Builders who had constructed 25 new homes for people on a council housing list yesterday began to take out doors, windows and any other reusable items as six of the houses were taken down because they were built with pyrite blocks.

Tony Gilmore, a director of the North and East Housing Association (NEHA) who are providing the houses on land owned by Louth County Council at Moneymore, Drogheda, confirmed that some of the blocks used to build walls in six of the semi-detached houses "were found to be infected".

He said the report on the six houses was based on tests that the NEHA technical manager had requested.

Pyrite is a mineral which reacts with moisture and expands, causing cracks and movement of walls.

A more extensive report on the remaining 19 houses in the scheme, which includes two wheelchair-accessible homes, is expected this week. Its findings will determine if the remaining houses will also face salvage and then demolition before being rebuilt.

"Some of these houses were in the final stages of completion and it was when the walls had been plastered that the cracks became obvious," said local councillor Imelda Munster yesterday.

Not detected sooner

She has demanded to know how the problem was not detected before April – it was only then when the scheme was in its final stages that technical experts were called in. “The chances are that if the materials with pyrite were used in the first six houses then they are in the remaining 19 ones as well.”

The houses were being built on local authority land as an extension to the 33-year-old Moneymore estate.

“This is a devastating blow when there are 1,624 people on the housing list in Drogheda,” added Ms Munster.