Separate the house problem from the location problem.
If you love the neighbourhood but need a better kitchen or another family room, extending may be worth exploring. If the issue is the commute, school location, parking or a garden that cannot meet your needs, more floor area may not solve it.
Write down what must change and what you would be reluctant to give up. Judge both options against the same priorities.
Compare whole costs, not headline prices.
For an extension, allow for construction, VAT, design, engineering, permissions, fit-out, temporary accommodation where needed and a contingency. Our cost guide gives you a starting budget.
For moving, consider transaction taxes where applicable, legal fees, survey costs, selling fees, removals and work needed at the new home. Obtain current professional advice for your circumstances rather than relying on a standard percentage.
Test what your existing plot can deliver.
An extension should leave usable outdoor space and a comfortable relationship with neighbours. Planning restrictions, drainage, access and the existing structure can change what is practical.
Before paying for a fully developed design, a site discussion and planning review can help establish whether your preferred layout is realistic.
Think beyond the finished photograph.
Consider disruption, financing, maintenance and how long you expect to stay. Neither extending nor moving guarantees a financial return; speak to a local valuer if resale value is important.
Choose the option that fits your family and budget, with a clear scope and realistic allowances before you commit.
Further reading: GOV.UK: buying or selling your home
