expenditure of a revenue nature is allowed in the year of assessment, i.e. expenditure that isn't of major nature. this would include repairs, small purchases of fixtures and fittings etc. This would not be allowed in a CGT comp
expenditure of a capital nature such as hiring someone to build an extension which ultimately leads to the enhancement in value is allowable in a CGT comp.
indexation ceased for houses purchased after 31 December 2002. however a sale of a house in 2005 when originally purchased pre Dec 02, will avail of indexation on both original cost of house and any expenditure of a capital nature at the 02 rateof indexation.
expenses such as professional fees are allowed both for the sale and also can be used as addional original costs (these also can be indexed).
check the revenue website for the appropriate index.
disposals of property between January and September must be included as a payment of CGT by 31 October. anything after that can be paid by 31 January following