In this blog, we discuss whether it’s best to Extend or Move

There’s a reason why, at Modexa Build, we say ‘Love where you live’

A big part of this is that many of our clients choose to extend their existing houses, rather than move to a new house.

We understand that people have an emotional bond with their properties. Houses create memories, after all!

Also, there was a reason why you moved to your current location in the first place. Maybe it was the schools, maybe the people…maybe the local walks (or local pub!).

Over time, you build a connection with your local area. You understand safety implications, know the bus routes, get on first name terms with the shop keepers.

Perhaps it was the house itself that you fell in love with. The garden, the sunshine in the afternoon, the convenience of a downstairs loo!

Clearly then, there can be a set of emotional and practical reasons for staying put. Not least because of the stress and upheaval of a house move. There’s also all of the admin time needed to update contact information.

However, if your house is in need of more room, a different configuration or a granny annex, then you may be contemplating leaving the area for something more suitable. Life changes, and our needs change too.

This leads to that perennial question: Extend or Move?

This then also becomes a question of finances.

There are loads of reasons why moving house is financially burdensome.

There are the fees, the taxes, decoration, repairs…

In this guide, we take an honest look at the cost of the ‘extend or move’ decision. We take into account appreciation of house value, mortgage rates and terms, and the value limit that there may be in a particular area.

We hope you find this guide useful, and would love to hear your thoughts or the Extend or Move debate! 

Let’s model this as a typical “good area Yorkshire / North of England family move”.

You currently own:

• Current home: £340,000 (3 bed) 
• Moving to: 
• New home: £525,000 (4 bed) 

You’ve been in your current house 10 years, so we’ll assume you bought around 2016 and have paid down a chunk of mortgage.

Step 1 – Likely Equity Position After 10 Years

Assumption:

Bought for £340k with 15% deposit in 2016

• Original mortgage approx: £289,000 
• 25-year mortgage 
• After 10 years of repayments, the likely balance today: 

£185,000 – £215,000

Let’s use £200,000 as sensible middle ground.

Step 2 – Equity Released on Sale

Sell current house for £340,000

Less mortgage £200,000

Gross Equity = £140,000

Step 3 – Moving Costs

Buying £525k house

Stamp Duty (England main residence)

• 0% first £125k = £0 
• 2% £125k–£250k = £2,500 
• 5% £250k–£525k = £13,750 

Total SDLT = £16,250

Other Fees

Other Fees Total = £9,200

Step 4 – Usable Equity

£140,000 equity

Less fees £25,450

Usable deposit = £114,550

Step 5 – New Mortgage Needed

£525,000 purchase
Less £114,550 deposit

New Mortgage = £410,450

Step 6 – Likely New Repayments (2026 Rates)

Using approx 5.25% fixed rate

25-Year Term:

Approx £2,460 pcm

30-Year Term:

Approx £2,265 pcm

35-Year Term:

Approx £2,115 pcm

(illustrative based on current market levels) 

Step 7 – Compare to Existing Likely Mortgage

If the current mortgage balance is £200k over remaining 15 years:

Current payment approx:

£1,550 pcm

Monthly Increase to Move

Mortgage Term Extension

If you currently have 15 years left:

• New 25 year mortgage = adds 10 years 
• New 30 year mortgage = adds 15 years 
• New 35 year mortgage = adds 20 years 

Honest Reality Check

To jump from £340k to £525k usually costs:

Cash Gap:

£185,000 price jump

But because of equity, real move cost becomes:

Around £700–£900/month extra for most families.

Smartest Route (What many do)

Take 30-year term now (£2,265 pcm)
Then overpay £200–£300/month when comfortable.

This keeps flexibility but cuts years of payments off the mortgage later.

My Honest Opinion

If household income is:

• £70k joint = stretch 
• £90k joint = workable 
• £110k+ joint = comfortable 

Hidden Financial Win of Extension

You avoid:

• £16,250 stamp duty 
• £9k+ fees 
• Removals / stress 
• New mortgage affordability tests at bigger level 

Immediate saving:

~£25,000 cash

Added Property Value

A good £110k extension in a good area often lifts value to:

£430k – £485k+

(depending on layout and ceiling values)

So you are likely to recover much if not all of your spend in equity.

To add some emotion into the Extend or Move debate, let’s carry out a quick Lifestyle Comparison

Honest Builder/Developer View on Extend or Move:

If your current street supports £450k+ values, the extension often wins.

If your street is capped at £380k max, moving may make more sense.

Real Northern Market Rule

If a £110k extension gives you:

• extra bedroom 
• open-plan kitchen 
• utility 
• office 
• better garden use 

…or even a combination of the above, it can outperform moving massively.

My Straight Opinion

For a £340k house in a good Yorkshire area:

When it comes to deciding whether to Extend or Move, I’d seriously look at extending first, because spending £110k instead of taking on a £410k mortgage is usually stronger financially.

Authored by Ali Gladstone, an actual Human

If you would like to see more blogs from Modexa Build, simply click on the resources page at the top of our home page here: https://modexabuild.co.uk/