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Extensions / Conversions in Mountain Ash (18)

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  • Keramics Logo

    Keramics

    10.00

    (49 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Cladding
    Partition Walls
    Concreting
    Call
  • Inavision Construction Logo

    Inavision Construction

    9.87

    (26 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Brick / Concrete Structural Repairs
    Property Maintenance / Repair
    Emergency Builder Service
    Call
  • Orange Stone Construction Logo

    Orange Stone Construction

    10.00

    (5 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Wall Tie Replacements
    Agricultural Building
    Warehouse Racking
    Call
  • ADS Carpentry and Building Services

    9.67

    (60 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Basement / Cellar Conversions
    Garden Studios
    Foundations
    Call
  • Carpo's Construction Ltd Logo

    Carpo's Construction Ltd

    9.75

    (4 reviews)

    Operates in Mountain Ash

    Suggested Services
    Extensions / Conversions
    Price on request
    Call
  • LMB Construction (SW) Limited Logo

    LMB Construction (SW) Limited

    (12 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    New Builds
    Suspended Ceilings
    Garage Conversions
    Call
  • GMSG Building Ltd Logo

    GMSG Building Ltd

    10.00

    (21 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Loft Conversions
    Emergency Builder Service
    Property Maintenance / Repair
    Call
  • MM Building and Construction working with MIKEL renovations Logo

    MM Building and Construction working with MIKEL renovations

    10.00

    (34 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Car Ports
    Fire and Flood Renovation
    Sustainable Construction
    Call
  • Tri Dyn Electrical and Building Services Logo

    Tri Dyn Electrical and Building Services

    9.87

    (16 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Brick / Concrete Structural Repairs
    Structural Design
    Steel Fabrication
    Call
  • Bluestone Construction & Landscapes Logo

    Bluestone Construction & Landscapes

    10.00

    (27 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Concreting
    Garden Studios
    Warehouse Racking
    Call
  • G W CARPENTRY AND BUILDING

    10.00

    (19 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Car Ports
    Equestrian Stable
    Concrete Garages
    Call
  • LFB Contractors Ltd Logo

    LFB Contractors Ltd

    10.00

    (15 reviews)

    Operates in Mountain Ash

    Services & skills
    Builder
    Extensions / Conversions
    Cladding
    Refurbishments
    Fire and Flood Renovation
    Call

Conversion and extension builders in Mountain Ash

Planning a loft conversion, garage makeover or full house extension in Mountain Ash? 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 Mountain Ash

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 Mountain Ash

Our checked tradespeople in Mountain Ash 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

Extension and conversion build costs in Mountain Ash

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

Extensions:

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Loft conversions:

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Garage conversions:

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Conservatory roof conversions:

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Need help calculating costs? Use our Job Value Estimator Tool for a bespoke cost estimate.

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 Mountain Ash: 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 Mountain Ash

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 Mountain Ash? Enter your postcode or post a job to find emergency services in your area.

Find the right extension or conversion specialist in Mountain Ash

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

Start your search now


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