Family 8 min read
Co-buying with family: parents, siblings and the bank of mum and dad
Buying with family can open doors that solo buyers can't reach. It can also blur money, love and power in ways that are hard to unpick. Here's how to keep help helpful — and relationships intact.
Family help changes the maths — and the relationship
A parent topping up a deposit, a sibling pooling savings, or a grandparent acting as guarantor can be the difference between buying and waiting. But family money rarely arrives without strings, even when nobody says so out loud.
The key is to separate three things: the gift or loan, the ownership of the property, and who gets to live there. Mix them up and a small misunderstanding can become a lasting resentment.
Start every family arrangement with the same question you would ask a stranger: what happens if someone wants out, can't pay, or dies?
Gifted deposit
- •Parent gives money towards the deposit
- •Usually needs a letter saying it's not a loan
- •Can affect mortgage affordability checks
- •Inheritance-tax rules may apply
Loan from family
- •Money is repaid, often on sale
- •Should be documented with interest and terms
- •Lender may treat it as a debt
- •Can complicate the mortgage application
Family as co-owner
- •Parent or sibling is on the title and mortgage
- •Ownership share should match contribution
- •Lives there or invests — decide up front
- •Needs a Deed of Trust like any other co-buyer
Gift or loan? Write it down either way
Mortgage lenders usually want a letter confirming that gifted money is not repayable. If it is a loan, the lender needs to know, because it changes how much you can borrow.
Even a gift should be discussed. Does the giver expect a say in the property? Will they feel entitled to visit or comment on decisions? A conversation now avoids a silent assumption later.
For loans, document the interest rate, repayment trigger and what happens if the property is sold at a loss. Treat it at least as formally as you would a loan from a bank.
Tap a card to flip it over.
Siblings: equal doesn't always mean fair
Brothers and sisters can make brilliant co-buyers. They often share values, trust and long-term goals. They also share a lifetime of family dynamics that can resurface under pressure.
The biggest trap is assuming fairness means equality. If one sibling puts in £60,000 and the other puts in £20,000, equal ownership is not fair. A Deed of Trust should record the real split.
Also think about partners. A sibling's boyfriend or girlfriend moving in changes the household. So does one sibling wanting to let a room. Write the rules before you need them.
- 1
Document contributions
Deposits, fees, renovations and monthly payments all need to be recorded.
- 2
Agree exit terms
What if one sibling wants to buy the other out, or bring in a partner?
- 3
Plan for life changes
Marriage, children, moving away — each can force a sale if not planned for.
- 4
Involve partners carefully
Decide whether partners get a say, and after how many nights they contribute.
- 5
Review yearly
A quick check-in keeps small resentments from becoming big arguments.
Parents as co-owners: power and inheritance
When a parent goes on the mortgage and title, they become a legal owner. That gives them real power over selling, remortgaging and who inherits their share.
It also affects stamp duty, capital gains tax and inheritance tax. A parent who already owns a home may pay the second-home surcharge. If the property isn't their main residence, they may face capital gains tax on their share of any increase in value.
Think about the long term. If a parent dies, their share goes to whoever their will names — which might not be the child living in the house. A Deed of Trust and a clear will are essential.
Informal help from parents or family towards a deposit or purchase.
Money given with no expectation of repayment, usually confirmed in writing for the lender.
Extra stamp duty when someone who already owns a home buys another.
Tax on profit when selling an asset that isn't your main home.
Tax on money or property passed on after death, above certain thresholds.
A parent promises to pay if the buyer defaults, without owning the property.
Keep the relationship bigger than the deal
The best family co-buying arrangements are boring on paper and warm in person. That only happens when everyone feels the deal is fair, documented and revisable.
Have the hard conversations early: what happens if someone can't pay, wants out, gets married, or needs care. Put the answers in a Deed of Trust and a Co-ownership Agreement.
Then review them. Family circumstances change faster than friendships. A yearly check-in, however brief, keeps the arrangement honest and the relationship intact.
Talk this through with the community
Nothing here is advice for your situation. Bring your questions to other locked-out buyers working through the same decisions.
Join the discussion →
Questions & experiences
Ask a question about this article or share how it played out for you. Comments are public and moderated.
Loading comments…