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Design, Cost & Planning

House Extensions in Dublin, Built Around Your Budget From Day One

Know what your extension will cost, and whether it needs planning permission, before you spend a euro on drawings. We deliver single-storey rear, two-storey and side extensions across Dublin, from the first feasibility check through to a certified handover.

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0818 333 443
  • No design fees until your budget and scope are agreed
  • If your budget and your plans do not match, we say so at the first call, not after you have paid for drawings
  • Rear extensions up to 40m² are often planning exempt, and we confirm yours at feasibility
  • Greater Dublin, CIRI registered and fully insured, 100+ extensions delivered

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All enquiries are reviewed by our team before a consultation is confirmed.

CIRI Registered

Construction Industry Register Ireland

5★ Google Rated

Verified by Dublin homeowners

CIF Member

Construction Industry Federation

100+ Projects Delivered

Across Greater Dublin Region

We Price Your House Extension Before We Draw It

Most Dublin house extension budgets come undone in the same order. You pay for a full set of drawings, you commit to them, then the builder’s quote lands well above what you can spend. 

We start with a feasibility consultation instead. A €200 call or a €500 home visit establishes what your budget will actually build, whether planning permission applies, and a realistic scope, all before any design work begins. Every design decision then follows a figure you have already agreed, so nothing you pay for turns out to be unbuildable.

  • €200 feasibility call or €500 home visit, both confirm your scope, planning route and realistic cost
  • Planning status checked upfront, since single-storey rear extensions up to 40m² are often exempt
  • A clear cost plan before you commit to any design or construction fee
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Client Reviews

What Our Clients Say

Rated 5★ across Google, Houzz, and OnlineTradesmen by Dublin homeowners.

★ ★ ★ ★ ★
GB
Graham Barry
Google

"Professional, reliable service with clear communication and integrity."

"Professional, reliable service with clear communication and integrity. The team kept us informed at every stage and delivered exactly what was promised. Would recommend to anyone looking for a trustworthy provider."

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★ ★ ★ ★ ★
KW
Kirsten Wendenburg
Google

"Excellent communication and budget-friendly suggestions throughout."

"Excellent communication and budget-friendly suggestions throughout. They took the time to understand our needs and offered practical options at every step. The end result exceeded our expectations."

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★ ★ ★ ★ ★
OA
Olga Antipenko
Google

"Excellent communication and support throughout. Highly recommend."

"Excellent communication and support throughout. Highly recommend. From the first call to the final handover everything was handled professionally. The team was responsive, knowledgeable and clearly cared about the outcome."

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★ ★ ★ ★ ★
JM
James Murphy
Google

"Outstanding work from start to finish. Couldn't be happier with the result."

"Outstanding work from start to finish. Couldn't be happier with the result. They were punctual, tidy and clearly took pride in their craft. The whole project came in on time and on budget."

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★ ★ ★ ★ ★
SO
Sarah O'Brien
Google

"Genuinely impressed with the quality and attention to detail."

"Genuinely impressed with the quality and attention to detail. Every aspect of the project was carefully considered and the finish is excellent. I'd use them again without hesitation."

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★ ★ ★ ★ ★
DK
David Kelly
Google

"Top-class service. Friendly team and a fair price."

"Top-class service. Friendly team and a fair price. They were upfront about everything, no hidden surprises and the work was completed to a very high standard. Already recommended them to a neighbour."

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One Accountable Team, From First Survey to Final Sign-Off

When your designer, planner and builder are three separate firms, the gaps between them quietly become your problem: details lost in handover, blame passed around, and a timeline that slips every time the baton is dropped.

BuildTech keeps the measured survey, technical design, planning, construction, and structural engineering inside one team. You get one point of contact and one dedicated project manager, and every completed extension is signed off by an independent chartered engineer, which Building Control requires.

  • Survey, design, planning, structural and build, all under one roof
  • Independent chartered engineer certification on completion, as required for Building Control
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Not sure what your home renovation will cost? We give you full cost clarity before you commit to anything.

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0818 333 443
How It Works

A Structured Process Built Around Your Budget

BuildTech follows a clear four-step pathway, from initial feasibility through to completed construction, designed to protect your budget and keep your project on track.

1

Feasibility

Budget & scope clarity before any design work begins

Design

Measured survey, technical layout & cost plan
2
3

Planning

Managed application where required, many extensions are exempt

Build

On-time, on-budget delivery with full project management
4
Start with a Feasibility Call
Why BuildTech

Why Homeowners Pick BuildTech for Dublin House Extension

We are specialist extension builders in Dublin, and a full design and build contractor under one roof. House extensions and renovations are our whole business, not a sideline. That focus is why our projects stay on budget and on programme.

Every project runs to a fixed price, agreed before work starts. If your budget will not build what you have in mind, we say so at the first call. We would rather turn the job down than take on one that cannot be built for the money.

  • Budget first, always. No design, and no build, without a cost you have approved
  • Extension specialists. 100+ house extensions delivered across Greater Dublin
  • One in-house team. Design, planning and construction together, so your timeline stays ours to protect
  • Certified on completion. Independent chartered engineer sign-off, as Building Control requires

How We Handle Your Planning Application, End to End

We run the whole application in-house if your extension needs permission.

Exemption Check First

Before anything else, we confirm whether your extension needs permission at all. Many single-storey rear extensions in Dublin are exempt, and establishing that early saves you weeks and unnecessary fees.

Pre-Planning Strategy

Where permission is required, we shape the design around your local authority’s development plan. Our planning permission experts raise it informally with the planners before submission to surface issues early.

Drawings and Documentation

Our in-house team prepares the full set: site location map, site plan, floor plans, elevations, sections and any supporting reports. Complete, accurate documents are the best defence against a request for further information.

