Why these plastering surface cracks will occur pls explain about that

[Ganeshnannuri]

Good morning,
Why these plastering surface cracks will occur pls explain about that

 

[paresh bhatt]

This Shrinkage Cracks.... To avoid this cracks, use only wet mortar for plaster

 

[archdevil]

This Shrinkage Cracks.... To avoid this cracks, use only wet mortar for plaster

 

[archdevil]

improper cuing to the brick work results the brick work absorb water from the plaster resulting shrinkage creaks. try to avoid plastering until and unless the brick work is cured for a minimum period of 7 days, after proper curing do the plaster , you wont find thee cracks .

 

[Valmiki]

Good morning,
Why these plastering surface cracks will occur pls explain about that
View attachment 3176

Hi,

This Early Cracks in Plasters unpleasant but they are indicative to something wrong in material of cement and sand selection or the procedure used for application very fine plaster cement slurry finish. The most Common defects observed in Plasters are Plastic shrinkage cracks & drying shrinkage cracks, to understand the reasons of occurrence of these cracks in Plaster and steps to be taken to minimise them.
Plastic Shrinkage crack as your photo this results when an excessive amount of water is lost from the plaster in the first few hours after its application. When the cracks are noticed while the plaster is still plastic (yet to harden), they are often floated (finished to make it look like smooth) and closed at site. But its not a good practise as these cracks reappear some time in near future.

How to avoid this cracks

• Protect the plaster from sun & wind to avoid drying too quickly, initiate plastering timing to avoid direct sunlight and strong wind on plastering surface
• Saturate the masonry wall adequately with water before plastering. This will avoid the brick work from absorbing the water in plaster
• Start curing as early as possible if the weather is hot, windy and dry (less humid)
• Do not use sand which lacks fine material (less than 15% by mass passing 0.150mm sieve or use Sand of Fineness modulus beteween 2.4 to 2.6)
• If sand lacks fine material then add some lime into cement plaster.

Another type of crack is
Drying shrinkage result may be also as show in your photo is due to moisture loss after the plaster has hardened. Plaster is bound to shrink and crack. Usually, Plaster applied in layers that are too thick (i.e., >20mm) will tend to crack in this way. These cracks are normally stable and can be filled with crack repair mortar and painted over.

It is possible to reduce drying shrinkage and hence the resultant cracks.

• Do not use very fine sand requiring more water (Don”t use sand with Fineness modulus < 2.2). We recommend usage of plaster Sand for Plastering Purposes.
• Do not use rich plaster mix (with High Cement Content). Use cement motar mix of 1:4 or below depending on the quality of Sand
• Avoid OPC preferably used flyash blended cement (PPC). PPC has less heat of hydration so will results in lesser cracks as compared to OPC
• Use water reducing admixture in plaster mix
• Avoid very thick plaster layers (i.e., thickness more than 15mm). If you need more thickness, then build plaster in layers of 12-15 mm with a gap of 3 days
• Do the curing immediately after the setting time of plaster mortar for a period of minimum of 07 days

 

[Ganeshnannuri]

Hi,

This Early Cracks in Plasters unpleasant but they are indicative to something wrong in material of cement and sand selection or the procedure used for application very fine plaster cement slurry finish. The most Common defects observed in Plasters are Plastic shrinkage cracks & drying shrinkage cracks, to understand the reasons of occurrence of these cracks in Plaster and steps to be taken to minimise them.
Plastic Shrinkage crack as your photo this results when an excessive amount of water is lost from the plaster in the first few hours after its application. When the cracks are noticed while the plaster is still plastic (yet to harden), they are often floated (finished to make it look like smooth) and closed at site. But its not a good practise as these cracks reappear some time in near future.

How to avoid this cracks

• Protect the plaster from sun & wind to avoid drying too quickly, initiate plastering timing to avoid direct sunlight and strong wind on plastering surface
• Saturate the masonry wall adequately with water before plastering. This will avoid the brick work from absorbing the water in plaster
• Start curing as early as possible if the weather is hot, windy and dry (less humid)
• Do not use sand which lacks fine material (less than 15% by mass passing 0.150mm sieve or use Sand of Fineness modulus beteween 2.4 to 2.6)
• If sand lacks fine material then add some lime into cement plaster.

Another type of crack is
Drying shrinkage result may be also as show in your photo is due to moisture loss after the plaster has hardened. Plaster is bound to shrink and crack. Usually, Plaster applied in layers that are too thick (i.e., >20mm) will tend to crack in this way. These cracks are normally stable and can be filled with crack repair mortar and painted over.

It is possible to reduce drying shrinkage and hence the resultant cracks.

