Cairn Homes has secured planning permission for 107 new apartments at its Marianella development in Rathgar, Dublin 6.

The listed housebuilder originally obtained permission in July 2017 to construct 22 houses on a 0.95ha (2.35ac) portion of its overall 3.28ha (8.11ac) Marianella site, which it spent about €43 million to acquire in 2015. The recent surge in popularity of apartments, which has been largely driven by the build-to-rent market, resulted in Cairn seeking permission just over a year later for two apartment blocks to replace the permitted houses.

Although it is clearly a more efficient use of scarce development land, the decision to allow almost five times as many units to be built in the final phase of the scheme has provoked the anger of residents at the Rathgar scheme, where more than 200 homes have been built so far.

Last December it was reported that they had raised €11,000 to fight Cairn’s plans for new apartments. Residents were particularly concerned that, at less than one per unit, the number of parking spaces suggested the entire scheme might be sold to an investor as build-to-rent.

The residents hired a planner, a barrister and a photographer to help them oppose the development; one resident said they would “go to the bitter end” to halt Cairn’s plans should planning permission be granted.

Cairn insisted it had not at that time begun negotiations to sell the block, but now that permission has been granted it will have to choose whether to sell the units individually, as it has done so far in the development, or to sell all of them to an investor.

An Bord Pleanála’s decision to grant permission is Cairn’s second recent big win under the fast-track-planning provisions, following the decision to allow the company to build 221 homes on the upmarket Cross Avenue in Blackrock, south Co Dublin. Chesterfield House, the former home of the late businessman Tom Roche, will be replaced by 214 apartments and seven houses.