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The beautiful, residential district of Forest Hill is a dream neighbourhood. Boasting of summer concerts, classical Victorian homes, and the ever-popular Horniman Museum, it is easy to see why Forest Hill residents are considered to be the lucky ones.

So, when increasing family sizes and changing lifestyles require a change in one’s living space, house extensions in Forest Hill provide a simple solution.

From adding extra bedrooms to transforming the attic space, home extensions allow homeowners to design and create bespoke spaces that are specific to their needs, without having to endure the heavy cost and inconvenience of moving houses.

A house extension is essentially a chance for property owners to increase the living space within their homes while also increasing the value of their properties.

Home extensions can be designed and built to cater to the specific needs, requirements, and budgets of homeowners. This makes them uniquely versatile and immensely popular choices for home improvement projects.

House extensions are generally categorised into different types based on the area of the property on which they are constructed. House extensions that are commonly found in Forest Hill include:

Rear extensions

Built on the rear of the property, rear extensions provide plenty of space to create kitchen extensions, guest rooms, playrooms, or office pods.

Side return extensions

Built along the side of the house and with a portion of the rear, side return extensions are ideal for homeowners looking to save their garden space. These extensions allow you to increase your living space while adding beautiful indoor-outdoor connections that bring in an abundance of natural light and ventilation.

Wrap around extensions

A combination of side and rear extensions, this L-shaped structure ‘wraps’ around the property while adding great width and depth to it. As such, wraparound extensions may be used to create multiple rooms or even open floor layouts.

Multi-storey extensions

Doubling the square footage of the extension without increasing the roofing and excavation costs is what makes double storey extensions extremely appealing. That’s not all. These extensions also allow you to create additional bedrooms, bathrooms, or even high-ceilinged living and dining areas.

Most home extensions constructed in Forest Hill will not require planning permission if they fall under permitted developments. Some of the criteria and specifications for permitted developments include:

  • Side extensions must be single-storied and must not exceed more than half the width of the original house.
  • Extensions must not be higher than the highest part of the existing roof.
  • The materials used on the exterior of the extension must be similar in appearance to the materials used on the exterior of the original house.
  • Extensions must not take up more than half the land around the original house.

However, extensions that do not fall under permitted developments, and those constructed on properties listed in conservation areas, will require planning permission.

Applications for planning permission require detailed diagrams of the proposed extension and may take up to eight weeks to process.

In addition to planning permission, building regulations approval and party wall agreements also need to be considered. These ensure that the proposed build meets the building guidelines and standards.

Good Design and Build oversees this entire process for our clients. From surveying the location, submitting a comprehensive application which includes structural diagrams and calculations, coordinating with the local authority, and securing the requisite planning permission and necessary approvals.

Based on the area available and the design requirements, house extensions in Forest Hill generally feature:

Loft Conversions

For growing families, an extra bedroom can be a valuable addition. And loft conversions are perfect for achieving exactly that.  Loft conversions also have great versatility in how they are designed and utilised.

Kitchen Extensions

Kitchen extensions are one of the most sought-after extension types in Forest Hill. This is because kitchen extensions add great value to a property and are ideal for converting an old-fashioned space into a warm and inviting room perfect for hosting in a modern home.

Refurbishments

Extensions may not always be the only solution to a space problem. The inside space of a home can be completely transformed by remodelling and refurbishing it. This involves changing the floor plans to create open spaces and optimising the potential of a room by maximising the natural light that enters it.

The cost of a house extension in Forest Hill is dependent on a number of factors including:

  • The size of the extension
  • The design/ complexity of the extension
  • Location
  • Groundwork involved
  • Building materials
  • Planning permission fee
  • Fittings and fixtures
  • Specialists’ fees, etc.

As a result, the cost of a house extension in Forest Hill can range from £35,000 to £140,000.

Good Design and Build offer free consultations and quotations for proposed extensions. This allows homeowners to plan, design, and create bespoke extensions within their intended budgets.

House extensions in Forest Hill are the perfect remedy to resolve space issues in your otherwise ideal home. But in order to be worthy of the investment, they need to be built with careful planning and meticulous attention to detail.

This is why Good Design and Build are the preferred home extension builders in South London. We boast of a team of experts with years of experience in designing and building high-quality extensions that come backed by warranties.

