Houses/apartments are sold off-plan, that is, before constructing the houses, they are sold on the basis of the plan.

Answer

Buying a house/apartment 'off plan' is not permissible. The item of sale (mabee') is non-existent. Furthermore, this satanic scheme has come with massive fraud. Numerous people have lost their money – millions – in these schemes. Muftis who are morons halaalize this wicked scheme on the basis of Istisnaa'. They must apply their hearts to their brains, and endeavour to ascertain the reality on the ground before vomiting zigzag fatwas.