Design, Cost & Planning

House Extension Dublin — Full Cost Clarity Before Design Begins

Whether you need a single-storey rear extension, a two-storey extension, or a side extension, BuildTech manages the full process — feasibility, design, planning, and construction — with your budget as the starting point, not an afterthought.

We do not progress any project without a clear, agreed budget
If your expectations do not align with your budget, we will tell you immediately
Many extensions are planning exempt — we confirm your planning status at feasibility
Serving Greater Dublin — CIRI registered, fully insured, 100+ extensions delivered

Request a Consultation

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

Our team will respond within 1 business day.

NO OBLIGATIONCIRI REGISTERED
CIRI Registered
Construction Industry Register Ireland
CIF Member
Construction Industry Federation
5★ Google Rated
Verified by Dublin homeowners
100+ Projects Delivered
Across Greater Dublin Region
Feasibility First

Your Extension Budget, Confirmed Before Any Design Work Begins

The most common reason house extension projects fail in Dublin is that the design is produced before anyone has established what the build will actually cost. By the time contractors quote, the budget has already been exceeded — and the drawings are worthless.

BuildTech starts with a feasibility consultation. We establish what type of extension is achievable within your budget, whether planning permission is required, and what the full project will cost — before a single drawing is produced.

Feasibility consultation — €200 call or €500 home visit — confirms scope and full cost
Planning status confirmed — single-storey extensions up to 40m² are often exempt
Full cost plan provided before you commit to any design or construction fees
Request a Consultation →
House extension Dublin — BuildTech design and build project
Budget confirmed first Before any design work begins
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."

"BuildTech expertly handled my Dublin house renovation, offering professional, reliable service with clear communication, integrity, and cost-effective solutions, saving me time and stress. From the very first consultation I knew I was dealing with a team that genuinely cared about getting the job done right."

KW
Kirsten Wendenburg
Google

"Excellent communication and budget-friendly suggestions throughout."

"BuildTech fully renovated our house, offering excellent communication, budget-friendly suggestions, and efficient problem-solving. We are thrilled with the result, which exceeded our expectations. The team was professional at every stage and the final finish was outstanding."

OA
Olga Antipenko
Google

"Excellent communication and support throughout. Highly recommend."

"BuildTech helped with my rear extension, providing excellent communication and support throughout. The project was delivered on time and exactly as quoted. The team was respectful of our home and kept disruption to a minimum. Highly recommend to any Dublin homeowner."

JH
John Hagan
Google

"Handled my renovation with professionalism and care. Very pleased."

"BuildTech handled my renovation, including plumbing and plastering, with professionalism and care. Very pleased with the results. The team was courteous, tidy, and kept me informed at every stage."

JH
Jason Hollifield
Google

"Expertly guided my house renovation, delivering exactly what I wanted."

"BuildTech expertly guided my house renovation, delivering exactly what I wanted. The process was smooth from start to finish and the quality of the work speaks for itself."

SM
Salena McCarthy
Google

"Made building my home easy and successful."

"BuildTech made building my home easy and successful. The team was knowledgeable, responsive, and delivered on every promise. Thanks, BuildTech!"

JB
Judy Braodnax
Google

"My kitchen looks amazing after the renovation — great work from BuildTech!"

"My kitchen looks amazing after the renovation — great work from BuildTech! The team transformed the space completely and the quality of the finish is exceptional."

VV
Victoria Vetter
Google

"Kitchen and bathroom renovation — beautiful, eye-catching result."

"Thanks to BuildTech for my kitchen and bathroom renovation, giving my home a beautiful, eye-catching look. The team were professional throughout and the result exceeded what I had hoped for."

FP
Fabio Pulvirenti
Google

"The team was very kind to answer all my questions throughout."

"So far so good. The team was very kind to answer all my questions throughout the process and I felt informed and comfortable at every stage."

AH
Anne-Marie Hickey
Google

"Expertly managed my cottage renovation remotely — great communication and quality results."

"BuildTech expertly managed my cottage renovation remotely — great communication, quality results, and a helpful team. Highly recommended! The remote management process was seamless and the results were excellent."

KC
Kristen and Colm
Google

"Transformed our home with excellent management and clear communication."

"BuildTech transformed our home, providing excellent management and clear, responsive communication throughout the entire project. We are delighted with the result and would not hesitate to recommend them."

J
Justin
OT OnlineTradesmen

"Professional, courteous, punctual — stayed late, finished early. Excellent work."

"Ronan's team revamped a room, gutting, rewiring, insulating, plastering. Professional, courteous, punctual, stayed late, finished early, excellent work, very pleased. Would not hesitate to use BuildTech again."

D
Dylan
h Houzz

"Professional, courteous, punctual — finished early. Excellent work."

"Ronan's team revamped a room, gutting, rewiring, insulating, plastering. Professional, courteous, punctual, stayed late, finished early, excellent work, very pleased. A pleasure to deal with from start to finish."

M
Matt
h Houzz

"The client portal gives full project transparency — drawings, costs, updates and team comms."

"Buildtech's client portal gives full project access, drawings, costs, updates & team comms, ensuring full transparency. This level of visibility into the project is something I had never experienced with a contractor before — outstanding."

K
Kirsten
h Houzz

"Superbly renovated our home — great team, clear communication, outstanding results."

"BuildTech renovated our home superbly — great team, clear communication, smart advice, and outstanding results! Every aspect of the project was handled professionally and the quality of the finish is exceptional."

