Cracks of any size in a cement-based render should be tackled at an early stage as they encourage water to be drawn into the underlying material as a result of capillary action.
Dylid ymdrin â chraciau o unrhyw faint mewn rendr sment yn gynnar am y gall dŵr gael ei dynnu i mewn i'r deunydd sylfaenol drwyddynt o ganlyniad i gapilaredd.