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Understanding Shared Ownership

A guide to buying a share of a property and how shared ownership mortgages work in the UK.

What is Shared Ownership?

Shared ownership is a government-backed scheme designed to help people buy a home when they can't afford to purchase one outright on the open market. It's particularly popular with first-time buyers.

With shared ownership, you buy a share (typically between 10% and 75%) of the property's value and pay rent on the remaining share owned by a housing association. This makes the deposit and mortgage more affordable whilst you're still building equity in your home.

Kumberi includes a standalone shared ownership calculator (mortgage on your share, rent on the unsold share, and staircasing). It is not yet part of a full year-by-year life scenario, which still treats a home as 100% owned.

How Shared Ownership Works

The Three Components

1. Your Share

You purchase a share (e.g., 25%, 50%, 75%) with a mortgage and deposit. Typical minimum share is 10%, maximum 75%.

2. Rent on the unsold share

You pay monthly rent on the share you do not own (held by the landlord, usually a housing association). The rate is set in your lease and varies by provider — many schemes use an illustrative figure around 2.75% of that share per year.

3. Service Charges

Monthly service charges cover building maintenance, insurance, and management (typically £100-£200/month).

Example Monthly Costs

Property value: £400,000Your 25% share: £100,000
10% deposit:£10,000
Mortgage (25 years at 4.5%):£500/month
Rent (2.75% on £300,000):£688/month
Service charge:£150/month
Total monthly cost:£1,338/month

* Example for illustration only. Your actual costs will vary based on property value, share percentage, mortgage rate, and location.

Staircasing: Increasing Your Share

Staircasing is the process of buying additional shares in your property over time. Minimum and maximum steps depend on your lease and landlord; you can usually build towards 100% ownership, at which point you own the property outright and no longer pay rent on the unsold share.

How Staircasing Works:

  • Property valuation: A RICS surveyor values the property at current market rates (typically £300-£500)
  • Purchase additional share: You buy the additional percentage based on the new valuation
  • Reduced rent: Your monthly rent decreases proportionally to the share you now own
  • Legal fees: Budget £1,000-£2,000 for conveyancing and legal work

Staircasing with Remortgaging

If property values have increased, you may be able to remortgage to release equity and fund staircasing without additional cash. Our calculator can model this scenario.

Example Staircasing Journey:

Year 1: Own 25% | Property value £400,000
Rent: £688/month
Year 5: Buy 25% more (value now £450,000)
Rent: £516/month
Year 10: Buy final 50% (value now £500,000)
Own 100% - No rent!

Benefits and Considerations

Benefits

  • ✓Smaller deposit required (5-10% of your share)
  • ✓Smaller mortgage needed than buying outright
  • ✓Build equity as property values rise
  • ✓Can increase your share through staircasing
  • ✓New-build properties often in good locations
  • ✓Stamp duty may be payable in stages on shared ownership purchases; first-time buyer relief can apply depending on value and how you elect to pay (see GOV.UK)

Important Considerations

  • !Monthly costs include mortgage, rent, and service charges
  • !Rent and service charges typically increase annually
  • !Staircasing costs based on current market value, not original price
  • !Resale restrictions may apply (typically can only sell to eligible buyers)
  • !Alterations require housing association permission
  • !Less choice of properties compared to open market

Who Can Apply?

Shared ownership is designed for people who cannot afford to buy a suitable home on the open market. Eligibility criteria typically include:

  • Household income of £80,000 or less (£90,000 in London)
  • First-time buyer or previous homeowner who can't afford to buy now
  • Able to demonstrate you can afford the monthly costs
  • Not already own another property (with some exceptions)

Using Kumberi's Shared Ownership Calculator

Our calculator helps you model the full lifecycle of a shared ownership purchase:

Initial Purchase

Enter property value, your initial share percentage, deposit, and mortgage details to see your monthly costs.

Plan Staircasing

Model purchasing additional shares over time, including property appreciation and associated costs.

Remortgaging Strategy

See how remortgaging to release equity can help fund staircasing without additional cash savings.

Long-term Projections

Visualise your journey to 100% ownership with detailed projections of costs, equity, and timeline.

Further Resources