House extension construction Dublin — BuildTech project
Documentation prepared in-house No third-party delays
Design, Planning & Build

Every Stage Managed In-House — No Third-Party Delays

BuildTech manages the full house extension process in-house — from the measured survey and technical design through to planning, construction, and handover. Our in-house team eliminates the delays and miscommunications that occur when designers, planners, and builders are separate companies.

Every managed by a dedicated project manager, and certified by an independent chartered engineer on completion — giving you complete transparency and accountability throughout.

In-house architectural design, planning, structural coordination, and construction management
Certified on completion by an Independent Chartered Engineer — required for Building Control
Request a Consultation →

Not sure what your house extension will cost? We give you full cost clarity before you commit to anything.

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
Why BuildTech

Why Choose BuildTech for Your House Extension?

BuildTech is a specialist design and build contractor. House extensions are our core business — and we approach every project the same way: budget first, design second. We do not produce designs that cannot be built within your budget.

We are not a general builder. We are a specialist contractor with 100+ extension projects delivered across Greater Dublin, and a fixed-price guarantee on every project we take on.

We do not progress projects without a clear, agreed budget — always
Specialist contractor — not a general builder — 100+ extensions delivered in Dublin
In-house design, planning, and construction — full control of your project timeline
Certified by an Independent Chartered Engineer on completion
How It Works

Our Planning Application Process

BuildTech manages the full planning permission process from initial feasibility through to decision. Every stage is handled internally — there are no third-party handoffs that cause delays or miscommunication.

1

Feasibility & Exemption Check

We confirm whether your project requires planning permission or qualifies as Exempted Development. Many single-storey rear extensions in Dublin do not need planning — we establish this clearly at the outset, saving you time and fees.

2

Pre-Planning Strategy & Local Authority Engagement

Where planning is required, we develop a pre-planning strategy aligned with the relevant local authority's development policies. Where appropriate, we engage with the planning authority informally before submission to identify potential issues early and reduce the risk of refusal.

3

Planning Drawings & Documentation

Our in-house architectural design team prepares all required drawings — site location map, site plan, floor plans, elevations, and sections — along with any supporting reports and compliance documentation. Accurate, complete documentation reduces the risk of requests for further information from the council.

4

Submission & Application Management

We prepare and submit the full application to the relevant local authority — Dublin City Council, Dún Laoghaire-Rathdown, Fingal, or South Dublin County Council. We manage all correspondence and respond to any requests for further information within the statutory timeframes.

5

Decision Monitoring & Next Steps

We monitor the application through to decision — typically 8–12 weeks from submission. On receipt of planning permission, we advise on any conditions attached and prepare the project for the next stage: cost and technical design, or construction if design is already complete.

Common Issues

What Can Cause Delays or Refusals in Planning Applications?

Delays and refusals in planning applications are almost always avoidable with proper preparation. The most common causes in Dublin are:

Incomplete documentation

Missing drawings, incorrect scale, or absent site information trigger requests for further information — adding weeks to the process.

Policy conflicts

Designs that don't align with the local development plan — on height, scale, overlooking, or amenity — attract objections or conditions.

No pre-planning engagement

Submitting without checking with the planning authority first misses an opportunity to identify issues before they become formal refusal reasons.

Wrong application type

Applying for full permission when the works are Exempted Development — or vice versa — wastes time and money. We confirm the correct route at feasibility stage.

Exempted Development

What Can You Build Without Planning Permission in Dublin?

Many home extensions and improvements in Dublin qualify as Exempted Development under the Planning and Development Regulations — meaning no planning application is required. However, exemptions are subject to specific conditions and can be lost if previous unauthorised works exist on the property.

Common Exempted Development for residential properties includes:

Single-storey rear extensions up to 40m² (combined with any previous extensions) — provided the rear garden is not reduced below 25m²
Attic conversions using Velux-type rooflights that do not increase the ridge height or alter the front roofline
Domestic garages and sheds — subject to floor area and height limits
Solar PV panels and heat pump installations — subject to specific criteria

Not sure if your project needs planning?

BuildTech confirms planning status as part of every feasibility consultation — before any design fees are committed. If your project is Exempted Development, we will tell you clearly and save you the cost of an application.

Request a Feasibility Consultation →
Common Questions

Frequently Asked Questions

It depends on the type and size. Single-storey rear extensions up to 40m² combined are often Exempted Development — no planning required. Two-storey extensions, side extensions to the front building line, and any extension reducing the rear garden below 25m² will typically require planning. BuildTech confirms your planning status at the feasibility stage before any design fees are committed.
The typical range is €2,500 to €3,500 per m², depending on the complexity of the build and how much work is required to tie the extension into the existing house. A 25m² single-storey rear extension would typically cost €62,500–€87,500 all-in. A BuildTech feasibility assessment gives you an accurate, project-specific cost plan before any commitment.
A standard single-storey rear extension takes 12–20 weeks from construction start to completion. A two-storey extension typically takes 20–32 weeks. Where planning permission is required, allow an additional 8–12 weeks. BuildTech provides a full programme at the cost and technical design stage.
BuildTech's minimum project value is €100,000. We do not take on single-trade works, cosmetic renovations, or projects below this threshold. If your project is below this value, we will tell you clearly at the outset.
What We Do

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 ★ Core

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 Start Here

€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.

Learn more →

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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Take the First Step

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.

No obligation. No pressure. Just honest advice.

Call Us Get a Consultation