Pretty basic concept: don't make crumbly concrete.
From Global Construction Review, August 29:
An estimated 7,500 homes, concentrated in but not restricted to the northwestern county of Donegal, have been affected by the so-called “Mica Crisis”, in which homes built largely from the late 1990s and into the 2000s have too much of the mineral, muscovite mica, present in the aggregate of their concrete blocks, according to one theory.
Mica absorbs and stores water, which expands when it freezes, thus undermining the cohesion of the cement and weakening the block. Deterioration is progressive because each freeze-thaw cycle opens the block to more water ingress. Cracks appear in walls, deepen, and spread as the blocks give way, allowing more water ingress.
Another impurity in concrete blocks, pyrite, is causing similar problems in western counties like Mayo, Galway, and Clare.
A third impurity – pyrrhotite, an iron sulfide that oxidises on contact with water and oxygen, creating new compounds that expand – was put forward by researchers from Ulster University and elsewhere last year as an overlooked, contributing factor in the mica crisis.
It’s political now
There’s no easy fix. Each affected wall must be replaced. In some cases, the whole house must be demolished and rebuilt.
The problem became apparent in 2013, but it wasn’t until June 2020 that the Irish government introduced an assistance scheme, offering 90% compensation, with grants of €49,500 for external wall replacement, rising to an upper limit of €247,500 for complete demolition and rebuild....
....MUCH MORE
