Exit planning: what happens when one co-buyer wants out

Over a 25-year mortgage, the odds that four people all stay put are close to zero. Exit planning is not pessimism, it is the thing that lets everyone commit with confidence.

The goal is a process everyone agreed to when they liked each other, so that nobody has to negotiate it in a moment of stress.

Notice: the leaver gives written notice, typically three to six months. A minimum ownership period of one to two years before notice can be served is common and stops impulsive exits.

Valuation: an agreed RICS-based mechanism produces a market figure. The leaver's entitlement is their share of the equity, not their share of the sale price, so the outstanding mortgage comes off first.

First refusal: the remaining owners get an exclusive window, usually 60 to 90 days, to buy the leaver's share.

Replacement or sale: if they cannot, the group may bring in a replacement co-buyer acceptable to all owners and the lender, or the property is sold and proceeds distributed by share.

A buyout usually means a transfer of equity and a fresh affordability assessment. The remaining owners must qualify for the whole mortgage on their own. If they cannot, the buyout fails no matter what your deed says.

Build this into the plan: state explicitly what happens when a buyout is affordability-blocked, and cap how long the group must keep trying before a sale is triggered.

Include a clear list of events that allow any owner to force a sale: sustained arrears, bankruptcy, a breach of the deed, or simply the expiry of the buyout window. Without one, an owner can be trapped indefinitely.

Add a dispute route as well: negotiation, then mediation, then, as a last resort, an application under the Trusts of Land and Appointment of Trustees Act 1996. Naming mediation first keeps most disagreements out of court.