Public Inquiry call for defective concerete blocks scandal

There have been renewed calls for a public inquiry into defective concrete and defective concrete blocks manufactured in the Republic of Ireland and sold into the Northern Ireland market. An online petition demanding a public inquiry was launched on Wednesday. 

Homeowners in Inishowen and wider Donegal have been affected by the issue, which manifests itself in crumbling blocks and telltale cracks in walls.

More recently, Danny and Kate Rafferty from Beragh Hill Road in the Skeoge area of Derry have also discovered their home was constructed from defective concrete blocks, which originated in Donegal.

A conference on the Science and Societal Impacts of Defective Concrete, featuring international experts, was held in Letterkenny on Tuesday.

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The keynote speaker at the conference’s evening session, Scientific Insights into the Causes of Defective Concrete, Dr Andreas Leemann from the Swiss Federal Laboratories for Materials Science and Technology.

Dr Leemann said research completely contradicted the idea the blocks were damaged by frost. His conference presentation can be viewed below. 

Dr Leemann said that analysed concrete blocks suffered instead from internal sulphate attack triggered by pyrrhotite oxidation with sulphur release.

The sulphur content in the aggregates found in the analysed blocks “considerably exceeded the limit value of EN 12620, the European Standard which specifies the properties of aggregates and filler aggregates for use in concrete.

Dr Leemann said the theory that frost caused the damage to concrete blocks in Donegal was contradicted by the geographic distribution of affected homes, in terms of rainfall and frost, and the fact: all sides of the homes were affected; the pattern of crack distribution in walls (bottom to top); crack characteristics (perpendicular to surface); and 75% of inner leafs exhibit cracks (27% with cracks 1.0 to 2.5 mm).

Professor Paul Dunlop, a research director in geography and environmental sciences at Ulster University, Coleraine, co-organised the Science and Societal Impacts of Defective Concrete conference.

Professor Dunlop said there was a lot to learn in Ireland about how concrete was being impacted by different minerals.

He added: “The whole issue is completely heartbreaking for many people. As scientists, we have been highly motivated to try and get scientific research into this matter because, from what we have seen on the ground, particularly here in Donegal, it is a very evolving situation and it is not not simply a case that mica is causing concrete to crack apart.

“As research scientists, we have been trying very hard to bring a group of people together who have good strong expertise and international track records in researching concrete and have the credibility to tackle a large scale project.

“Geological Survey of Ireland (GSI) in the springtime had a research call under their defective concrete products, as part of a Multi Supplier Framework Agreement - Concrete Products Project,” said Professor Dunlop.

The GSI International Scientific Research Team will comprise: Professor Dunlop, Dr Leemann, Professor Josée Duchesne and Professor Benoit Fournier (Canada); Dr Kay Willie, Dr Maria Chrysochoou and James Mahoney (US); and Nick Scaglione (US).
Professor Dunlop added: “[We] will be working on the ground in Ireland soon, sampling concrete and trying to analyse what has been going on within the cracking mechanism.

“We have also been working with the National Standards Authority of Ireland (NSAI) Technical Committee TC63.

“We had negotiations with it last week to try and see what sort of work packages and what are the main things we need to get going so we can get answers fairly quickly. And the research we will be doing will be used to inform the 1S 465 protocol that has been used to test people’s homes.”