Outbuildings, Summer Houses & Garages

Q: Do outbuildings and garages need Planning Permission or Building Regs approval?

Not always. Most outbuildings fall under Class E Permitted Development, provided they meet strict criteria (such as a maximum height of 2.5m if within 2m of a boundary). For Building Regulations, standalone buildings under 15m² are usually exempt, while those between 15m² and 30m² are exempt if placed at least 1m from a boundary or built from non-combustible materials. However, any electrical work must always comply with Part P regulations.

Year-round space, without altering your main home.

Tarj Construction delivers high-performance outbuildings, fully insulated garden offices, and secure brick garages. From laying reinforced concrete slabs to integrating Part P compliant electrical systems, we build permanent, weather-tight structures designed for year-round use and long-term property value.

Premium garden rooms, secure garages, and fully compliant outbuildings.

Adding a garden office, summer house, or garage is a highly effective way to expand your lifestyle without the disruption of a main-house extension. However, a durable outbuilding requires far more than a basic timber shed structure. It demands reinforced SuDS-compliant foundations, damp-proof membranes (DPM), and strict adherence to Permitted Development (Class E) boundary rules across your London or Essex property. Tarj Construction delivers engineered, highly insulated (Part L) detached spaces with safe, NICEIC-certified power, ensuring your new room stays warm in the depths of winter and stands the test of time.

Fully Insulated Garden Offices & Studios
Detached & Attached Brick Garages
Bespoke Summer Houses & Leisure Rooms

Heavy-Duty Workshops & Home Gyms
Permitted Development (Class E) Projects

Complete Outbuilding Construction

From site preparation to finished standalone space.

Site Preparation & Foundations

A reliable outbuilding starts with proper groundwork, supported by our construction risk management to navigate boundary proximity and planning rules across London and Essex.

Site assessment, Permitted Development (Class E) and Planning Permission review
Ground levelling, excavation and root protection area (RPA) management
Concrete slab, raft or reinforced trench foundation installation
SuDS-compliant drainage planning and soakaway integration
Sub-base formation and trenching for underground services (SWA cables)

Structural Build

The structure is designed around durability and intended use, monitored closely through our quality assurance & site oversight.

Treated timber frame, blockwork cavity or mixed construction options
Framing, structural support and wind-bracing works
Steel reinforcement and heavy-duty lintels for garage openings
Damp proof course (DPC) and damp proof membrane (DPM) integration
Pitched or flat roof structure installation

Roofing & External Finishes

Weatherproofing and external detailing protect the building while complying with critical boundary height restrictions.

EPDM, GRP fibreglass or pitched roofing systems (adhering to strict 2.5m height limits where applicable)
Fire-rated external cladding or masonry for builds within 1m of a boundary
Secure, energy-efficient windows and external door installation
Automated garage doors or secure access systems
Guttering and rainwater drainage connections

Internal Fit-Out & Services

Optional upgrades turn a basic outbuilding into a fully habitable garden office, studio or workshop.

Part P compliant (NICEIC) electrical wiring, consumer units and lighting
Data cabling and internet connectivity for garden offices
Part L standard thermal insulation (PIR/mineral wool) for year-round use
Electric heating provision or climate control integration
Internal plasterboarding, skimming and durable flooring finishes

Compliance & Quality Control

Ensuring the build meets legal standards based on its floor area and use class, secured by our project governance & documentation.

Guidance on Building Regulations thresholds (15m² and 30m² exemptions), supported by our building safety audits
CDM 2015 health and safety control during construction
Final quality inspections and snagging resolution
Electrical installation certificates (Part P) compilation
Formal handover and completion documentation

Why Professionally Built Outbuildings Matter

Useful space, better durability and stronger long-term value.

Year-Round Practical Space

Create bespoke room for vehicles, home gyms, or workshops without the disruption of a house extension. We ensure your build safely complies with Permitted Development (Class E) boundary and height limits through early construction risk management.

Premium Garden Offices & Studios

Garden rooms must adapt to modern working needs. We deliver fully insulated, Part L compliant spaces with reliable NICEIC electrical and data integrations, elevating them far beyond standard, unheated timber summerhouses.

Legally Compliant Property Value

A permanent, well-designed garage or outbuilding increases market appeal. By securing your Part P electrical certificates and formalising any Building Control exemptions through our project governance, we ensure the added value is legally recognised when you sell or remortgage.

Engineered for Longevity

Proper reinforced slab foundations, damp-proof membranes (DPM), and SuDS-compliant drainage prevent the damp, subsidence, and rot that plague cheaper timber builds, monitored closely via our quality assurance oversight.

Engineered from the ground up.

How we deliver premium outbuildings and garages.

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

01. Site Appraisal & Feasibility

Assessing ground conditions across your London or Essex property, tree root protection areas (RPAs), and confirming your Class E Permitted Development boundary limits.

02. Groundworks & Foundation

Excavating and pouring a reinforced concrete slab or raft, integrating a heavy-duty damp-proof membrane (DPM) to guarantee a dry footprint.

03. Structural Build & Weatherproofing

Erecting the core structure (insulated timber frame or masonry), installing EPDM/GRP flat roofs (staying within the strict 2.5m boundary height limit), and fitting secure glazing.

04. Internal Fit-Out & Services

Trenching SWA armoured cables for safe power, followed by Part L compliant thermal insulation and Part P (NICEIC) certified electrical/data installations.

05. Final Inspection & Handover

Executing a final builders' clean, completing rigorous quality checks, and handing over your final electrical certificates and structural guarantees.

Planning a standalone building for your property?

Create new space that is practical, secure, durable, well-finished.

Speak with our construction team about your outbuilding, garage or summer house project. We’ll help you plan the right structure and deliver a build designed for long-term use.

Plan Your Project →

Frequently asked questions

Not always. Most outbuildings fall under Class E Permitted Development, provided they meet strict criteria (such as a maximum height of 2.5m if within 2m of a boundary). For Building Regulations, standalone buildings under 15m² are usually exempt, while those between 15m² and 30m² are exempt if placed at least 1m from a boundary or built from non-combustible materials. However, any electrical work must always comply with Part P regulations.

Absolutely. We do not build basic 'posh sheds'; we construct highly insulated, permanent garden buildings. We trench SWA (Steel Wire Armoured) cables from your main house to provide safe, NICEIC-certified electricity and reliable data connections, creating a professional workspace you can use comfortably 365 days a year.

A proper foundation is the difference between a building that lasts a lifetime and one that rots in five years. Depending on your ground conditions and tree root protection areas (RPAs), we typically excavate and pour a reinforced concrete slab or insulated raft foundation. Crucially, we always integrate a heavy-duty Damp Proof Membrane (DPM) to block rising moisture.

Yes. If you are building a brick garage, we can source matching bricks and roof tiles to ensure it looks like an original part of the property. For garden offices and summer houses, we offer a range of premium external finishes, including modern cedar cladding, render, and high-performance aluminium or UPVC bi-fold doors.

Yes. Unlike standard single-skin summer houses, we construct our premium outbuildings using Part L compliant thermal insulation (such as rigid PIR board). Combined with high-quality double glazing and optional climate control, your new London or Essex garden room will remain warm, dry, and energy-efficient throughout the British winter.