Should I Buy to Let?UK property investment calculator

Hypothetical refurbishment case

Does a Year 5 refurbishment improve the investment?

A higher rent is not enough on its own. The works bill, lost rent and timing all belong in the cash flow.

Before the works

Monthly rent£1,650
Collected annual rent at 95% occupancy£18,810
Management fee at 10%£1,881
Service charge and repairs provision£3,500
Mortgage interest£7,500
Normal pre-tax annual cash flow£5,929

Year 5: the refurbishment

Works cost£25,000
Time without rent4 months
Rent collected during the year£13,200
Management fee£1,320
Service charge and routine repairs£2,500
Mortgage interest£7,500
Year 5 cash flow including works−£23,120

Doing nothing would have produced £5,929 in this simplified year. The refurbishment therefore creates a Year 5 cash-flow disadvantage of £29,049—not merely the £25,000 invoice.

From Year 6: higher rent

New monthly rent£2,050
Collected annual rent at 95% occupancy£23,370
Management fee at 10%£2,337
Service charge and repairs provision£3,500
Mortgage interest£7,500
Post-works annual cash flow£10,033
Annual improvement over doing nothing£4,104
Year 5 disadvantage£29,049
Annual improvement£4,104
Simple payback7.1 years

Ignoring tax, financing changes and the time value of money, the additional annual cash flow recovers the Year 5 disadvantage in approximately 7.1 years—during Year 12.

What if the property is sold in Year 10?

By the end of Year 10, the refurbished case has generated approximately £8,529 less cumulative operating cash than doing nothing. If the works also add £20,000 to the Year 10 sale price, the additional proceeds after 2% selling costs would be £19,600.

£19,600 additional sale proceeds − £8,529 cash shortfall = £11,071 ahead before tax

That conclusion depends heavily on the assumed £20,000 sale-value uplift. If a buyer pays no premium for the works, the refurbishment remains behind at the Year 10 exit.

Inflation can help—or hurt

A rent uplift stated five years in advance should be separated from ordinary rental growth. Construction costs may also rise before the works begin. Model the refurbishment as a specific Year 5 adjustment, while applying different annual growth rates to rent and recurring costs.

The right refurbishment question

How much extra rent or sale value is needed—and by when—to recover the works cost and the rent lost while the property is empty?

Add a refurbishment to your forecast
About this example

The works cost, rental uplift and possible sale-value uplift are illustrative assumptions. Actual outcomes may differ.