If substrate is uneven at first glance, apply a regular plaster or fix a gypsum board on the substrate before skim coat application.
In case of peeling paint or shiny oil base paint, fix a gypsum board or frame construction with a gypsum board.