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Extensions / Conversions in Mitcham (289)

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    LMB Group Ltd Logo

    LMB Group Ltd

    8.84

    (178 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Loft Conversions
    Call
  • John and Collin Smith Builders

    9.95

    (128 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Suspended Ceilings
    Partition Walls
    Demolition
    Call
  • Jack's Builders Limited Logo

    Jack's Builders Limited

    10.00

    (3 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Loft Conversions
    Partition Walls
    Concrete Garages
    Call
  • Fine Point Construction LTD Logo

    Fine Point Construction LTD

    10.00

    (3 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Sustainable Construction
    Agricultural Building
    Workshop Design / Construction
    Call
  • Abaco Marea Logo

    Abaco Marea

    9.50

    (108 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Loft Conversions
    Refurbishments
    Sustainable Construction
    Call
  • DAVID STAN PROPERTIES LIMITED Logo

    DAVID STAN PROPERTIES LIMITED

    10.00

    (1 review)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Concreting
    Wall Tie Replacements
    Foundations
    Call
  • L & D Home Developments Ltd Logo

    L & D Home Developments Ltd

    9.89

    (127 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Concreting
    General Building
    Foundations
    Call
  • Prime Development Projects Ltd Logo

    Prime Development Projects Ltd

    10.00

    (1 review)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Concreting
    Period Property Restoration
    Foundations
    Call
  • Henry b builders limited Logo

    Henry b builders limited

    9.90

    (11 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Emergency Builder Service
    Wall Tie Replacements
    Steel Fabrication
    Call
  • Ascent Loft Conversions Ltd Logo

    Ascent Loft Conversions Ltd

    9.50

    (17 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Garden Studios
    Period Property Restoration
    Garage Conversions
    Call
  • Buildon Construction Ltd Logo

    Buildon Construction Ltd

    10.00

    (107 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Agricultural Building
    Cladding
    Fire and Flood Renovation
    Call
  • Edibuildingservice Logo

    Edibuildingservice

    9.93

    (92 reviews)

    Operates in Mitcham

    Services & skills
    Builder
    Extensions / Conversions
    Stretched Ceilings
    Heritage Property Specialist
    New Builds
    Call

Conversion and extension builders in Mitcham

Planning a loft conversion, garage makeover or full house extension in Mitcham? You’re in the right place. Whether you’re adding space for a growing family, upgrading your layout or increasing your home’s value, we can help you find the right tradesperson for the job.

Find extension and conversion builders in Mitcham

Every builder on Checkatrade passes up to 12 checks before they appear in your search. You can read verified reviews, compare services, and even post your job to get quotes straight to your inbox, all in a few clicks. That’s how we help homeowners like you get a job done right.

What to expect from hiring an extension or conversion builder in Mitcham

Our checked tradespeople in Mitcham cover a wide range of projects, including:

  • Single or double-storey house extensions

  • Kitchen and diner extensions

  • Loft, attic, garage or basement conversions

  • Garden room extensions

  • Utility room extensions

  • Over-garage extensions and side returns

Costs to expect

Costs of extensions and conversions vary depending on size, structure and spec, but here's a rough guide:

Single - storey extensions: £21,000 - £65,000

Double - storey extensions: £55,000 - £95,000

Loft conversions: £35,000 - £65,000

Garage conversions: £8,000 - £20,000

What to check before you hire:

  • Are drawings or planning permissions needed?
  • Are they familiar with building regs?
  • Is the quote fixed or flexible?
  • Does it cover materials and project management?

Most builders will include prep, construction, electrics, plumbing and final finishes in their quote, but always double-check. Timelines range from a few weeks for simple jobs to several months for bigger builds.

Extension and conversion builders in Mitcham: Homeowners vs renters

Homeowners:

You’re in charge of the project. That means hiring the builder, securing permissions, and paying for the work. You may need:

  • Planning permission (especially for double-storey builds or changes near boundaries)

  • Drawings from an architect or structural engineer

  • Building regs approval

If you’re not sure where to start, speak to a local builder or post your job to get help with the process.

Renters:

You’ll usually need your landlord’s approval to make any big changes. In most cases, your landlord will be the one arranging and paying for structural changes like loft conversions or extensions. That said, it’s worth flagging ideas if you think they’ll improve the property, especially if it means longer tenancies or fewer repairs.

Emergency extension or conversion help in Mitcham

Extensions and conversions are big projects, but sometimes, things go wrong and need sorting fast. Common urgent issues include:

  • Leaks in newly converted lofts

  • Structural cracks or shifting

  • Faulty electrics or plumbing in newly added rooms

  • Incomplete work by previous builders

Facing an emergency in Mitcham? Enter your postcode or post a job to find emergency services in your area.

Find the right extension or conversion specialist in Mitcham

Looking for a builder to help with:

  • Rear house extensions
  • Kitchen extensions
  • Garage conversions
  • Loft or attic conversions
  • Garden room builds
  • Basement or cellar conversions
  • Conservatory roof upgrades
  • Utility or porch extensions

Looking for more tradespeople in Mitcham?

Find Checkatrade reviewed Tradespeople, get a quote today, discover related services in Mitcham and check out our latest home improvement guides.