Pick a building type and floor area — get a build-cost range from published Irish €/m² rates, broken into elemental categories. Every figure traceable, updated as you type.
A sentence or two gives you an indicative range — a general guide, not an exact figure — split into elemental packages. Include the floor area in m² if you know it: with an area, Irish briefs are priced from published €/m² rates and the comparable awards become the cross-check. Without one, the range is anchored to real public awards in the market you choose — and where those awards span too wide a spread to be a budget, we say so instead of guessing.