Final Staircasing to 100%: Full Ownership SDLT
SDLT on the final share purchase to reach full ownership, the leasehold transition, and what changes once you own 100%.
Key Takeaways
- Under the default pay-in-stages option, the transaction that takes you to 100% takes you over the 80% line, so it is a linked-transactions calculation on the cumulative consideration actually paid for all staircased shares, not on current market value
- If you made the market value election at your initial purchase, no SDLT is ever due on the final staircase, regardless of the price you pay for the remaining share
- The final share price is based on a RICS valuation of the full property at the time of the final staircase, and that price is added into the cumulative staircased consideration for the SDLT linked calculation
- Transitioning from leasehold to freehold is a separate process from reaching 100% equity ownership
- Losing housing association protections on rent and service charges after 100% ownership is a real financial consideration
- The 5% additional dwelling surcharge could apply if you own another residential property when you staircase to 100%
- Going directly from a sub-80% share to 100% in one transaction keeps the SDLT calculation to a single linked-transaction filing
- Your mortgage lender must be notified of and consent to the final staircasing transaction before it can complete
In this article
What Is Final Staircasing?
Final staircasing is the transaction in which you buy the remaining share of your shared ownership property to reach 100% ownership. Whether you are buying the last 5% or jumping directly from 40% to 100% in one go, the transaction that takes you to full ownership is the final staircase.
This is a significant milestone. After final staircasing you are an outright owner of your home, with no ongoing rent obligation to the housing association for the portion you did not previously own. The mechanics of the transaction are similar to intermediate staircasing, but with additional legal steps because full ownership changes the structure of your property title.
For context on how SDLT applies to earlier staircase purchases before the final one, see the staircasing stamp duty guide. If you made a market value election at your initial share purchase, no SDLT applies to any staircasing transaction, including this final one.
Calculation Method
For a final staircase under the pay-in-stages option, the SDLT calculation adds the price of the final share to the consideration paid for any earlier staircasing tranches (after the initial share premium), then applies standard SDLT rate bands to that cumulative figure. Any SDLT already paid on the earlier linked staircasing purchases is credited against the result.
Example 1: you bought a 75% initial share and have never staircased before. Now you buy the remaining 25% for £100,000 (25% of a £400,000 property). This is the only linked staircasing transaction. SDLT is calculated on £100,000 using standard rates: 0% on £100,000 = £0. No earlier staircasing SDLT to credit. SDLT due: £0.
Example 2: you bought a 40% initial share. You have since staircased in tranches up to 75%, paying a total of £140,000 for those tranches, with no SDLT due at the time (because you stayed below 80%). You now buy the final 25% for £150,000, crossing 80% and reaching 100%. Total linked staircased consideration: £140,000 + £150,000 = £290,000. SDLT: 0% on £125,000 + 2% on £125,000 + 5% on £40,000 = £4,500. Less previously paid staircasing SDLT: £0. SDLT due at the final staircase: £4,500.
Leasehold to Freehold Transition
A common misconception is that buying 100% of your shared ownership property automatically means you own the freehold. This is not the case. In shared ownership, you hold a leasehold interest in the property from the outset. Reaching 100% equity means you own all of the lease, but the freehold remains with the housing association or freeholder.
Acquiring the freehold is a separate process called leasehold enfranchisement. For houses, you have a statutory right to buy the freehold under the Leasehold Reform Act. For flats, individual flat owners must usually act collectively with other leaseholders to enfranchise. The right to buy your freehold is governed by the terms of your lease and the relevant legislation, and involves a separate purchase and its own SDLT calculation.
Some shared ownership housing associations will offer the freehold at the same time as the final staircase, but this is not automatic. If freehold enfranchisement is available, the premium paid for the freehold is a separate chargeable consideration, and SDLT is calculated on that premium in addition to the SDLT on the final leasehold share.
Check Your Lease Terms
Your shared ownership lease sets out the terms under which you can acquire the freehold, if at all. Review these terms with your solicitor before proceeding with the final staircase to understand your full path to outright ownership.
Losing Housing Association Protections
Shared ownership comes with certain protections for the shared owner provided by the housing association. These include regulated rent increases on the unowned share (typically RPI-linked), support with major maintenance issues, and in some cases housing management services.
