Should you demolish your house and build a bigger one, or extend and renovate it?

Large two storey house extension

If your family is growing and your home is starting to feel too small, you usually have three options - knocking down a house and build a bigger one, extend and renovate your home or move to a bigger property.

Moving tends to be difficult due to work commitments and children going to school, which leaves you with two options. But which one is better? 

We’d love to give you a straight answer, but there are too many factors at play. If you’re reading information which does provide a definitive answer, take time to check the source. Does the company specialise in just new builds? Do they only complete loft conversions?

As one of the leading Construction companies in North London, we frequently carry out new builds, extensions and renovations, which is why we can give you the best advice on what would be the best solution for you.

The most critical elements to consider when choosing between rebuilding or extending and renovation your house:

  • Age, condition and structural quality
  • Plot location and size
  • Budget
  • Design freedom
  • Time and logistics
  • Your desires
  • Glazed extension on a period property

    Age, condition and structural quality  

    The age and condition of the property is an excellent starting point for your considerations.

    However, again it is impossible to be prescriptive. We have undertaken renovation and extension projects on older period properties, whilst we’ve also recently demolished and rebuild a relatively new house as it was too dark and gloomy.

    The condition of a property can determine the costs of renovation. Is there a great deal of structural work to complete? If yes, knocking down the house and building a new one could be a good option. This is particularly true if there are large-scale safety or preservation works which need completing which have minimal effect on your ultimate design.

    Or perhaps you have chosen this home precisely because you value its age and character. If so, then seek a way that will enhance the property’s character while also meeting your objectives. As strange as it sounds, a highly glazed extension could the perfect solution. 

    It can be useful to have a detailed structural survey at this stage to help guide your decision.

    Luxury new build house in Hertfordshire

    Plot location and size 

    Often deciding about whether to demolish and rebuild or extend is determined mainly by the size and location of the plot and planning considerations.

    The plot itself can determine your options. For example, if you have a structurally good condition detached property in a good size plot, then extending and interior renovation makes sense. If you have a townhouse style terrace, then a loft extension may be the solution. Alternatively, if you’ve purchased a house to secure the plot but you don’t love it, and it’s in disrepair, then rebuilding makes the most sense.

    You will also need to consider the planning considerations for your property and area. For example, if you live in a conservation area, demolishing the property will be difficult or even impossible.

    Again this is where it is worth speaking with experienced London construction companies that know your local area and will be able to advise on which options are going to face the least planning resistance. 

    House with a face brick house extension


    This is where unbiased advice is invaluable. Seek preliminary advice from experts, such as Marriott Construction Ltd., who can give you a ballpark figure regarding your different options. Budget alone may determine which course of action you take.

    A full house renovation, especially if it entails extension work, might be more expensive than starting again. This is actually largely due to VAT. All renovation work will be subject to VAT at 20%. When you build a new property, this can be done at 0% VAT. However, the largest costs are typically structural. Therefore, if you’ve got a structurally sound property and you’re out to change the ‘look’ alone then renovation could well be more economical.

    General figures per square metre include:
    Rebuilding costs in London:  Approx £3000 per sq m.
    Extension costs in London:  Approx £2000 - £3500 per sq m.
    Loft conversion costs in London:  Approx £1500 - £3000 per sq m.
    Renovation costs in London:  Greatly variable depending on structural condition and scope of works.

    Large open plan kitchen in a new build home

    Design freedom

    Clearly, a new build allows you input in to every element of design. You can design your new home in entirety (subject to planning constraints). Working with the existing property will require compromises.

    When considering your design, keep your eye on your aspirations. Your home needs to work for your lifestyle. Therefore, don’t try to copy what others on the same street have done, but think about what actually matters to you.

    A good starting point here is deciding how much does the existing layout and style match what you hope to achieve? The greater the gap between where you are, and where you want to be, the more likely it is that you need to consider a rebuild. However, if it is largely suitable in the main then an extension and/or renovation could be more suitable.

    Large shaker kitchen in a home extension in London

    Time and logistics

    Different options will take different lengths of time. Surprisingly, new builds can be faster than renovation and extension work. There are a number of reasons for this.

    Firstly, the owner won’t be living in the property. Whilst working around the owner is often possible, it can delay progress.

    Secondly, much of the new build ‘time’ is taken in planning. Once building commences, it is fast and to plan. However, with renovation, you aren’t always able to know the precise amount of time required. Problems can crop up, which add more time.

    With that said, you will also have to consider logistics. While your house is being renovated, you might still be able to live there. When rebuilding, you will need to find another place to stay for the duration of the works, adding to the cost.

    Interiors in a fully renovated house in North London

    Your desires 

    Do you actually want and need more space or are you after a better finish and look? What are your goals from this project? You should consider the following questions:

    * Do we need larger rooms and/or more rooms?

    * Do we need additional bathrooms?

    * Do we need home office space?

    * Is our family growing or changing in the near future?

    * What matters to us most in our home?

    * How does our current home flow? What frustrates us? 

    Hopefully, you are now a little closer to deciding which option is best for you. Choose a trusted building company who can advise you on new builds, extensions, loft conversions, renovation and all elements of home building and design. This will ensure you make the right decision so that your future home is the one you really want it to be. 

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    • 183 Edgware Road
    • London
    • NW9 6LP
    • 2 Athenaeum Road
    • Whetstone
    • N20 9AE

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    We operate across North London, North West London and Hertfordshire. Including BarnetBushey, Camden, Edgware, Finchley, Hampstead, Hendon, IslingtonMill Hill, Potters BarStoke Newington and Watford