Self-Build vs Renovating in Ireland — When a Deep Retrofit Beats a Knock-Down Rebuild
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Retrofit of a 1970s bungalow: €310k, 6–12 months. Knock-down rebuild: €600k–€1m, 24–30 months. Trade-off is the existing structure.
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.
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.
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.
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.
Where to go next
Next decision
The next step in your build sequence.
- Budgeting a Self-Build in Ireland 2026 — The 5 Numbers Every Self-Builder Must Know →
- Self-Build Budget in Ireland 2026 — What €600k–€1m Actually Buys You →
- Self-Build First Steps in Ireland — The Seven Decisions to Make Before You Instruct Anyone →
- Self-Build Insurance and Warranty in Ireland — Site Cover, Structural Warranty, and Latent Defects →
Branch into
Adjacent decisions at the same stage.
- How Long Does a Self-Build Take in Ireland? The 18–36 Month Timeline, Stage by Stage →
- Self-Build Mortgages in Ireland — How Stage Drawdowns Work, Who Lends, and What You Need to Show →
- Self-Build Team in Ireland 2026 — Who You Need, When to Hire, and the Cost →
- Self-Build Timeline in Ireland 2026 — Month-by-Month, What Happens and When →
- When to Appoint an Architect in Ireland — Before Site Purchase, Not After Planning →
Watch out for
Common mistakes, hidden costs, gotchas.
Compare with
Alternative approaches worth knowing.