• Do not use very fine sand requiring more water (Don”t use sand with Fineness modulus < 2.2). We recommend usage of plaster Sand for Plastering Purposes.
• Do not use rich plaster mix (with High Cement Content). Use cement motar mix of 1:4 or below depending on the quality of Sand
• Avoid OPC preferably used flyash blended cement (PPC). PPC has less heat of hydration so will results in lesser cracks as compared to OPC
• Use water reducing admixture in plaster mix
• Avoid very thick plaster layers (i.e., thickness more than 15mm). If you need more thickness, then build plaster in layers of 12-15 mm with a gap of 3 days
• Do the curing immediately after the setting time of plaster mortar for a period of minimum of 07 days

Hi,

This Early Cracks in Plasters unpleasant but they are indicative to something wrong in material of cement and sand selection or the procedure used for application very fine plaster cement slurry finish. The most Common defects observed in Plasters are Plastic shrinkage cracks & drying shrinkage cracks, to understand the reasons of occurrence of these cracks in Plaster and steps to be taken to minimise them.
Plastic Shrinkage crack as your photo this results when an excessive amount of water is lost from the plaster in the first few hours after its application. When the cracks are noticed while the plaster is still plastic (yet to harden), they are often floated (finished to make it look like smooth) and closed at site. But its not a good practise as these cracks reappear some time in near future.

How to avoid this cracks

• Protect the plaster from sun & wind to avoid drying too quickly, initiate plastering timing to avoid direct sunlight and strong wind on plastering surface
• Saturate the masonry wall adequately with water before plastering. This will avoid the brick work from absorbing the water in plaster
• Start curing as early as possible if the weather is hot, windy and dry (less humid)
• Do not use sand which lacks fine material (less than 15% by mass passing 0.150mm sieve or use Sand of Fineness modulus beteween 2.4 to 2.6)
• If sand lacks fine material then add some lime into cement plaster.

Another type of crack is
Drying shrinkage result may be also as show in your photo is due to moisture loss after the plaster has hardened. Plaster is bound to shrink and crack. Usually, Plaster applied in layers that are too thick (i.e., >20mm) will tend to crack in this way. These cracks are normally stable and can be filled with crack repair mortar and painted over.

It is possible to reduce drying shrinkage and hence the resultant cracks.

• Do not use very fine sand requiring more water (Don”t use sand with Fineness modulus < 2.2). We recommend usage of plaster Sand for Plastering Purposes.
• Do not use rich plaster mix (with High Cement Content). Use cement motar mix of 1:4 or below depending on the quality of Sand
• Avoid OPC preferably used flyash blended cement (PPC). PPC has less heat of hydration so will results in lesser cracks as compared to OPC
• Use water reducing admixture in plaster mix
• Avoid very thick plaster layers (i.e., thickness more than 15mm). If you need more thickness, then build plaster in layers of 12-15 mm with a gap of 3 days
• Do the curing immediately after the setting time of plaster mortar for a period of minimum of 07 days

Thanks valmiki ji

 

[Sachin Hipparkar]

Hi,

This Early Cracks in Plasters unpleasant but they are indicative to something wrong in material of cement and sand selection or the procedure used for application very fine plaster cement slurry finish. The most Common defects observed in Plasters are Plastic shrinkage cracks & drying shrinkage cracks, to understand the reasons of occurrence of these cracks in Plaster and steps to be taken to minimise them.
Plastic Shrinkage crack as your photo this results when an excessive amount of water is lost from the plaster in the first few hours after its application. When the cracks are noticed while the plaster is still plastic (yet to harden), they are often floated (finished to make it look like smooth) and closed at site. But its not a good practise as these cracks reappear some time in near future.

How to avoid this cracks

• Protect the plaster from sun & wind to avoid drying too quickly, initiate plastering timing to avoid direct sunlight and strong wind on plastering surface
• Saturate the masonry wall adequately with water before plastering. This will avoid the brick work from absorbing the water in plaster
• Start curing as early as possible if the weather is hot, windy and dry (less humid)
• Do not use sand which lacks fine material (less than 15% by mass passing 0.150mm sieve or use Sand of Fineness modulus beteween 2.4 to 2.6)
• If sand lacks fine material then add some lime into cement plaster.

Another type of crack is
Drying shrinkage result may be also as show in your photo is due to moisture loss after the plaster has hardened. Plaster is bound to shrink and crack. Usually, Plaster applied in layers that are too thick (i.e., >20mm) will tend to crack in this way. These cracks are normally stable and can be filled with crack repair mortar and painted over.

It is possible to reduce drying shrinkage and hence the resultant cracks.

• Do not use very fine sand requiring more water (Don”t use sand with Fineness modulus < 2.2). We recommend usage of plaster Sand for Plastering Purposes.
• Do not use rich plaster mix (with High Cement Content). Use cement motar mix of 1:4 or below depending on the quality of Sand
• Avoid OPC preferably used flyash blended cement (PPC). PPC has less heat of hydration so will results in lesser cracks as compared to OPC
• Use water reducing admixture in plaster mix
• Avoid very thick plaster layers (i.e., thickness more than 15mm). If you need more thickness, then build plaster in layers of 12-15 mm with a gap of 3 days
• Do the curing immediately after the setting time of plaster mortar for a period of minimum of 07 days

plaster ke samay Mistry suka cement use karte hai. Kya wo Sahi hai use karnna

 

[Valmiki]

plaster ke samay Mistry suka cement use karte hai. Kya wo Sahi hai use karnna

No never do finish with cement dry are wet as cement is shrinkage material so it will cause minute cracks which is visible during curring of wall plaster. Better to have sponge finish plaster face.