How does staircasing work with shared ownership and what does it cost?

Staircasing is buying more of your shared-ownership home from the landlord in tranches. Under the 2021 new-model lease you can buy 1% a year at reduced fees, while older leases normally require 10% chunks. Each staircase costs roughly £1,500–£3,500 — a RICS valuation (£400–£600), solicitor fees (£800–£1,500), possible SDLT and a mortgage variation — and every step needs a fresh valuation.

What “staircasing” actually means

When you buy a shared-ownership home you purchase between 10% and 75% of the equity (5% on some Affordable Homes Programme 2021–2026 homes) and pay rent on the rest to the housing association. Staircasing is the formal process of buying additional equity slices at the property’s current market value. Each slice reduces your rent proportionally, and if you reach 100% you own the home outright — on a house you usually also get the freehold, on a flat you keep a long leasehold.

There are two regimes running in parallel in April 2026:

Old-model leases (pre-April 2021): minimum tranche 10%, maximum three staircases in some leases, typical full costs £2,000–£3,500 per step.
New-model leases (AHP 2021–2026 and SAHP 2026–2036): minimum tranche 1% a year for the first 15 years with capped landlord admin fees, plus a 10-year landlord warranty on essential repairs.

Check your lease or your welcome pack before you plan a staircase — landlords will tell you which model you are on, but it is written in the lease.

The cost stack on a single staircase

The headline cost is the extra equity itself, priced at today’s market value — not what you originally paid. On top, you pay fees that stay broadly the same whether you are buying 1% or 25%.

Cost item	Typical 2026 range	Notes
RICS “red-book” valuation	£400 – £600	Valid 3 months; commissioned through the landlord’s panel
Landlord admin fee	£200 – £500 (new model); £500 – £1,200 (old model)	1% staircases are capped lower under AHP 2021
Your solicitor	£800 – £1,500	Needed to vary the lease and register with HM Land Registry
Mortgage variation / new product	£0 – £1,000	Some lenders charge a product fee; others waive it
SDLT on the new share	0 – several thousand	Depends on the election you made at first purchase (see below)
HM Land Registry fee	£20 – £135	Scales with the staircase value

A single 10% staircase on a £300,000 flat where you already own 40% typically costs £1,800–£3,200 in fees on top of the £30,000 equity. A 1% new-model staircase on the same flat is usually £800–£1,500 in fees — still meaningful, which is why many owners batch them.

Architectural details of a shared-ownership apartment block — New-model 2021 leases allow 1% annual staircasing with capped landlord fees.

Stamp duty: the one-off election vs per-staircase route

This is where people get a nasty surprise five years after purchase. At first purchase of a shared-ownership home you choose one of two SDLT routes:

Market-value election. You pay SDLT on the full 100% market value up front, even if you only bought 40%. Future staircases are then SDLT-free — a big win if you plan to staircase repeatedly.
Staged route. You pay SDLT only on the share you buy. Future staircases may attract SDLT — but only once your cumulative ownership passes 80%. Below 80%, no SDLT on the staircase itself.

First-time buyers are often better off with the staged route thanks to FTB SDLT relief on the first purchase. Existing owners who have already staircased past 80% should expect SDLT on each subsequent step. Our stamp duty calculator lets you model both options.

Worked example — 10% staircase in April 2026

You bought a 40% share of a £250,000 flat in 2022. The flat is now valued at £275,000. You want to move to 50%.

Extra 10% equity at today’s value: £27,500
RICS valuation: £500
Landlord admin fee: £350 (new-model AHP)
Solicitor: £1,100
Mortgage variation (product fee absorbed): £0
Land Registry: £45
SDLT: £0 (you elected the staged route, you’re below 80%)
Total outlay: £29,495, and your rent drops proportionally — on a 2.75% rent rate that saves roughly £63 a month.

The payback on the fees alone is around 32 months; everything after that is ahead of where you’d be staying at 40%.

When not to staircase

Rates have spiked and you’d be remortgaging the extra share at a much higher rate than your current fix — check the remortgage vs product transfer guide.
You are planning to move within 18 months — fees rarely pay back that quickly.
Your service charge is rising faster than your rent — staircasing doesn’t touch service charge, so you are buying a bigger slice of a building with a growing cost base. See how shared-ownership rent and service charges rise.

Common misconception: “Each staircase buys back at my original price”

No. Every staircase is priced at the current RICS valuation, which usually means you pay more per percent than you did on day one. If the property has fallen in value, you pay less — but in a rising market, delaying is more expensive. That’s why many buyers on new-model leases plan their 1% staircases as a standing order rather than waiting.

This is information, not regulated mortgage or tax advice. Your housing association will send a formal offer letter once the RICS valuation is in — review it with your solicitor before signing.