Once you reach 100% equity ownership, the rent obligation to the housing association ceases, which is the main financial benefit of staircasing fully. However, if you remain on a leasehold title, you may still be subject to service charges and ground rent as set out in the lease, and these protections are governed by leasehold legislation rather than housing association policy.
Service charges on leasehold properties can increase significantly once the housing association is no longer involved in managing your ownership. Understanding the future service charge implications is essential financial planning before committing to final staircasing.
Mortgage Considerations
Final staircasing requires your mortgage to be renegotiated or extended to cover the full purchase price of the remaining share. Your existing shared ownership mortgage will be secured against only your current share. To complete the final staircase, you need a mortgage that covers the new purchase or sufficient savings to buy the final share outright.
Most buyers either extend their existing mortgage with the same lender or remortgage with a new lender to release the funds needed for the final share. The new mortgage is secured against the full property value (not just your share) as you will be the sole owner. Mortgage capacity must be assessed by a mortgage broker or advisor before proceeding.
The housing association will confirm in writing that they consent to the final staircasing once a RICS valuation has been carried out. Your solicitor coordinates the mortgage completion and the staircasing completion to occur simultaneously, ensuring funds are transferred and the title is updated on the same day.
Additional Dwelling Surcharge Considerations
The 5% additional dwelling surcharge applies to residential property purchases by buyers who already own at least one other residential property on completion (the surcharge rose from 3% to 5% in October 2024). If you own a buy-to-let property or a second home in addition to your shared ownership home, the surcharge could apply to the linked cumulative consideration that is used to compute SDLT on the final staircase.
Example: cumulative linked staircased consideration of £253,000 (as in the worked example above) attracts a 5% surcharge of £12,650 on top of the standard SDLT. This can make a material difference to the cost of final staircasing for those with additional properties.
If the shared ownership property being staircased to 100% is your only residence and you sell any other residential property within three years of completing the final staircase, you can apply for a refund of the ADS. This refund process requires a formal claim to HMRC within the three-year window.
Worked Example: Owning 75%, Buying Remaining 25%
Scenario Details
- Initial share: 40% (no market value election)
- Intermediate staircasing: 35% bought in tranches, total consideration £115,500, no SDLT or returns required (stayed at 75% or below)
- Current ownership just before final staircase: 75%
- Final share to purchase: 25%
- Current RICS market valuation: £350,000
- Final share consideration: 25% of £350,000 = £87,500
- Buyer status: Standard (not FTB, no other properties)
SDLT Calculation (Linked Transactions)
| Prior staircased consideration (35% in tranches) | £115,500 |
| Final staircase consideration (25% of £350,000) | £87,500 |
| Total linked staircased consideration | £203,000 |
| SDLT: 0% on £125,000 | £0 |
| SDLT: 2% on £78,000 (£125,001–£203,000) | £1,560 |
| Less: SDLT already paid on prior linked staircasing | (£0) |
| SDLT payable on the final staircase | £1,560 |
Same Scenario with £550,000 Current Market Value
| Prior staircased consideration (35% in tranches) | £115,500 |
| Final staircase consideration (25% of £550,000) | £137,500 |
| Total linked staircased consideration | £253,000 |
| SDLT: 0% on £125,000 | £0 |
| SDLT: 2% on £125,000 | £2,500 |
| SDLT: 5% on £3,000 (£250,001–£253,000) | £150 |
| SDLT payable on the final staircase | £2,650 |
With Additional Dwelling Surcharge (owner of another property)
| Total linked staircased consideration | £253,000 |
| Standard SDLT (as above) | £2,650 |
| 5% additional rate surcharge on £253,000 | £12,650 |
| Total SDLT with surcharge | £15,300 |
This illustrates how significantly the additional dwelling surcharge affects the cost of final staircasing for buyers who own additional properties. The SDLT is computed on the cumulative consideration paid for the staircased shares, not on the current market value of the property as a whole. Use the final staircasing stamp duty calculator to run the numbers for your own scenario.
