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House Extensions: 6 Essential Factors to Consider


Taking up a home extension is a super rewarding process with fruitful results that increase the square footage of your property, boost the value of your home by up to 25%, and improve your living standards and lifestyle. But, at the same time, it is a financially and emotionally taxing procedure. So before you call in professionals and swing the first hammer, there are a few essential considerations to evaluate and understand for a successful project.  Read on to learn more about the top 6 things to consider before going ahead with a house extension.

Taking up a home extension is a super rewarding process with fruitful results that increase the square footage of your property, boost the value of your home by up to 25%, and improve your living standards and lifestyle. But, at the same time, it is a financially and emotionally taxing procedure. So before you call in professionals and swing the first hammer, there are a few essential considerations to evaluate and understand for a successful project.


Read on to learn more about the top 6 things to consider before going ahead with a house extension.


Create a Budget


You’ve obviously set aside a particular amount of money for the extension, but have you made sure that the budget will fit every major and minor requirement of the project? While most people tend to focus on the contractor fees and materials, there’s an extensive list of hidden costs that are overlooked, including legal fees, stamp duty, architecture fees, structural engineer fees, warranty, waste removal, external works, etc.   A detailed insight into the budget where you write down all expenses, allocate money to each, and plan for emergency costs will save you from a lot of hassle down the lane.  To get a strong sense of total costs involved with your extension (and to avoid surprises down the line), chat with one of our Quantity Surveying Gurus that can guide you over video call and create an Early Cost Estimation for you!  See Where You Can Save  You can save a good buck with decent know-how about power tools. The more tasks you do yourself, the more you will save on labour costs. DIY-ing will also give you greater control over the project, the material quality, and the standard of the work. However, this might extend the timeline of the build.

You’ve obviously set aside a particular amount of money for the extension, but have you made sure that the budget will fit every major and minor requirement of the project? While most people tend to focus on the contractor fees and materials, there’s an extensive list of hidden costs that are overlooked, including legal fees, stamp duty, architecture fees, structural engineer fees, warranty, waste removal, external works, etc.


A detailed insight into the budget where you write down all expenses, allocate money to each, and plan for emergency costs will save you from a lot of hassle down the lane.


To get a strong sense of total costs involved with your extension (and to avoid surprises down the line), chat with one of our Quantity Surveying Gurus that can guide you over video call and create an Early Cost Estimation for you!

See Where You Can Save


You can save a good buck with decent know-how about power tools. The more tasks you do yourself, the more you will save on labour costs. DIY-ing will also give you greater control over the project, the material quality, and the standard of the work. However, this might extend the timeline of the build.


Set a Timeline


Home extensions are not a quick job. In fact, you’ll be surprised when you find out how long home extensions can take even to begin — let alone be completed. The planning permissions, for example, might take up to 8 to 10 weeks, while reaching a party wall agreement with the neighbours can take 2 to 3 months.   Other typical tasks like the time required for survey and design, the planning process, producing working drawings, and mobilising a contractor will result in an average timeline of about 7 to 15 weeks for the project to be completed.

Home extensions are not a quick job. In fact, you’ll be surprised when you find out how long home extensions can take even to begin — let alone be completed. The planning permissions, for example, might take up to 8 to 10 weeks, while reaching a party wall agreement with the neighbours can take 2 to 3 months.


Other typical tasks like the time required for survey and design, the planning process, producing working drawings, and mobilising a contractor will result in an average timeline of about 7 to 15 weeks for the project to be completed.


Check the Existing Services


The services of your home include electricity, gas, water, and drainage. When planning an extension, it is important to check if these services will be impacted during the process. If the answer is yes, you will need to shift essential requirements to another area, like creating a mini kitchen and a temporary bathroom solution elsewhere. For more extensive projects like where the electricity will be disrupted, relocating might be more convenient.

The services of your home include electricity, gas, water, and drainage. When planning an extension, it is important to check if these services will be impacted during the process. If the answer is yes, you will need to shift essential requirements to another area, like creating a mini kitchen and a temporary bathroom solution elsewhere. For more extensive projects like where the electricity will be disrupted, relocating might be more convenient.


Incorporate Sustainability


Looking for ways to incorporate sustainability in your home extension will go a long way in reducing your carbon footprint while making your home more economical in terms of electricity and thermal costs. Remember, a home extension is also an opportunity to repurpose the rest of your home.   From cavity wall insulation and loft insulation to energy-efficient windows and solar panels, there are countless ideas to make your home eco-friendly and comfortable.   For expert guidance on your home's sustainability, chat with one of our Eco & Sustainability Gurus who can give you ideas, help you weigh options, and educate you on the true environmental impact of your decisions.

Looking for ways to incorporate sustainability in your home extension will go a long way in reducing your carbon footprint while making your home more economical in terms of electricity and thermal costs. Remember, a home extension is also an opportunity to repurpose the rest of your home.


From cavity wall insulation and loft insulation to energy-efficient windows and solar panels, there are countless ideas to make your home eco-friendly and comfortable.


For expert guidance on your home's sustainability, chat with one of our Eco & Sustainability Gurus who can give you ideas, help you weigh options, and educate you on the true environmental impact of your decisions.

Look Out for Potential Obstacles


Apart from the construction plan and layout of the home extension, looking out for potential obstacles around the home is equally important. Some trees (known as TPOs) are protected. If your garden (or a nearby area) has a protected tree included in the extension’s square footage, you will lose permitted development rights and will need planning permissions. Obstacles like sewers under your home and conservation areas can be other causes of concern.   A perfect way to anticipate potential obstacles, without breaking the bank, is to have a chat with one of our Architecture & Planning Gurus. They will be able to review your plans and look at your space over video call, and give you expert guidance.

Apart from the construction plan and layout of the home extension, looking out for potential obstacles around the home is equally important. Some trees (known as TPOs) are protected. If your garden (or a nearby area) has a protected tree included in the extension’s square footage, you will lose permitted development rights and will need planning permissions. Obstacles like sewers under your home and conservation areas can be other causes of concern.


A perfect way to anticipate potential obstacles, without breaking the bank, is to have a chat with one of our Architecture & Planning Gurus. They will be able to review your plans and look at your space over video call, and give you expert guidance.

View Building Regulations


When you’re done with winning permissions, permits, and inspections, it is time to sort out the building regulations. Ask your architect or structural engineer to commission a building regulations package. They will pull together a highly detailed set of drawings to cover all the required safety standards, including fire safety, toxic substances, ventilation, sound, hygiene, drainage, electrical safety, and so on. This will save you from penalty fines or even more expensive problems like being asked to demolish the entire extension.

When you’re done with winning permissions, permits, and inspections, it is time to sort out the building regulations. Ask your architect or structural engineer to commission a building regulations package. They will pull together a highly detailed set of drawings to cover all the required safety standards, including fire safety, toxic substances, ventilation, sound, hygiene, drainage, electrical safety, and so on. This will save you from penalty fines or even more expensive problems like being asked to demolish the entire extension.


Final Words


Doing a home extension is a big decision, and it's important you know exactly what you're getting into. By tapping into expert knowledge and insights during your journey, you will be able to anticipate the upcoming process, and avoid any negative surprises.


Having a professional handle your full project can be expensive, but thankfully, there are innovative solutions like HiiGuru, that allow you to access expert support in a flexible manner, helping reduce professional fees significantly.


If you'd like some personalised advice, why not chat with one of our RIBA Chartered Architects who can give you expert guidance and support you throughout your home extension process, at a fraction of the cost?
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