42 (Expressed in Trinidad and Tobago Dollars) NOTES TO THE SPECIAL PURPOSE FINANCIAL STATEMENTS 30th June 2017 4 Summary of significant accounting policies (continued) h. Property, plant and equipment (continued) Property, plant and equipment are stated at historical cost less accumulated depreciation and impairment losses except for artwork and freehold properties which are stated at valuations conducted by independent professional valuators every three years. Freehold properties were professionally valued in June 2016 using the investment method, Note 14. Subsequent costs are included in the asset’s carrying amount or recognised as a separate asset, only when it is probable that future economic benefits associated with the item will flow to NIBTT and the cost of the item can be measured reliably. All other repairs and maintenance are charged to the statement of comprehensive income during the financial period in which they are incurred. If an asset’s carrying value is increased as a result of a revaluation, the increase is credited directly to reserve under the heading revaluation reserve. If an asset’s carrying value is decreased as a result of a revaluation, the decrease is debited directly to equity to the extent of any credit balance existing in the revaluation reserve in respect of that asset. Any decrease in excess of this amount is recognised in the statement of comprehensive income. Additionally, for those assets that are revalued as at the statement of financial position date, the accumulated depreciation for the revalued assets are credited to the revaluation reserve. The accumulated depreciation for revaluated assets is therefore brought to zero. Depreciation is provided on a straight-line basis at varying rates sufficient to write-off the cost/market value respectively of the assets over their estimated useful lives. The rates used are as follows: Freehold and leasehold properties – 2% on buildings Improvements to premises: Owned – Equal annual instalments over a period of ten years. Leased – Equal annual instalments over the period of the lease. Machinery, equipment, furniture and fixtures Machinery – 7.5% - 25% Artwork and motor vehicles – 25% Gains and losses on disposal of property, plant and equipment are determined by comparing proceeds with their carrying amount and are recognised in the revenue and expenditure accounts. i. Properties being developed for sale (Inventory) Properties available for sale are carried at cost less provisions for impairment. The provision is estimated as the difference between the cost and the selling price of the units available for sale less the estimated cost to complete the units.