The land and buildings are separable assets and are accounted for separately, even
when they are acquired together. With some exceptions, such as quarries and
sites used for landfills, land has an unlimited useful life and therefore is not
depreciated. Buildings have a limited useful life and therefore are depreciable
assets. An increase in the value of the land on which a building stands does
not affect the determination of the depreciable amount of the building
Now my question is what is the criteria to separate the cost of land and building, in the case where the single transaction is undertaken and what if it cant be separated, then it will be ok to start depreciating the entire amount?
You should separate them, using relative fair values as the basis for separation. If the building is a total ruin, you can assign the entire transaction price to the land.
See https://ifrscommunity.com/knowledge-bas ... -buildings