How to Build a House Extension


If your house is bursting at the seams and no amount of decluttering will sort it out, you may be wondering about how to build a house extension.

In this age of working from home and intergenerational living, building an extension could give you more family space, a home office or an extra bedroom.

Extending your existing house may be preferable to moving house as it could save money on stamp duty, solicitors fees and higher mortgage payments. Not to mention the anxiety surrounding moving house, which research suggests can be one of life’s most stressful experiences.

Adding an extension could also add to the asking price of your home when you decide to sell.

Extension projects require careful planning, so let us help you through the process.

How to start planning a house extension

If you are unsure about how to start planning your house extension, it is a good idea to consult a building contractor or a company like PCL to discuss your requirements.

You will need to be clear about why you need a home extension.

How will you use your proposed extension, and what would you like it to look like? Do you need a playroom for the kids, an office for a homeworker or a private room for an elderly relative or boomerang child? Would a two-storey extension at the front of your original house or a single-storey rear extension provide the extra space you need?

Extra space may not be the only benefit of your extension project. There may be the potential to mix old and new spaces by removing a rear wall, creating a large open-plan space and flooding your home with natural light.

Materials to use in your house extension

Your original home may have been constructed using bricks and mortar, but there are other options for you to consider.

Our SIP Panels are particularly suited for a single-storey extension and will significantly reduce your extension costs.

SIP panels comply with all building regulations and offer the same insulation as brickwork. They are thinner than a traditional cavity wall, so they give you a little more floor space too. You can cover your SIP extension in brick cladding or render to complement the appearance of your existing house.

Build costs can spiral during a traditional build, but you can get a fixed quick quote from our website to give you an idea of the cost of a SIP extension for your home.

How to design an extension for your house

The internet is full of videos on how to design a house extension, but for most people, it is a good idea to involve professionals in the design of your extension project.

The team at PCL are highly experienced in building all types of extensions with SIP panels. Our previous extension projects include conservatories, annexes, washrooms, garage conversions and more. We can work with you from your own drawings or design the extension for you.

If you are planning a larger extension involving the removal of retaining walls or party wall agreements, you may need professional design help from an architect or structural engineer to ensure that your plans comply with current building regulations and make the most of your space safely.

Will I need planning permission to extend my existing house?

You may be able to build your extension without applying to your local planning authority for planning permission.

Currently, homeowners are allowed to build a single-storey extension to the rear wall and the sides of their property under permitted development rules. The rule is that your new extension should not have a negative effect on your neighbours or the local environment.

Permitted development rights allow you to build out four metres from the rear wall of your existing property if you have a detached house and three metres in a semi or terraced house.

Different building regulations may apply if your original house is in an area of outstanding natural beauty or requires a listed building consent.

In most cases, it is a good idea to contact your local authority planning officer to check whether you need planning permission or not. You can find more details about planning permission and your rights here.

How to build your own house extension

Some people successfully build their own house extensions. As with designing your extension, a quick internet search may provide lots of ideas on how to build a house extension.

In reality, people who successfully extend their homes themselves usually have experience as a building contractor or project manager.

Knowing how to build adequate foundations or how to join an extension to a house requires a high level of knowledge and expertise if you want to avoid problems with the building inspector.

There is also a time and inconvenience factor. Extending your house could take months, causing disruption and possibly some frustration from other family members during the extension process.

Compare this with the experience of PCL customers who can move into their beautiful extension within weeks.

If you choose an extension from PCL built with SIP panels, you can leave all the project management to us.

How to build a house extension step by step

The key stages of your extension project are:

Deciding what sort of extension you want: choosing your building method; engaging a building contractor or architect if required; checking whether your build comes under permitted development; applying to your local planning authority if necessary and finally, the building process.

Alternatively, contact PCL for more information on an SIP extension that will increase the useful space in your home with minimal inconvenience and at a great price.

You can browse our website for more details or ring our friendly sales team for advice on 0161 300 4900


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