House extensions

A construction worker stands on scaffolding while building a brick extension to a house, where sash window repair South London services may soon be needed. Wooden beams and building materials are scattered around the site.

Expand Your Home with a Bespoke Extension

At 1st Builders Cambridge, we specialise in creating house extensions that add space, comfort and lasting value. Whether you’re looking for an open-plan kitchen, a ground floor bathroom, a guest suite or simply more room for your family, we deliver solutions designed around your home and lifestyle.

We offer single-storey, multi-storey and above-garage extensions, managing every stage from design and planning to construction and finishing. Our team also liaise with local authorities on planning permission, making the process as smooth and stress-free as possible.

With a focus on quality craftsmanship and attention to detail, we ensure your extension blends seamlessly with your existing property. Most of our projects come through recommendations, reflecting our commitment to customer satisfaction and professional results.

Types of House Extensions:

  • Single-storey rear or side extensions
  • Multi-storey extensions
  • Over-garage extensions
  • Wrap-around extensions
  • Conservatories and orangeries

What We Handle for You:

  • Full design and planning service
  • Planning permission applications
  • Foundations and structural work
  • Plumbing, electrics and heating
  • Roofing, windows and doors
  • Plastering, decorating and flooring

Benefits of a House Extension:

  • Add significant value to your property
  • Create open-plan living and modern layouts
  • Extra bedrooms, bathrooms or office space
  • Enhance comfort without the cost of moving
  • Extensions designed to blend seamlessly with your home
Several workers construct a timber roof frame on top of a partially demolished brick building, with scaffolding and tools visible around the site.

Structural Alterations in Progress

This stage shows the careful integration of new structural beams and timber supports around the existing chimney stack. Our team ensure every detail is completed with precision, creating a strong and stable framework for the new extension while maintaining the character of the original property.

 

 

Key steps at this stage include:

  • Installing RSJ steel beams for strength and load-bearing support
  • Adding new timber joists and rafters to extend the roofline
  • Reinforcing existing walls and structural points
  • Preparing safe access and scaffolding for the build

Contemporary Rear Extension

This modern single-storey rear extension adds both space and style to the property. Built in brickwork to match the existing home, it features sleek doors and windows that open directly onto a newly finished patio. The design creates a seamless flow between the indoor living space and the garden, making it perfect for everyday family use as well as entertaining. Durable, practical and visually appealing, this extension enhances the home’s comfort while adding long-term value.

Key Features:

  • Matching brickwork for a seamless finish
  • Large patio doors for easy garden access
  • Integrated with a newly landscaped outdoor area
  • Built for durability and year-round comfort
A modern brick outbuilding with glass doors and steps stands next to a grey storage shed, tiled patio, and artificial grass area under an overcast sky—ideal for those seeking Sash Window Repair South London expertise.

FAQ

How much value will an extension add to my house?

While this varies, a well-designed extension almost always adds more value to a property than it costs to build. Kitchen-diner extensions are particularly valuable. It’s a fantastic investment that also gives you more space to enjoy.

We take great care to match new materials, such as bricks and roof tiles, to your original property. Our goal is to make the extension look like a natural part of your home, rather than an obvious addition.

We do everything we can to minimise disruption. We will seal off the work area from the rest of your house and create separate access for our team where possible. We aim to break through into the main house only when absolutely necessary, typically towards the end of the project.
 

A single-storey extension adds a room or rooms on the ground floor only. A two-storey extension adds rooms on both the ground floor and the first floor, often creating a new bedroom and bathroom above a new kitchen or living area, offering maximum space for a similar footprint.

Yes, installing bi-fold or sliding doors is one of the most popular features of modern extensions. They create a fantastic connection between your home and garden. We manage the entire process, from creating the structural opening to fitting the doors perfectly.
 
 

For a complex extension, an architect is highly recommended to produce detailed drawings. For more straightforward projects, we can often work with you directly or with a more affordable architectural technician to produce the necessary plans for planning and building control.

Building Regulations are minimum standards for design, construction, and alterations to virtually every building. They are completely separate from planning permission and are essential for ensuring safety and energy efficiency. All our extension work is fully compliant and will be signed off by a local authority or approved inspector.

Yes, we frequently build extensions on terraced properties. This requires careful logistical planning for access and material storage, as well as adherence to the Party Wall Act to ensure your neighbours are formally notified and protected.

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