How much does a House Extension Cost in Kent?

There are many things to think about when it comes to house extensions; What you want and the cost are obvious concerns. Read below to find the most popular choices and give you some idea of what is involved and use our free construction cost calculator.

The 2 Most Common Extensions


Basic single story extension (4m to 5m)

The build for this is around £35,000. You will need to include 12 -15% for the extra fees for professional input. This will include the architect, planning application, building regulations and structural engineer. VAT will be about £6,200

To narrow the costs down a bit; for every m2 is about £1,500. If you build in London and the South East it will be more expensive, around £1,800 to £2,200 per m2

To take all these costs together, the overall build amounts to about £45, 500 for a single story extension.


Basic Double story extension

This will cost around £50,000 for the build, The same percentages apply for the extra professional costs (12 -15%). VAT will be around £9,400. Overall cost is estimated at £65,750.

The above figures will assume an extension that is uncomplicated. You must be aware that depending on what you want, these expenses could increase.
I have listed some examples.
£5,000 depending on sanitary ware and finishes

£10,000 for a mid range kitchen and appliances

Finishes and fittings
£5,000 for sliding or folding doors with a 2.5m width opening

Any luxury finishes such as tiles and fitted joinery will increase your costs. The cost of the build includes modest fittings, electrics, lightning, painted walls and carpet floors or engineered oak.


Extra Expenses to be Aware of

• Soil type and ground costs that involve more construction techniques

• Limited access; consider the possible difficulties bringing in tools and machinery

• If structural walls are to be removed, there will be extra costs for steelwork

• If any pipework, gas meters or drainage facilities have to be moved extra cost of doing this will be incurred.


Quality of Construction

When it comes to ensuring quality, it is highly advisable to hire a good architect. They can assist you with the following;

• They will help you get the extension you want
• They will assist you in controlling costs
• They will work with you to h help you get the most out of your budget and make recommendations. They can also advise on ways to minimise costs
• They will assist in getting quotes from builders and compile a tender list for you which will help to calculate overall costs
• They can inspect the builders work and help you with the building contract. They will also ensure the work is complying with the agreement.

If you plan to do some of the work yourself, there is a good informative website
called 'building supplies online' that can offer trade prices for supplies. This could be useful for things like tiling, kitchen and bathroom fittings and flooring.

Contractors and designers can often access trade discounts so it is always worth shopping around to save money.


Free Construction Cost Estimator

Home Extension Construction Cost Calculator

  • Construction Cost incl. VAT
  • VAT 20% Excluding VAT
  • Professional Fees Based on average complexity
  • Initial Consultation

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