Modular buildings & garden dwellings in Galway
Modular buildings, Class 3 garden offices (up to 30 m²) and Class 3A habitable garden dwellings (32 to 45 m²) across Co. Galway, including Galway city, Tuam, Ballinasloe, Loughrea. An insulated garden office is €18,000 to €32,000, and a turnkey 35 to 45 m² Class 3A dwelling is €65,000 to €135,000 including 13.5% VAT.
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- 32 to 45 m²Class 3A exempt garden dwelling band in Co. Galway
- 80%of Co. Galway households in detached (59%) or semi-D (21%) houses
- 98,654occupied households in Co. Galway (CSO Census 2022)
- 1,860annual heating degree days near Galway
What modular buildings cost in Galway
Our price guide by size and specification, including 13.5% VAT on supply and installation.
| Job | Typical cost | What moves the price |
|---|---|---|
| Insulated garden office or studio, 12 to 16 m² (Class 3) | €18,000 to €32,000 | Cladding, glazing, base and cable run from the house |
| Large garden room or gym, 20 to 30 m² (Class 3 max) | €28,000 to €55,000 | Up to the 30 m² non-habitable exemption limit; no plumbing or kitchen |
| Class 3A habitable garden dwelling, 32 to 37 m² (1-bed) | €65,000 to €105,000 | Kitchen, shower room, Building Regs insulation, base and service hook-ups |
| Class 3A maximum garden dwelling, 40 to 45 m² (1 to 2 bed) | €80,000 to €135,000 | Largest exempt rear-garden unit (45 m² total garden structures cap) |
| Standalone 2 to 3 bed modular home, 75 to 85 m² | €175,000 to €255,000 | Full planning permission, BCAR, foundations and site services |
| Factory shell only (weathertight exterior), per m² | €1,200 to €1,800 a m² | Excludes groundworks, internal plumbing/kitchen and service connections |
| Insulated & fitted garden room rate, per m² | €1,600 to €2,400 a m² | Includes 13.5% VAT when supplied and installed by the builder |
| Turnkey habitable modular home rate, per m² | €2,400 to €3,200 a m² | All-in with kitchen, bathroom, foundations and 13.5% VAT |
Class 3 and Class 3A rules with Galway City Council or Galway County Council
The 27 July 2026 planning exemptions (S.I. Nos. 338 and 340 of 2026) apply across all of Co. Galway:
- Class 3 non-habitable garden offices and rooms (up to 30 m²): exempt behind the front wall of the house, provided all garden structures total no more than 30 m², at least 25 m² of garden remains, and the room is not slept in.
- Class 3A habitable garden dwellings (32 to 45 m²): exempt in the rear garden when the homeowner lives in the main house, total garden structures do not exceed 45 m², the unit connects to the main house's services, is not sold separately or short-term let, and you submit 14 days prior written notification (with Eircode) to Galway City Council or Galway County Council before starting work.
- Section 5 declaration: if you want written confirmation from Galway City Council or Galway County Council that your build is exempt, you can apply for a Section 5 declaration (€80 council fee, 4-week statutory response window).
Gardens, house types and towns in Co. Galway
At the 2022 Census, Co. Galway had 98,654 households, with 59% in detached houses (11th highest of the 26 counties, against 41% nationally) and 21% in semi-detached houses (25% nationally). Together, 80% of homes in Galway are detached or semi-detached properties — the house types most likely to have the rear garden footprint and side access needed for a 30 m² Class 3 garden room or a 32 to 45 m² Class 3A modular dwelling.
Near Galway, a typical year records 1,860 heating degree days (19th coldest of the 26 county towns). For a year-round garden office or habitable Class 3A dwelling in Galway, specify insulated walls, roof and floor to Building Regulation U-values and A-rated double or triple glazing.
Main towns covered in Co. Galway (Census 2022 population): Galway city (85,910), Tuam (9,647), Ballinasloe (6,597), Loughrea (6,322), Oranmore (5,819), Athenry (4,603).
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Galway modular building questions
How much does a modular garden dwelling or office cost in Galway?
An insulated, fitted 12 to 16 m² garden office costs €18,000 to €32,000, a 20 to 30 m² garden room €28,000 to €55,000, and a turnkey 32 to 45 m² Class 3A habitable garden dwelling €65,000 to €135,000, all including 13.5% VAT.
Do I need planning permission for a 45 m² granny flat in Galway?
Under Class 3A (S.I. No. 340 of 2026, in force 27 July 2026), a 32 to 45 m² detached habitable dwelling in your rear garden is exempt from planning permission if you live in the main house, keep total garden structures within 45 m², connect to the main house's services, and give Galway City Council or Galway County Council 14 days prior written notice with your Eircode.
Do you cover all of Co. Galway?
Yes — including Galway city, Tuam, Ballinasloe, Loughrea, Oranmore and every rural townland in Co. Galway. Your enquiry goes to one vetted modular building supplier covering Galway.
Get a written turnkey price for your modular building
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