Attic Conversion in Galway: Roof Work and Costs Guide

Attic conversions are the most popular way to add space to a Galway home without building out into the garden. Across Salthill, Renmore, Knocknacarra and the newer estates in Oranmore and Athenry, homeowners are turning unused roof voids into bedrooms, home offices and playrooms. But the success of any attic conversion depends on one thing above all: the roof itself. This guide explains the roofing work involved, what it costs in 2026, and how to prepare your roof for the project.

Why the Roof Structure Matters Most

The first question a roofer asks is whether your roof can take a conversion at all. Galway housing stock splits into two types. Older houses from the 1930s to the 1960s, common in Salthill, Shantalla and Renmore, usually have traditional cut roofs with large internal rafters and purlins. These give you headroom and are often straightforward to convert.

Modern estate houses built from the 1990s onwards, like many in Oranmore, Athenry and Tuam, use pre-formed roof trusses. The criss-cross timber web of a trussed roof leaves almost no usable headroom, and you cannot simply cut the trusses out. A structural engineer must design a new support system, usually steel beams, and the roof structure is altered before any finishing work begins. This structural work is the single biggest variable in your overall cost.

Dormers, Roof Windows and the Roofing Work Involved

A roof window conversion adds Velux-style windows into the existing slope. This is the lighter option: the roofer cuts the opening, installs the window and re-flashes around it. On a typical semi-detached Galway house this is the most affordable way to create a bedroom or office.

A dormer conversion goes further. The roof slope is cut away, a dormer structure is built, and the surrounding roof is re-slated or re-tiled to tie into the new walls. Getting the flashings, valleys and junctions right is where a skilled roofer earns their keep, because this is where leaks start years later. If you have a slate roof, matching the existing slate keeps the roof looking original, and our slate roofing services cover dormer junctions and re-slating work.

What Does an Attic Conversion Cost in Galway?

Realistic 2026 figures for Irish attic conversions are EUR18,000 to EUR28,000 for a roof window conversion on a typical semi-detached house, and EUR25,000 to EUR60,000 for a dormer conversion, depending on size, finish and whether you add an en-suite. The roofing portion of that bill, covering structure, dormer, windows and re-roofing, typically runs from EUR8,000 to EUR20,000.

Your own figure depends on roof type, access and the condition of the existing roof. If the slates are old and the flashings are tired, it is false economy to convert under a roof that will need replacing in a few years. Our guide to new roof costs in Galway helps you compare repair, re-cover and full replacement before you commit.

Planning Permission and Building Regulations

Many attic conversions in Ireland do not need full planning permission, but the exemptions are tight. A dormer on the rear of the house is often exempt, while a dormer visible from the road usually needs permission, and there are strict volume limits. Check with Galway City Council or Galway County Council before you spend a euro on drawings.

Building regulations always apply. Fire escape windows, stair geometry, headroom, insulation and structural safety are all inspected. A reputable contractor manages the compliance paperwork, but the roof openings and structure must be signed off by a structural engineer.

Ventilation and Insulation: Do Not Skip These

A converted attic sits right under the roof, so the roof build-up matters more than anywhere else in the house. Insulation between and over the rafters, a proper vapour barrier and ventilation at the eaves and ridge keep the room warm and dry. Galway's damp Atlantic air punishes attics that are sealed up without airflow, and condensation and mould are the classic result. Read our guide to roof ventilation and condensation before you insulate.

Insulation and heating upgrades may also qualify for SEAI grants, which can shave thousands off the total, so it is worth checking your eligibility early in the project.

Prepare the Roof Before You Convert

Get a full roof survey before any structural work starts. Slates, flashings, chimney, ridge and gutters should all be sound, because fixing problems from inside a converted attic is far more expensive than fixing them before you begin. Replace damaged slates, repair flashings and sort any leaks first.

Finally, choose your roofer on experience with conversions, not just repairs. Ask for examples of dormer work in Galway, inspect the junctions and flashings up close, and get a written itemised quote.

Ready to talk through your attic conversion? Call 087 338 6136 for a free roof survey and a straight answer on what your Galway roof will need.