Two different defects, two different parts of the country, one thing in common: the house looks fine at a viewing and the bill is enormous.
Mica (defective concrete blocks)
Blocks with too much mica or pyrrhotite crumble over years. Cracking starts at corners and around windows, then the render maps out the blocks underneath. The grant scheme covers five counties: Donegal, Mayo, Clare, Limerick and Sligo. Houses built roughly 1990 to 2015 are the ones to worry about, though the range keeps widening. Ask the seller whether the house was ever tested (core samples, IS 465 assessment) and whether a scheme application was made. A surveyor should say in writing whether they saw the pattern cracking. If the house is in one of the five counties and in those years, ask for a block test before you sign.
Pyrite
Pyrite in the hardcore under the floor slab swells when wet. Floors lift and crack, doors stick, skirting boards move. Mostly Dublin, Meath, Kildare and Offaly, in houses built about 1997 to 2013 with stone from a handful of quarries. The Pyrite Resolution Board ran the remediation scheme; many affected estates have been fixed and carry a certificate of remediation. Ask for it. A fixed house is fine. An unfixed one in a known estate is a negotiation about the cost.
What checks can and cannot tell you
No public register lists affected houses by address. What the record does give: the county scheme designation, the build year from the BER certificate, and planning history that sometimes shows remediation works. That is what the report flags, with the questions to put to the seller and the surveyor. The rest is a core sample.