New pyrite standards could help homeowners to sell

The new system will look at any future pyrite expansion

New pyrite standards could help homeowners to sell

File photo. Picture: Laura Hutton/

A reclassification of pyrite-affected homes and buildings could be good news for those looking to sell.

Pyrite can be found in the sedimentary rock and is used to make crushed stone for back-fill.

By itself pyrite is not normally a problem, but when its combined it with moisture and oxygen it can swell and crack.

The National Standards Authority of Ireland (NSAI) has announced revised standards - which are used by engineers, geologists and other technical experts when assessing buildings affected by pyrite.

The new version is intended to make it easier to categorise pyrite-affected properties, including more than 12,000 homes.

The four building categories will give more clarity on the susceptibility of the problem.

Categories A, B, C, and D have been redefined so that references to 'red', 'amber' and 'green' types of pyrite have been removed.

The new categories will examine if there is negligible risk of causing pyritic damage to the building in the future (Category A), that it will only incur minor damage to the building in the future (Category B), or that it has already caused significant pyritic damage or progressive damage to the building (Category D).

An example of a pyrite-affected wall | File photo

The potential future damage of buildings assigned to Category B, which were previously 'amber', is deemed limited to "minor damage".

"Minor damage" is defined as damage that is easily treated using periodic repairs e.g. cracks easily filled.

This Irish standard was updated to reflect the on-site experiences and evidence gathered by technical experts who have been using it over the past four years.

The update also follows consultation with members of the public and input from NSAI's Reactive Pyrite Technical Committee.

Geraldine Larkin, NSAI chief executive, said: "As anyone who has been affected by pyrite will know, unfortunately pyrite is unpredictable.

"NSAI’s Reactive Pyrite Technical Committee revised this standard to further reduce the possibility of ambiguity in deciding and interpreting results, and give more clarity to the categorisation process".

The NSAI says it received over 200 comments during the public consultation period, including many submissions from homeowners.