Self-Build vs Renovating in Ireland — When a Deep Retrofit Beats a Knock-Down Rebuild
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A deep retrofit of a 1970s bungalow in Ireland in 2026 runs €310k and takes 6–12 months on site. A knock-down rebuild on the same site runs €600k–€1m and takes 24–30 months. Retrofit wins on speed and cost. Knock-down wins on energy (BER A1 by design), layout (full control), and lifetime carbon (no demolition waste). The deciding question is the existing structure: are the walls, roof, and floor sound? An engineer inspection costs €500–€1,500 and tells you. If the structure is good, retrofit typically returns 70–90% of the BER and layout benefits at 40% of the cost. SEAI's Deep Retrofit scheme (2024) supports fabric upgrades on existing dwellings. Most Irish self-builders who chose retrofit in 2024 cite speed and cost; most who chose rebuild cite layout control and energy certainty.
TL;DR
Deep retrofit of a 1970s bungalow in Ireland: €310k, 6–12 months on site, BER upgrade from E2 to A1 typical.
Knock-down rebuild on the same site: €600k–€1m, 24–30 months, BER A1 by design, full layout control.
Retrofit wins on speed and cost if the existing structure is sound and the layout roughly works. Knock-down wins on energy, layout, and lifetime carbon if the existing fabric is poor.
When this matters most
You own a site with an existing structure and are weighing retrofit against rebuild.
When this doesn't apply
You're building on a greenfield site or a site with no existing structure.
Frequently asked questions
Is it cheaper to renovate or rebuild in Ireland?
Deep retrofit of a 1970s bungalow: €310k. Knock-down rebuild: €600k–€1m. Retrofit is typically 30–50% of rebuild cost if the existing structure is sound.
How long does a deep retrofit take?
6–12 months on site for a 150 m² 1970s bungalow. Faster than a self-build (9–15 months on site) because no foundation or structural work in most cases.
Can I get a BER A1 on a retrofit?
Yes, with external insulation, new windows, an airtightness layer, MVHR, and a heat pump. SEAI's Deep Retrofit scheme supports fabric upgrades. Expect €310k+ on a 1970s bungalow.
Sources
SEAI, Deep Retrofit Cost Benchmarks 2024. https://www.seai.ie/
SCSI (Society of Chartered Surveyors Ireland), Tender Price Index Q1 2026. https://www.scsi.ie/
Frequently asked questions
Is it cheaper to renovate or rebuild in Ireland?
Deep retrofit of a 1970s bungalow: €310k. Knock-down rebuild: €600k–€1m. Retrofit is typically 30–50% of rebuild cost if the existing structure is sound.
How long does a deep retrofit take?
6–12 months on site for a 150 m² 1970s bungalow. Faster than a self-build (9–15 months on site) because no foundation or structural work in most cases.
Can I get a BER A1 on a retrofit?
Yes, with external insulation, new windows, an airtightness layer, MVHR, and a heat pump. SEAI's Deep Retrofit scheme supports fabric upgrades. Expect €310k+ on a 1970s bungalow.