The following table was first published by the SMA and been recently updated. The SMA offers this as a general troubleshooting guide of problems or unwanted conditions found or related to portland cement plaster/stucco walls. The chart lists the conditions, possible causes, prevention’s or possible remedies. Not all of these conditions are in the control of the plastering contractor. This chart can also be used as a pre-installation discussion guide for plaster/stucco projects to help avoid unwanted conditions\
PORTLAND PLASTER CEMENT TROUBLESHOOTING – CAUSE AND CURE
|CONDITION||CAUSE||PREVENTION OR POSSIBLE REMEDY|
|Cement fails to set||Do not use old cement, shelf life is typically|
|Excessive aggregate||Measure aggregate (calibrated box) to establish|
proper shovel count or use pre-blended mix.
|Inadequate damp curing||Keep damp for 24 hours. Fresh soft plaster|
may be redeemed by continuous wetting until
proper set and hardness are obtained.
|Inadequate or excessive mixing||After all materials are in the mixer, minimum|
two (2) but not more than ten (10) minutes.
|SOFT PLASTER||Impurities in water or aggregate||Test water and aggregate. Use washed plaster|