Mica remediation protocol to be reviewed amid concerns over new mineral

No mention of pyrrhotite in protocol ‘alarming’, says group representative

Muscovite mica, a mineral, has led to apparent defects in building blocks used in at least 5,000 homes in the northwest, causing cracks to open up in thousands of buildings. Photograph: Joe Dunne
Muscovite mica, a mineral, has led to apparent defects in building blocks used in at least 5,000 homes in the northwest, causing cracks to open up in thousands of buildings. Photograph: Joe Dunne

A national protocol that underpins the remediation scheme for homeowners affected by mica and pyrite is to be reviewed amid concerns about the existence of other deleterious materials in the properties.

A number of homeowners in Donegal have been alerted to the presence of pyrrhotite in their blocks, on top of the existence of Mica.

Pyrrhotite, a naturally occurring iron sulfide which can react with oxygen and water and lead to cracking and swelling in concrete, has been implicated internationally in the deterioration of houses in Connecticut and Quebec.

Muscovite mica, a mineral, has led to apparent defects in building blocks used in at least 5,000 homes in the northwest, causing cracks to open up in thousands of buildings. The Cabinet last year approved an enhanced scheme to cover repairs or rebuilding for affected homes.

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A review is now being carried out into the national standard, known as IS 465, after Opposition politicians and campaigners raised concerns in recent weeks about pyrrhotite.

The protocol is used by engineers and geologists to assess the damage in properties where the concrete blocks are suspected to contain mica or pyrite.

Campaigners say that they fear there may eventually be homes that have the outer leaf remediated under the Government scheme but still have the inner blockwork or foundations intact, which could contain pyrrhotite.

They say pyrrhotite must now also be considered as a relevant deleterious material when it comes to choosing remedial options, and that the protocol needs to be revised to include it along with mica and pyrite.

‘Undermined’

Mica Action Group representative Eileen Doherty said the situation was “alarming” as “there is no mention of pyrrhotite in the protocol, and there is no consideration for multiple minerals being found in the blocks and therefore the remediation options put forward in this protocol, such as outer leaf replacement, are completely undermined”.

“This sounds incredibly technical but in simple terms this means that we have completely lost confidence in the protocol the Government has developed to guide the fix of our homes.

“If they have not even considered the combination of these deleterious minerals and in fact have not even referenced one of the minerals at all, how are we supposed to have any faith that the ‘fixes’ put forward in this protocol are appropriate.”

Minister for Housing Darragh O’Brien has confirmed that a review will take place of the protocol underpinning the remediation scheme.

“Officials from my department have since met with the National Standards Authority of Ireland (NSAI) and other relevant stakeholders and I can confirm that a review of the standard will be carried out,” he said in response to questions from Sinn Féin TD Pádraig Mac Lochlainn and Independent TD Thomas Pringle.

“Meetings are ongoing between the relevant stakeholders to consider and finalise the scope of the review required, what further research is necessary and the timescale for completion of the review.”

A spokesman for the NSAI told The Irish Times that its approach to any revision “is through an evidence-based and scientifically informed process”.

The NSAI said that to change the protocol, a considerable amount of relevant data will be needed including engineers reports, petrographic reports (reports that examine failures in concrete and rocks), while material tests must be reviewed.

“In addition, the need for further research has been identified.”

The Cabinet last year approved an enhanced scheme to cover repairs or rebuilding for thousands of homes affected by pyrite and mica in Donegal and Mayo.

It includes a €420,000 cap on the level of support on offer, up from €247,500 under a previous version of the scheme.

Jennifer Bray

Jennifer Bray

Jennifer Bray is a Political Correspondent with The Irish Times