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House Extensions

Expand your home without the cost of moving.

Tarj Construction delivers high-performance house extensions designed to maximise your living space, lifestyle, and property value. From complex wrap-around kitchen extensions to double-storey additions, we manage the entire build with precision structural engineering, strict UK Building Regulations compliance, and seamless integration with your existing home.

Architectural integration and structural precision.

Extending a home requires far more than simply adding floor area. It demands safe load-bearing structural alterations, complex steelwork (RSJs), and meticulous roofline integration to ensure the new space performs perfectly. Tarj Construction delivers extensions across London and Essex through a strictly managed approach. We coordinate everything from deep foundation trenches to Part L compliant thermal upgrades, ensuring your new living space is structurally sound, legally certified by Local Authority Building Control (LABC), and feels like a natural continuation of the original building.

  • Rear & Open-Plan Kitchen Extensions
  • Side Return Extensions
  • Double-Storey Additions
  • Wrap-Around Extensions
  • Permitted Development & Planning Projects

Complete Extension Construction

From structural planning to
completed extension works.

Planning & Structural Preparation

Planning & Structural Preparation

Successful extensions begin with careful preparation, technical review and proactive construction risk management to prevent delays and budget overruns across your London or Essex property.

  • Site assessment, Permitted Development and Planning Permission review
  • Structural planning with engineers
  • Building Regulations (Part A-S) compliance preparation
  • Guidance on the Party Wall etc. Act 1996 and neighbourly matters
  • Coordination of Thames Water / local water authority build-over agreements
  • Construction programme preparation
Foundations & Structural Integration

Foundations & Structural Integration

New extension works must connect safely and reliably to the existing structure, monitored closely through our quality assurance & site oversight services.

  • Excavation, foundation works and Building Control trench inspections
  • Steel beam installation (RSJs/Universal Beams)
  • Load-bearing wall alterations and propping
  • Structural openings and reinforcements
  • Roofline and structural junction integration
External Construction

External Construction

External works must protect the building while helping the extension feel consistent with the original property.

Interior Construction & Finishing Works

Interior Construction & Finishing Works

Internal works are completed to create a practical, cohesive and handover-ready new space.

Compliance & Handover

Compliance & Handover

Final checks and rigorous project governance & documentation help ensure the extension is safe, compliant and ready for use.

Why Build an Extension

Creating more space while improving how your home works.

Increased Living Space (Improve, Don't Move)
01

Increased Living Space (Improve, Don't Move)

Extensions create vital room for open-plan kitchens, dining areas, or flexible family zones, allowing you to upgrade your lifestyle while avoiding the high costs of UK Stamp Duty, legal fees, and moving disruptions.
Protected Property Value
02

Protected Property Value

A properly constructed extension significantly boosts market appeal. Through our project governance, we secure the vital Local Authority Building Control (LABC) Completion Certificates needed to formalise that added value when you eventually sell or remortgage.
Improved Layout & Functionality
03

Improved Layout & Functionality

Open up outdated, fragmented layouts to create spaces that suit modern family life. We safely manage complex structural alterations (RSJs and load-bearing removals), supported by our quality assurance oversight, to seamlessly blend old and new.
Better Thermal Performance
04

Better Thermal Performance

Modern construction methods and Part L compliant insulation upgrades improve year-round comfort. Careful structural detailing eliminates thermal bridging, helping to reduce energy bills and improve your home's overall EPC rating.

Clear steps. Controlled delivery.

How house extensions are delivered.

We keep compliance practical: clear stages, documented evidence, and a trail you can rely on for governance and audit.
Compliance process illustration

01. Initial Consultation & Feasibility

Assessing your London or Essex property's potential, discussing Permitted Development (PD) rights, and outlining realistic budgets.

02. Structural & Regulatory Planning

Coordinating architectural drawings, structural engineer calculations, and Party Wall Act agreements.

03. Pre-Construction & Site Setup

Establishing strict logistics to protect your occupied home, minimising dust, noise, and disruption to your daily family life.

04. Foundations & Structural Knock-Throughs

Managing LABC trench inspections, installing structural steelwork (RSJs), and safely opening up the existing house.

06. Final Inspection & Handover

Executing a spotless builders' handover clean, completing rigorous snagging, and securing your vital Local Authority Building Control (LABC) Completion Certificate.

Thinking about extending your home?

Expand your space beautifully, safely, seamlessly, intelligently.

Speak with our construction team about your extension project. From early structural planning through to construction and final handover, we deliver carefully managed extension works built to integrate properly with your home.

Frequently asked questions

Not always. Many single-storey rear and side extensions fall under Permitted Development (PD) rights across London and Essex, meaning you don't need full planning permission. However, there are strict limits on height and footprint. We help you assess your PD rights and can guide you through the formal planning process if required.

If your extension involves digging foundations near a neighbour's property or altering a shared boundary wall, you must comply with the Party Wall etc. Act 1996. We provide early guidance on this process to ensure you serve the correct notices to your neighbours, preventing costly legal delays before the build begins.

In most cases, yes. We understand that moving out is expensive and disruptive. We set up strict dust barriers, temporary weatherproofing, and safe access routes. While there will be some unavoidable noise and dust during the 'knock-through' phase, we manage the site carefully and perform a final builders' handover clean to return your home to a pristine state.

We manage the entire Building Control process for you. Even if your extension doesn't need planning permission, it must comply with strict UK Building Regulations for structural safety, insulation (Part L), and fire safety. We coordinate all stage inspections with the Local Authority (LABC) or Approved Inspector to secure your final Completion Certificate.

Unexpected costs usually come from poor upfront planning or hidden ground conditions. We conduct thorough site assessments and apply rigorous construction risk management before digging starts. By establishing a fixed, transparent scope of works and actively managing our trades, we protect you from the unexpected variations common with unmanaged building projects.

A standard single-storey rear extension usually takes between 12 to 16 weeks, while a double-storey or complex wrap-around can take 16 to 24 weeks. We provide a clear construction programme on day one, ensuring materials are ordered in advance and our trades are scheduled seamlessly so your project doesn't sit idle.

LABC Warranty logo – UK building standards partner

CHAS Accredited Contractor logo – Health and safety compliance certification

National Federation of Builders logo – UK construction trade association

NICEIC Approved Contractor logo – Electrical safety certification

NICEIC Approved Contractor logo – Electrical safety certification

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