Ballymun Regeneration Limited has begun legal proceedings against quarry owners Irish Asphalt and its parent company Lagan Group in relation to 124 social housing units with pyrite problems.
Works to rectify the Sillogue Four development in Ballymun will cost €10.5m.
The social housing development was 97% finished and almost ready for people to move into three years ago, when Ballymun Regeneration Limited (BRL) discovered problems.
Initially believed to be settling cracks, scientific testing proved the large gaps were caused by a pyrite problem in the stone fill underneath the poured concrete.
BRL - a Dublin City Council owned company - stopped construction and last year began an extensive process to rectify the entire development.
This involves cutting up and removing the concrete floors and footpaths, and then removing the stone fill below and replacing it.
It plans to have 60 housing units completed by the end of this year, and the rest finished by next summer.
BRL says all of the stone in question came from the Bay Lane quarry in Blanchardstown.
BRL has decided to sue Irish Alphalt and the Lagan Group has served legal papers on them in relation to problems at Sillogue Four.
Meanwhile, two other Ballymun regeneration housing schemes are currently being tested to determine whether pyrite is causing damage there - the developments are Carton Terrace and Owensilla.
Elsewhere, Dublin City Council has identified some of its developments which have pyrite problems:
- Avila Park in Finglas, where there are six units specifically for members of the Travelling community
- Taffes Place in Ballybough, where 20 of the 78 units in the development are affected
- Griffith Heights where 35 affordable housing units have pyrite problems, as do 15 units of senior citizens’ accommodation at Griffith Close.
The council says it is currently engaged in negotiations and legal discussions with the contractors involved in those locations, and says it is not possible to determine with certainty the timelines for completion of necessary works to rectify the problems.
