Lease Extension Valuations — What Surveyors Actually Assess

What Does a Lease Extension Valuation Actually Involve?

When you instruct a RICS surveyor to value your lease extension premium, they are not simply multiplying your flat's value by a percentage. They are assessing what the freeholder loses by granting you a longer lease at a peppercorn ground rent — a loss that has two main components: the lost ground rent income and the deferred reversion value.

Component 1 — Ground Rent Capitalisation

Your lease probably requires you to pay a ground rent to the freeholder. When you extend your lease, this ground rent is reduced to a peppercorn (effectively zero) for the remainder of the new 990-year term. The freeholder therefore loses that income stream.

Ground rent capitalisation converts this future income into a present-day lump sum. The formula is:

> **Capitalised value = Annual ground rent ÷ Capitalisation rate**

For example, a ground rent of £300 per year capitalised at a 5% rate gives a capitalised value of £6,000. The capitalisation rate reflects the investment return the freeholder could achieve on the premium received, and is typically in the range of 4–6% depending on the circumstances. Your surveyor and the freeholder's surveyor will often dispute this rate.

Component 2 — The Reversion Value

At the end of your existing lease term, the property would ordinarily revert to the freeholder. By extending the lease to 990 years, you are effectively deferring the freeholder's right to take back the property by nearly a millennium — for practical purposes, indefinitely.

The reversion value is calculated by taking the current market value of the property and discounting it back over the remaining lease term at the **deferment rate**:

> **Reversion value = Current property value × (1 / (1 + deferment rate)^years remaining)**

A lower deferment rate produces a higher reversion value (and a higher premium). RICS guidance historically pointed to approximately 4.75% for flats and 5% for houses, but these figures are regularly contested at the First-tier Tribunal and vary with market conditions.

Worked Example

A flat worth £380,000 in the open market, with 78 years remaining on the lease and a £250 per year ground rent:

• **Ground rent capitalisation:** £250 ÷ 5% = £5,000
• **Reversion value:** £380,000 × (1 / (1.0475)^78) = approximately £10,400
• **Marriage value:** £0 (abolished under the Leasehold and Freehold Reform Act 2024)
• **Estimated premium: approximately £15,000 – £18,000** (before professional fees)

This is a simplified illustration. Surveyors also consider comparables, lease terms, service charge history, and the condition of the building.

Why the Two Surveyors Often Disagree

The freeholder's surveyor and your surveyor will typically argue about:

• The open market value of the flat (the higher the value, the higher the premium)
• The deferment rate (each 0.25% change can move the premium by thousands)
• The capitalisation rate for the ground rent
• The relevance of comparable tribunal decisions

This is why most cases settle through negotiation — both parties have incentives to avoid tribunal costs.

First-tier Tribunal

If the parties cannot agree, the First-tier Tribunal (Property Chamber) determines the premium. Tribunal decisions are publicly available and form a body of case law that informs future valuations.

Getting an Estimate

Before spending money on professional fees, our [Lease Extension Calculator](/lease-extension-calculator) allows you to input your property value, ground rent, remaining term, and rate assumptions to produce an indicative premium range. Use it as a starting point before instructing a surveyor.