The manoeuvre and why it's awkward
Two households selling two homes to buy one shared property is the cleanest version of multigenerational living on paper: everyone arrives with equity, ownership shares are set by contribution, no one is a guest in the other's house. In practice it's a three-way timing problem — two sales and one purchase that all want to happen at once, in a market that doesn't care about your plans.
Count the transaction costs first
Three transactions means three sets of fees. Between agent/estate-agent fees on two sales, legal fees on all three transactions, property transfer taxes on the purchase, surveys and moving costs, total friction commonly lands between $30,000–$80,000 / £20,000–£60,000 depending on prices and jurisdiction. This number belongs in the model before anyone falls in love with a listing — it's the price of admission, and it only pays back over years of shared running costs.
The three sequencing options
Sell both first, rent briefly, buy together
The safest and least popular option. Both households become cash buyers — the strongest position to purchase from — and nobody's purchase depends on a chain of strangers. The costs are a few months of rent, a second move, and the psychological difficulty of being briefly homeless-on-paper. Families consistently overweight those costs and underweight the negotiating power.
Sell one, keep one as the base
One household sells and moves into the other's home temporarily; that combined household then sells and buys. This tests day-to-day compatibility before the irreversible step — genuinely valuable — but the household whose home is the base holds all the practical power in the interim, and the arrangement needs an explicit time limit or it drifts.
Buy first with a bridge, sell after
Bridging finance or a bridge loan lets you secure the new home before selling. It's the most expensive option — bridging interest commonly runs far above mortgage rates — and it converts a timing problem into a debt problem if either sale is slow. Appropriate mainly when the target property is genuinely rare.
Decisions to make before listing anything
- Shares by contribution, documented. If contributions are unequal, own as tenants in common in the actual proportions, with a co-ownership agreement signed before completion — not after moving in.
- What if one home sells and the other doesn't? Agree the fallback in advance: price cuts, delay, or the unsold home converting to a rental with its equity entering later.
- Whose name is on any mortgage. If borrowing is needed to bridge the gap, that's the multigenerational mortgage question — read it before choosing a structure.