There are many advantages in joint family rather having disadvantages but u have asked disadvantages so I m giving u:
1-You need to have a big house.
2-You need to make more dinner.
3-You need to give your time with each one of them which can take more efforts.
There are many disadvantages of having a big family are as follow ;-
1. The only earning man has a lot of pressure about the income & financial situation of the family
2. There is a lack of  the privacy between family members.
3. you need to make a big investement in making houses for a big joint family

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