Submission and Management

We lodge the application with the relevant council, whether that is Dublin City, Dún Laoghaire-Rathdown, Fingal or South Dublin. We also manage every piece of correspondence within the statutory timelines.

Decision and Next Steps

We track the application to decision, usually 8 to 12 weeks. Later, we talk you through any conditions and move the project into technical design or construction.

Common Issues

Things That Slow Down House Extension Planning Application

Refusals and delays are nearly always preventable. In Dublin, four causes come up again and again.

Missing or wrong drawings

Absent site information, incorrect scale or an incomplete set triggers a request for further information and adds weeks to the clock.

Conflict with the development plan

Designs that ignore local rules on height, scale, overlooking or amenity attract objections and conditions, or an outright refusal.

Skipping pre-planning

Lodging without checking with the planners first throws away the chance to fix problems before they become formal reasons for refusal.

The wrong application entirely

Applying for full permission on work that is exempt, or the reverse, burns time and money. We settle the correct route at feasibility.

What You Can Build in Dublin Without Planning Permission

A lot of extension work in Dublin qualifies as Exempted Development under the Planning and Development Regulations, which means no application is needed. The catch is that the exemption comes with conditions, and it can be lost where unauthorised work already exists on the property.

For most homes, the common exemptions include:

  • Single-storey rear extensions up to 40m², counting any previous extensions, provided at least 25m² of private open space remains to the rear
  • The extension staying within the height of the existing house
  • Boundary and overlooking conditions being met
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Common Questions

Frequently Asked Questions

Often, no. A single-storey rear extension is generally exempt up to 40m² combined with any previous extensions, as long as at least 25m² of private open space stays to the rear. Two-storey extensions, anything forward of the building line, and any build that eats into that garden space usually need permission. We confirm your position at feasibility, before any design fee.
Cost swings widely with the type of extension, the roof, ground conditions, the finish, and VAT at 13.5% on top. Rather than give you a number that will not hold, we establish your real cost at the feasibility stage and put it in writing as a scoped, fixed price before any design work begins.
A straightforward single-storey rear extension usually runs 12 to 20 weeks on site. A two-storey extension typically takes 20 to 32 weeks. Where planning permission is needed, add roughly 8 to 12 weeks before the build starts. You get a full programme at the cost and technical design stage, not a best-case guess.
Our minimum project value is €100,000. We do not take on single-trade jobs, cosmetic refreshes or anything below that figure. If your project sits under the threshold, we will tell you plainly at the first call rather than waste your time.
Yes. BuildTech is a design and build contractor, so one in-house team takes your extension from survey and drawings through planning and onto site. We arrange a dedicated and accountable team throughout the process..

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We review your enquiry before confirming a consultation — ensuring only suitable projects proceed.

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  • Min. project €100k · No surprises

What's Included

  • Feasibility consultation included
  • Measured survey & assessment
  • Technical design package
  • Full project management
  • Engineer certification on completion

Related Services

Home Renovation

House Extension

Attic Conversion

Deep Retrofit

Feasibility Consultation

Not sure where to start?

A feasibility consultation (€200 call · €500 home visit) confirms your planning position before you spend anything on drawings.

Book Feasibility Call
Explore more

Our Services

BuildTech is a specialist design and build contractor. We take on a focused range of projects — and we do not progress any project without a clear, agreed budget.

Single-Storey Rear Extension

The most common home project in Dublin. Open-plan kitchen and living, utility room, or additional family space — from feasibility through to a certified, compliant build.

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Home Renovation

Whole-home renovations and structural alterations for Dublin homeowners. Internal reconfigurations, layout redesign, and full refurbishment — all budget-led from day one.

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Feasibility Consultation

€200 call or €500 home visit. We establish what is realistically achievable within your budget before any design work begins — saving you time, money, and stress.

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Planning Permission

Full application management — pre-planning strategy, drawings, submission, and decision monitoring. Many extensions are planning exempt; we confirm this first.

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Already Have Plans?

Cost Planning & Construction Review from €2,500 + VAT. We provide a full cost breakdown of your existing drawings — gap identification, budget alignment, and value engineering.

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Cost & Technical Design

Measured survey, technical layout, and a detailed cost plan — all aligned to your budget before construction begins. No over-specified designs that cannot be built within your means.

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Our work

Recent Projects

Each project below started with a feasibility consultation and a clear budget. Here is what we delivered.

All Projects

Extension + Renovation

Full Ground Floor Renovation with Rear Extension

Location : Dublin

Scope : Ground floor knock-through, rear extension, open-plan kitchen and living

Status : Planning exempt

✓ Delivered on time and on budget

Extension + Renovation

Sandymount Seafront
Renovation

Location : Sandymount, Dublin 4

Scope : Full home renovation of period seafront property

Status : Planning exempt

✓ Full project management, completed on programme

Extension + Renovation

Rear Extension Plus Partial Renovation, Dublin 14

Location : Dublin 14

Scope : Single-storey rear extension and partial ground-floor renovation

Status : Planning exempt

✓ On budget, handover on schedule

Extension + Renovation

20 sqm Single-Storey Rear Extension, Mount Merrion

Location : Mount Merrion, South Dublin

Scope : 20 sqm flat-roof rear extension, open-plan kitchen and dining

Status : Planning exempt

✓ Completed on time and on budget

Extension + Renovation

Split-Level Open Plan Kitchen & Lounge Renovation

Location : Dublin

Scope : Structural reconfiguration, split-level open-plan kitchen and lounge

Status : Planning exempt

✓ Full project management included

Ready to Build Your House Extension?

A BuildTech feasibility consultation gives you full cost clarity — before you commit to any design or construction fees. We do not progress projects without a clear, agreed budget.

Request a Consultation →
0818 333 443

No obligation. No pressure. Just honest advice.