Knowing the approximate drying time of the plaster mixture, it is possible to plan the beginning of the painting finish and avoid work defects. It is impossible to accurately calculate how long the plaster dries, since it depends on a number of factors, but you can find out the approximate time when it is allowed to begin the putty of the plastered surface.
What affects the rate of drying
Faster or slower the drying of the plaster depends on:
- Layer thickness
- Type of mixture,
- Temperature and humidity in the room (outside for the facade),
- Material walls.
The thicker the layer, the slower the solution dries. However, this rule cannot be applied to all types of solution, since the compositions of the mixtures are different. Regarding the type of plaster, the plaster-filled formulations dry faster, and the polymer and cool additives more slowly.
The laws of physics act on the rate of drying and depending on temperature and humidity. The higher the temperature, the faster the moisture evaporates from the plaster, the sooner the mortar sets and dries. At high humidity in the room or on the street, the plaster hardens more slowly and vice versa.
Influences drying time and wall material. For example, mortar dries faster on brick walls, as these materials have good absorption. In short, the higher the absorption of the base, the faster the plaster layer dries.
Is it possible to speed up the process
Each plaster, under standard conditions of application, has its own drying time, but drying can be accelerated by using heaters (heating heater + fan). The flow of warm air directed to the wall, promotes the rapid evaporation of moisture from the solution, and therefore brings the layer to the ready time. However, it is not always wise to use this method, as with artificial acceleration of drying, cracks may appear on the wall surface.
Heating the room is advisable only in cases where the temperature in the room does not reach the rate specified by the manufacturer of the plaster.
Another way to accelerate drying is to add gypsum to a lime-cement mortar. This option is suitable for plastering walls in rooms with normal humidity, gypsum is not used for finishing the bath, basement and facade.
In the premises, to speed up the drying, open the windows - this will decrease the humidity of the air.
Remember two important rules:
- Accelerate drying due to plaster and warming the walls only in extreme cases, as this will worsen the quality of the finish.
- Do not confuse the setting time and complete drying! After setting, the solution hardens and does not stick to the hand, but begins to further finish the walls only after the plaster has dried, when excess moisture has left the solution (the norm is 8%).
Drying speed of various plasters
Under standard conditions of using lime-cement mixture (humidity 60-80%, temperature 15-25 degrees), a solution 2 cm thick on a brick wall sets in 2-3 hours, and the total drying time is 24 hours.
Read the manufacturers advice on the packaging with plaster.
For internal plasters there is a correct rule for checking their readiness for finishing. If dark stains remain on the wall when water drops on it, the mixture has dried - it already absorbs moisture, which means it has its own low humidity.
After the plaster has dried, you can start painting work.