Renovations/Extension Costs in Dublin

Hello,
We are in the early stages of a project to renovate and extend a bungalow in Dublin. We are aiming at a fairly high quality build/insulation and average finishes.

Has anyone recent experience of the costs for in:-
(A) New Build for ground floor extension
(B) New Build for attic conversion (possibly same as A?)
(C) full renovation for existing building

We intend using a builder as opposed to contracting individual tradesman. We hope to have an architect on board for the project - but we have a separate budget for this.

I'd really appreciate any feedback.

For a new build ground floor extension, allow about €1500 per square metre as an initial ball park. Prices can vary obviously depending on the Contractor and choice of material/finishes etc...say allow +/- 20%.

be prepared to allow for 10/20% contingency on top of any estimate for the unknown unknowns that arise during an existing house ext/upgrade