The Northern Ireland Valuation Tribunal has ruled in favour of a Londonderry homeowner in a rates dispute, reducing the capital value of his unfinished property from £200,000 to £140,000 - a 30% reduction - after finding that a waterproofing failure affecting below-ground external walls warranted a greater allowance than the Commissioner of Valuation had applied.

The property at 58 Victoria Gate, Tamnymore, Londonderry BT47 2TP is a detached three-storey dwelling constructed around 2022. It sits on a steep site where part of the ground floor at the rear is one storey below the back garden level, incorporating basement-type construction with concrete walls and a waterproof tanking system. The appellant, Damien Villa, argued that a failure in that tanking system had caused water to penetrate the external walls, making them damp, and that Building Control would not issue a Completion Certificate until the fault was rectified, preventing the property from being occupied or sold.

The rating history shows that a 90-day Completion Notice was issued by the District Valuer on 25 September 2023. An appeal by Villa against that notice was dismissed by the Commissioner of Valuation on 9 February 2024, which determined that the property could reasonably have been completed by 25 December 2023. The property was entered into the Valuation List at a capital value of £200,000 effective from that date. Following a further appeal, the Commissioner of Valuation reduced the capital value to £160,000 on 27 May 2025, applying a 20% allowance for the external repair issue. Villa appealed that figure to the tribunal.

At a remote hearing conducted by WebEx on 31 March 2026, Villa represented himself. The Commissioner of Valuation was represented by valuer Timothy Kelly MRICS and senior valuer Joanne Attwood. Villa described excavation works being carried out in stages to preserve the structural integrity of the building, with flooring removed at ground level to address the damp problem. He estimated the total cost of remediation works at around £40,000, including a quote of between £24,000 and £26,000 from contractors Stronghold Preservation for an internal cavity drainage solution. He noted that Rentokil had also been consulted.

The tribunal, chaired by President James Leonard and including members Mr A Tough FRICS and Ms N McCartan, upheld the validity of the Completion Notice. It found that Villa had not presented sufficient evidence to challenge the respondent's position that the property could have been completed within the period specified. The tribunal also confirmed that personal or financial circumstances affecting the pace of works could not be taken into account in its determination.

On the question of the capital value reduction, the tribunal accepted the base figure of £200,000 as correctly assessed, supported by four comparable properties in the same development with capital values ranging from £195,000 to £210,000. It noted that while the respondent's concession of a 20% reduction was not itself disputed, the property's recent construction distinguished it from older buildings considered in comparable cases. The tribunal determined that a 30% reduction was appropriate, arriving at an adjusted capital value of £140,000. The tribunal ordered the Valuation List to be amended accordingly.

The decision was recorded and issued to the parties on 20 April 2026.