Indoor lime-cement plaster SR 7

Base

• The substrate structure must be more than +10°C. 
• Concrete substrate, block surface, lightweight concrete, sandlime brick or burnt bricks.
• The substrate must be clean, solid and dust-free. The substrate must be sufficiently hard, immobile and load-bearing.
• Loose layers, cement paste and any other impurities have been removed mechanically to ensure adhesion between Indoor lime-cement plaster SR 7 and the substrate. 
• Any smooth substrates are roughened to ensure adhesion.
• If necessary, use a plaster net for reinforcement between two different substrate materials. The net can also reduce surface cracking if the substrate material is already cracked. Nevertheless, it must always be checked that cracking is not the result of movement of the building frame.

Priming

• The substrate must be sufficiently damp before indoor lime-cement plaster SR 7 is applied.  
• The substrate is dampened with water to prevent the water in the indoor lime-cement plaster from being absorbed too quickly into the substrate. The indoor lime-cement plaster must remain damp during the hardening, so that the hardening reaction takes place correctly and the desired hardness is obtained. Having an initial matt damp surface prevents plastic cracking and the surface from coming off the substrate. There may be no water drops on the substrate. 
• Liquid Fescon adhesive primers can be used with SR 7 if necessary.
• In renovation sites, where the substrate is very dry and absorbent, we recommend multiple rounds of dampening or adhesion priming.

Work instructions

• The work site must be protected from strong winds, sunshine and rain.
• During straightening and when the indoor lime-cement plaster is hardening, the indoor temperature must be +10°C…+25°C.
• A sack (20 kg) of dry powder is mixed with 4.8–5.2 litres of clean water. You should not add to the maximum amount, at least in the beginning. The indoor lime-cement plaster has the right amount of water when the paste does not flow on the surface to be straightened.
• The amount of water must be as instructed in the product card. Deviating from the recommended amount of water has an adverse effect on the indoor lime-cement plaster’s drying time, strength properties, increases the bleeding risk, affects the strength development, and weakens workability. 
• Indoor lime-cement plaster SR 7 is mixed carefully and for long enough to create a uniform paste (using, for example, a mixing paddle connected to a power drill, or an automatic or continuous mixer).  
• When using a plaster mixing paddle, allow the paste to rest for 2–5 minutes, then mix briefly again and check the correct amount of water.
• Indoor lime-cement plaster SR 7 is applied on the substrate either by spraying or with a steel trowel. 
• The surface is smoothed with a steel trowel to the desired quality. 
• Surfaces are straightened using guide rails or planks along which the straightedge is run. When adjusting corners, install a guide plank along which you can apply the indoor lime-cement plaster neatly.
• On large surfaces, the recommended layer thickness is 5–30 mm. The best result is obtained by first spraying a thin layer of plaster, followed by a spray to the desired thickness in accordance with the wet-on-wet principle. 
• Thicker layers are created as multiple thinner layers, allowing the previous layer’s surface to remain coarse and to dry for about 24 hours before applying the next layer.  When filling holes, the maximum depth can be 50 mm. 
• Can be levelled after about 24 hours. 
• Workable for about 30 minutes to one hour after adding water.
• When finished working, wash the tools immediately with water.
• Any dried Indoor lime-cement plaster SR 7 is removed mechanically.

Covering

• Indoor lime-cement plaster SR 7 can be waterproofed immediately with Fescon waterproofing products. 
• Can be filled over with suitable Fescon wall fillers.
• Indoor lime-cement plaster can be covered directly with ceramic tiles.
• Check the humidity of the entire wall structure before installing any coating or waterproofing.
• Indoor lime-cement plaster may not be left without coating for more than one month as it may crack and break off.
• In order for indoor lime-cement plaster to dry well, the relative humidity of indoor air must be less than 50% and the temperature more than +20°C. Poor conditions slow down the development of indoor lime-cement plaster’s strength properties and extend the drying period.

Storage and handling of waste
See the separate storage and disposal instructions https://www.fescon.fi/en/material-bank