Land value for depreciation

If I bought a property with the intention of renting it and completed renovated it, do I subtract out the land value rate when first purchased (2018) or after the renovations are complete and the house is ready and available to be rented (2019)?  Note:  The building value was less than the land value when first purchased and the assessment was very low.  After the entire house was renovated, the assessment went up significantly and the building value is much higher than the land value.  I'm trying to determine the basis of the house to depreciate but am not sure at which point in time to use land value to get my net basis: 2018 value or 2019 value?

Thank you.