Our incredible team comprises of project managers, architects, surveyors, builders, and technicians. This allows us to provide complete project management of the entire extension process from start to finish.

All of this ensures that we not only create exceptional extensions for you, but also provide you with a fantastic, stress-free experience.

Don't move. Extend in style

We can save you the hassle that comes with moving not to mention the heavy stamp duty! Adding an extra loft bedroom or enlarging the living kitchen dining space on ground floor is an economical way of transforming your home to suit growing needs. The projects can range from £40-100K depending on your requirements and can be completed within 8-16 weeks.

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How we deliver projects

Our process is simple and divided into two distinct phases with separate contracts: Design and Build. As a client you only commit to one phase at a time depending on what stage of the process you are in. Each phase consists of three stages as described below.

1. Design

This is the kick-off point for your project. We carry out a complete architectural measured survey of the property. This allows us to create accurate CAD design drawings. This is followed by a design meeting to start discussing your ideas in more detail.

2. Planning

At this stage we finalise the designs with you and start preparing planning applications as needed. We place a high priority on ensuring that plans, designs and schedules are all based on a thorough and detailed understanding of planning guidelines. We co-ordinate with local authorities until the decision is made, and the planning approval is secured.

3. Technical

Once the planning consent is secured, we translate the design drawings into more detailed technical drawings for the purposes of building control and construction. This also includes specifications and structural calculations. At this stage, we will also submit to you our ‘no obligation’ quote for the build phase.

4. Pre-build

90% of our clients decide to stick with us after the design phase is completed. Once the build contract is signed, we kick off the process by making sure all the pre-build processes are complete. These include assistance with party wall agreements, Thames Water build over agreement, submitting building control application, and preparing method statements etc as needed. This stage ends with a pre-start meeting with your foreman before the actual build begins.

5. Build

One of our foremen will be dedicated to your project and will be on-site to manage everyday works. Our project managers will be overseeing the works to make sure they are completed to high standards, within your budget and on time. Throughout the process we will keep you updated with the progress and coordinate the works with third parties such as kitchen or flooring suppliers. We will also advise and guide you to choose any suppliers if needed.

6. Handover

As the build draws to finish, we will help to iron out any ‘snags’ to make sure everything is completed to your satisfaction. We will put together all necessary certificates such as gas, electricity and building control completion along with warranties for glazing, boiler etc. At the final completion meeting, we will hand you these documents, together with the keys to your house. Needless to say, you can contact us any time after this, if you want us to look at something.


This is the kick-off point for your project. We carry out a complete architectural measured survey of the property. This allows us to create accurate CAD design drawings. This is followed by a design meeting to start discussing your ideas in more detail.

At this stage we finalise the designs with you and start preparing planning applications as needed. We place a high priority on ensuring that plans, designs and schedules are all based on a thorough and detailed understanding of planning guidelines. We co-ordinate with local authorities until the decision is made, and the planning approval is secured.

Once the planning consent is secured, we translate the design drawings into more detailed technical drawings for the purposes of building control and construction. This also includes specifications and structural calculations. At this stage, we will also submit to you our ‘no obligation’ quote for the build phase.

90% of our clients decide to stick with us after the design phase is completed. Once the build contract is signed, we kick off the process by making sure all the pre-build processes are complete. These include assistance with party wall agreements, Thames Water build over agreement, submitting building control application, and preparing method statements etc as needed. This stage ends with a pre-start meeting with your foreman before the actual build begins.

One of our foremen will be dedicated to your project and will be on-site to manage everyday works. Our project managers will be overseeing the works to make sure they are completed to high standards, within your budget and on time. Throughout the process we will keep you updated with the progress and coordinate the works with third parties such as kitchen or flooring suppliers. We will also advise and guide you to choose any suppliers if needed.

As the build draws to finish, we will help to iron out any ‘snags’ to make sure everything is completed to your satisfaction. We will put together all necessary certificates such as gas, electricity and building control completion along with warranties for glazing, boiler etc. At the final completion meeting, we will hand you these documents, together with the keys to your house. Needless to say, you can contact us any time after this, if you want us to look at something.

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Build a Quote!

Let's get started with building your own bespoke quote for your dream extension. Tell us as much in detail as possible to get most accurate price.

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Build a Quote!

Let's get started with building your own bespoke quote for your dream extension. Tell us as much in detail as possible to get most accurate price.

Get Started