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Building an extension or making structural alterations to your home can often add significant value to your property – especially if an additional room is created, be it a bedroom, garage or extended living space. Before you begin, allocating a budget for the building work is essential. But costs can often increase if you hit a problem along the way. Follow our guide to control your home improvement costs…

How much should I expect to pay?

Adding a bedroom and a bathroom through an extension or loft conversion can increase a property's value by more than 20%, according to Nationwide[JF1] .

Moving to a bigger home is a costly expense, that’s why many of us are putting a similar sum towards improving and extending our current homes – enjoying the added benefit of our properties increasing in value.

But the cost of home improvements can vary depending on:

  • Where you live in the country
  • If there are building requirements e.g. using a specific type of brick / stone
  • How much labour is required

Research from Whatprice revealed the average UK cost for a single storey extension is £23,381, while a double storey extension is £47,052.  A significant amount of money, but a worthwhile investment for many expanding families.

Before the work begins:

  • Use an approved contractor and ask for references from their previous customers to ensure the work will be to a standard you expect
  • Set a price and once agreed, put it in writing, signed by both parties
  • Where there is no set final price, ask for a contract that agrees no additional work is to be carried out until the costs and timescale are agreed and signed
  • Don't pay all the money upfront – agree in writing on a payment schedule
  • Check for manufacturer’s guarantees – to see if they will repair or replace an item that becomes defective within a stated amount of time
  • Check also if the builder or contractor offers you an insurance-backed guarantee for the work
  • Depending on your property and the work you're having done, you may also need planning permission or building regulations approval. If your house is listed or you live in a conservation area you may also need other types of permission.

Always contact your Local Planning Authority (LPA) before any building work begins. If the work you do is not approved by the LPA, you could be served an enforcement notice which orders you to undo all work and changes made.

The biggest home improvement problems

Work taking longer than agreed, mess left behind and problems developing after the work has been completed are the three biggest complaints with home improvements, according to one survey by Which?

What type of jobs caused the most complaints? Loft conversions, although small in number, were most problematic with seven in 10 people having problems; those adding a conservatory, having a new bathroom or kitchen also had issues to sort out.

Unexpected expenses

There are certain circumstances you cannot plan for. In any home improvement project, there can be unforeseen problems that you weren’t able to factor into your budget, such as emergency repairs that need carrying out if something goes wrong.

As such, before you begin any project it is wise to set aside some contingency funds, which can cover you in case of emergency.

If you still need to cover any costs that weren’t expected, Satsuma Loans may be able to help. Satsuma Loans offer short-term loans to help people spread the cost of unexpected expenses by repaying in monthly or weekly instalments. You can choose to borrow from £100 - £1000 and repay over 3-12 months.

We won’t charge you any fees, ever; just repay the amount you borrowed plus interest. The total amount you agree to when you take out the loan will never change.


Representative example: £480 loan repayable over 9 months. 9 monthly repayments of £106.56. Rate of interest 133.1% p.a. fixed. Representative 535% APR. Total amount payable is £959.04