Can I buy a house with an unauthorised extension in Ireland?

Buying a property with an unauthorised extension is not prohibited, but it means taking on a property whose planning status is not fully regularised, which can affect its value, saleability, and exposure to future enforcement action. Enforcement liability generally attaches to the land and the current owner rather than automatically disappearing on sale, so a buyer can find themselves dealing with a council investigation or enforcement notice that originated before they owned the property.

During conveyancing, a solicitor will typically review the planning history, compare it against the physical structure, and flag any extension or alteration that appears to lack permission or exceed exempted development limits. Where an issue is identified, common outcomes include the seller obtaining retention permission before closing, a reduction in the purchase price to reflect the risk and cost of future retention, or the buyer proceeding with full awareness and a plan to apply for retention themselves after completion.

Mortgage lenders are generally cautious about unauthorised structures, and many will require retention permission to be in place, or a solicitor's certificate of exemption confirming the works fall within exempted development, before releasing funds, particularly where the extension adds significant floor area or value to the property. Cash buyers have more flexibility but still take on the underlying planning risk.