8 things to consider before building a House Extension

House extensions are always challenging, yet the rewards of a successful extension always outweigh its drawbacks. Unlike a brand new house build, with an extension, you are never starting with a blank page, which means you will have many additional factors to consider and obstacles to work around, 

In order to ensure your project turns out to be a resounding success, we’ve put together a list of 12 important things to consider before pulling the trigger on your house extension project. 

1. Will a house extension add value to your home?

This one may sound very obvious, but you want to make sure your house extension will actually help increase the market value of your property. You’ll need to calculate whether the total cost of your extension build will be more or less than the value added. This is easier said than done, as you never really know how much your property will fetch until you get an estate agent’s assessment or see what offers come in once you put it on the market. However, the easiest and most common way of doing this is to take a look at how much some similar properties in your area sold for and compare them to yours. 

2. Know which building regulations will affect your project.

This one is an absolute must, as if you neglect your local building regulations you will be breaking the law, which could result in your local council ordering you to tear down your extension! This is the last thing any homeowner wants to deal with. Although some smaller and less complex extensions can be built under Permitted Development rights, you will still need to obtain Building Regulations approval before going ahead. The following aspects of your build will need to at least meet the minimum requirements:

  • Structural integrity
  • Fire safety 
  • Energy efficiency
  • Damp proofing
  • Ventilation
  • Various other aspects to ensure the building is safe

3. Is your designer a trusted industry expert?

Your choice of designer could make or break your house extension project. Partnering up with a reputable designer will not only ensure that your extension design looks good and is attuned to your personal vision of your property, but will also help you avoid any pitfalls such as structural problems, energy inefficiency and other issues down the road. There are a few different types of designers to choose from including architects, architectural technicians, design specialists and building company’s in-house teams – each with its own strengths and weaknesses. 

professional architect


4. How can you maximise energy efficiency?

This point ties in with the above and an experienced designer will help you to get the most out of your property when it comes to energy efficiency. Good insulation, electrical efficiency, damp resistance – these are all important things to consider and will minimise the long-term cost of your extension. However, it is also important to ensure the rest of your property is already ticking all of these boxes and if it is not then you may want to consider having some work done on the rest of your property. 

5. Does the Party Wall Act of 1996 affect your plans?

Carrying out building work within a certain distance of the party wall between your and your neighbour’s property will require you to adhere to the regulations laid out in the Party Wall Act. This includes excavating or building foundations within 3 meters of the boundary, party wall or structure, or 6 meters if a 45° will be formed between the bottom of your new foundations and those belonging to your neighbour. The good news is that the Party Wall Act is rather easy to work around and a surveyor can quickly inform you of how you will be affected and how to design in accordance with these regulations. 

6. Does your current boiler have the capacity to support a house extension?

Now, this one is usually not a problem for 99% of homeowners, however, you still need to make sure that your boiler can actually meet the extra demand from any additional heaters or under-floor heating. Your boiler could already be working at or close to its maximum capacity and you want to avoid any nasty surprises. 

boiler capacity


7. Will your extension match the rest of your property?

Interior design is not the only aesthetic design choice to consider and you will need to decide how you want to approach decorating your extension’s exterior. Will it blend seamlessly with the old parts of the property to give the illusion of having always been there or will you go for a more contrasting option to make it stand out and add some extra character to the overall look of your property’s exterior? There really is no right or wrong way of doing this and how you should handle this decision will depend mostly on personal preferences and your personal vision.

8. Are the trees in your garden protected by TPOs?

Tree Preservation Orders (TPOs) are orders made by the local planning authority which forbid you from cutting down or altering certain trees in order to protect them from damage or total destruction. Even if your house extension does not require planning permissions, trees protected by TPOs cannot be cut down to make room for your extension and you must make an appeal to get written consent to do so. Breaking this law can leave you subject to a heavy fine, so make sure you have the green light before making any alterations.

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Everything you need to know is right here!

Construction work can be complex and a little confusing for those outside of the industry. We want our customers to have clarity when it comes to understanding the different aspects of construction work we carry out and what is important to consider when planning on having work done on your home. That’s why we have created a catalogue of useful articles with the help of industry experts as well as our own team – to share our knowledge and keep our customers informed, aware and confident in their decisions.

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