The Proline Medium from 3.46m x 3.46m

From £20,278

The Proline garden room offers a seamless indoor-outdoor experience with timber-framed doors and windows. Fully insulated and finished with low-maintenance Tricoya cladding, it delivers a sleek, modern look that can be factory painted in any RAL colour. Customise the design by moving or changing the doors and windows to suit your style. A classic, high-end member of our garden offices range.

Standard Features

  • Insulation in walls, roof & floor
  • Factory painted doors & windows
  • Factory painted exterior walls
  • V-Grooved MDF painted internal lining
  • Tongue & groove timber floor
  • Garden Affairs assembly
  • Delivery to the UK via articulated lorry - delivery charges for a smaller vehicle will apply where access is restricted
  • Timber Deckbase£2,095.03
    Concrete Base£2,394.32
    Interior Factory Painting Estimate£2,300.00
    Laminate Flooring Upgrade£1,257.02
    Standard Electrical Package *£1,200.00
    Sedum Living Roof£1,676.02
    Timber Deckbase£2,428.06
    Concrete Base£2,774.92
    Interior Factory Painting Estimate£2,300.00
    Laminate Flooring Upgrade£1,456.83
    Standard Electrical Package *£1,200.00
    Sedum Living Roof£1,942.44

    * excluding connection to the house

    Total Cost
    Building Cost
    £
    Assembly Cost
    £
  • The following table displays the available sizes for this product. For a bespoke project, please get in touch.

    WxD3.46 m4.01 m
    3.46m11.97m213.87m2

    What could influence your price?

    This building is fully customisable and made-to-order. Changes to the design such as the ones listed opposite can have an affect on the overall price.

    • Size
    • Window and door configuration
    • Factory paint finish
    • Selection of optional extras

Examples of Proline garden building designs

Our flat roof Proline is fully customisable, below are some examples of alternate designs.

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 2.36m x 3.46m

Proline Medium - 2.36m x 3.46m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 2.91m x 2.91m

Proline Medium - 2.91m x 2.91m

Proline Medium - 3.46m x 2.36m

Proline Medium - 3.46m x 2.36m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.56m x 2.91m

Proline Medium - 4.56m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 3.46m

Proline Medium - 4.01m x 3.46m

Proline Medium - 2.36m x 3.46m

Proline Medium - 2.36m x 3.46m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

Proline Medium - 4.01m x 2.91m

  • Details & Specifications

    Rot-free, low-maintenance exterior

    The stylish, paint-finished, vertical tongue and groove effect exterior cladding is produced from Tricoya, an exceptionally stable modern wood composite with a 50-year life above ground. It handles all outdoor weather conditions and moisture variations effortlessly, being resistant to rot, warping, and fungal attacks.

    The Proline features a professional factory-applied paint finish that is eco-friendly, water-based, and high-quality. Available in any RAL colour as standard, this allows you to personalize your building to match your garden's aesthetic.

    Modular sizes

    Choose from a comprehensive range of modular sizes. Buildings range from 1.8m to 5.6m in width and up to 3.4m in depth, making them suitable for any garden size. You can add the doors and windows of your choice to design a building that suits your style.

    Fully insulated

    The Proline is fully insulated in the roof, floor, and walls, providing comfort throughout the year. This ensures a breathable building with a stable temperature, so you can enjoy your workspace, relaxation area, or hobby room regardless of the British weather.

  • All Features

    Low-Maintenance Cladding

    The stylish, paint-coated vertical tongue & groove cladding on the exterior is constructed from Tricoya, a high-end wood composite.

    Fully Insulated

    With insulation integrated into the roof, floor, and walls, the Proline offers a comfortable environment for work or play all year long.

    2.5m High Flat Roof

    Designed to be 2.5m tall, the Proline typically falls within permitted development rights. Its EPDM rubber roof has a 2-3 degree slope for effective water run-off.

    Double Glazed Doors & Windows

    Featuring double glazing, our high-quality timber doors and windows provide security with multi-point locking systems.

    Factory Paint Finish

    Choose from a broad palette of colours for our factory-painted doors, windows, and exterior walls, all finished as standard.

    Internally Lined & Painted

    The luxury building boasts a v-grooved, painted MDF internal lining on the walls and ceiling, included as standard.

    Fully Customisable Design

    With Proline buildings, you can personalize the size, doors, windows, colour, and lining to craft the perfect building for you.

  • Custom Options

    Prolines are fully customisable to suit your garden.

    Below are the custom options available:

    Size

    Customise your building to the exact size to suit your requirements.

    Size

    Doors and Windows

    Choose from a wide range of timber-framed, double-glazed door and window options.

    Doors and Windows

    Flooring

    Upgrade the tongue and groove timber floor to a high-quality laminate floor which is available in two colours.

    Flooring

    Colours

    Choose to have your doors and windows painted in a wide range of colours.

    Colours

    Electrical Spec

    We offer first and second fix electrics with a selection of fitting available.

    Electrical Spec

    Canopies

    Add a custom-size canopy to shelter from rain and shine and create and indoor-outdoor flow.

    Canopies

    Internal Lining

    Choose to have your modular building finished with a high-spec painted MDF or a rustic timber lining.

    Internal Lining

  • Product Video

  • FAQs

    • How long will installation take?

      Depending on the size, most of our garden buildings can be installed in 1-4 days.

    • Can you supply a base?

      Yes. At Garden Affairs, we have taken away the hassle of finding tradespeople to install your garden room base. We offer both a deck & concrete base for buildings we are installing.

    • How do I order?

      Please call us to place your order. You can pay by credit or debit card, cheque or bank transfer. A 25% deposit is required with all orders. The final balance is payable on completion when installed by Garden Affairs, or 7 days prior to delivery for self-assembly customers.

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Let's design your ideal Proline building

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©2026 Titan Garden Buildings Limited trading as Garden Affairs
Registered in England & Wales at Titan Garden Buildings, Portsmouth Road, Ripley, Surrey, GU23 6EW
Company number: 05760433.

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Speak to an advisor? 01225 774566

Speak to an advisor?

01225 774566