Timing Your Final Staircase
The timing of your final staircase affects both the price you pay and the SDLT you owe. Property value growth increases the consideration and therefore any SDLT due. If you believe property values in your area will rise significantly, completing the final staircase sooner locks in a lower price and SDLT basis.
Conversely, if your financial situation means you cannot yet afford the final share, there is no deadline by which you must staircase. The housing association lease will include a staircasing right for the duration of the lease, so there is no fixed window. You staircase when it is right for you financially.
If you are selling another property around the same time as final staircasing, timing the sale to complete before the staircase can avoid the additional dwelling surcharge, or at minimum creates the conditions for an ADS refund claim later.
Legal Process for Final Staircasing
The legal process for final staircasing involves several steps:
- Instruct a solicitor and notify your mortgage lender. Your solicitor coordinates with the housing association and your lender simultaneously.
- Commission a RICS valuation of the property to establish the current market value for the share price and SDLT basis.
- Receive the housing association's staircasing memorandum setting out the price for the final share and confirming their consent.
- Arrange mortgage finance for the final share if not buying with savings. Your lender will carry out their own valuation.
- Exchange of contracts between you and the housing association (or in some cases a deed of variation to the lease).
- Completion: funds transfer, lease surrendered or amended, SDLT return filed within 14 days.
- Land Registry update to reflect 100% ownership on the title. Your SDLT certificate is required for this.
After You Own 100%
Once the final staircase completes and the title is updated, you are the full equity owner of your home. Your rights and obligations change immediately: there is no more rent to the housing association, you cannot be asked to sell back to the housing association, and you can sell on the open market without restriction.
If you later sell the property, the full sale proceeds are yours. SDLT rules that apply to you as a future seller are the same as for any standard property sale. See the standard purchase guide for how SDLT works from a buyer's perspective on a conventional sale.
The shared ownership journey from initial purchase through to 100% ownership can involve multiple SDLT events. For a comprehensive overview of every touchpoint, revisit the shared ownership complete guide.
Frequently Asked Questions
How is stamp duty calculated when I staircase to 100%?
Under the default pay-in-stages option, the transaction that reaches 100% crosses the 80% line and is a linked transaction with any earlier staircasing purchases you made after your initial share. SDLT is calculated on the cumulative consideration paid for all those linked staircased shares, using standard rates (0% up to £125,000, 2% on £125,001 to £250,000, 5% on £250,001 to £925,000). Any SDLT already paid on earlier linked staircasing transactions is credited. If you made the market value election at initial purchase, no SDLT is due on the final staircase.
Do I get the freehold when I staircase to 100%?
Not automatically. Reaching 100% equity means you own all of the lease, but the freehold may remain with the housing association. For houses, you may have a statutory right to buy the freehold separately under leasehold reform legislation. For flats, freehold enfranchisement usually requires collective action with other leaseholders. Your solicitor can advise on your specific freehold rights.
Can the additional dwelling surcharge apply to final staircasing?
Yes. If you own another residential property on the completion date of the final staircase, the 5% additional property surcharge applies to the linked cumulative consideration used to calculate SDLT. If the staircased property becomes your main residence and you sell any other property within three years, you can claim a refund of the surcharge from HMRC.
Do I need to remortgage when I staircase to 100%?
In most cases yes, unless you can fund the final share from savings. Your existing shared ownership mortgage needs to be extended or replaced to cover the new total mortgage value on full ownership. Your mortgage lender must also formally consent to the staircasing transaction. A mortgage broker or advisor can guide you through the options.
Can I jump directly to 100% from a low share like 40%?
Yes. You can staircase directly from any current percentage to 100% in a single transaction. That transaction crosses 80% and is treated as linked with any earlier staircasing purchases. SDLT is calculated on the cumulative consideration of those linked share purchases. If you had never staircased before, that cumulative amount is simply the price of the final share itself. If the market value election was made at initial purchase, no SDLT is due.
Reviewed by
Emma Richardson, MRICS
Chartered Surveyor & Property Tax Specialist
Emma Richardson is a RICS-qualified Chartered Surveyor with over 12 years of experience in UK property taxation. She founded Calculate My Stamp Duty UK to help buyers understand the complex world of property transaction taxes.