well, if you have trees or any high posts then cats can go up the roof. my parents cats do go up the roof from the fence wall, climb to awning then the roof. anyway, if you do catproofing properly, then your cats won't go up the roof if there are no accessible high points

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Cats are precious creatures that enhance one's life. Respect them, take good care of them, and above all, love them. Their love, affection and attention will be your reward.