Joint Mortgages Explained: How They Work, Who Can Apply, and What to Watch Out For
- Emma Patel - Personal Finance & Budgeting Specialist
- Apr 16
- 6 min read
Buying a home is one of the biggest financial commitments you’ll ever make — and for many people, the only way to get on the ladder is to buy with someone else.
A joint mortgage allows two or more people to combine their income and apply for a mortgage together. It can boost your borrowing power, help you buy sooner, and make homeownership more affordable — but it also comes with legal and financial risks if things go wrong.
In this comprehensive guide, we’ll explain exactly how joint mortgages work in the UK, who can apply, the key legal structures to understand, and the questions you need to ask before signing on the dotted line.
What Is a Joint Mortgage?
A joint mortgage is a mortgage taken out by two or more people together. Everyone named on the mortgage is jointly responsible for repaying the loan, even if they don’t all contribute equally to the deposit or repayments.
You can apply for a joint mortgage with:
A partner or spouse
A family member (e.g. parent, sibling, adult child)
A friend or flatmate
Up to three other people (some lenders allow up to four applicants)
Everyone’s income is considered, which can increase the amount you’re able to borrow.
How Does a Joint Mortgage Work?
When you apply for a joint mortgage, the lender will:
Assess each applicant’s income, credit score, and financial commitments
Combine the total income to determine how much they may lend
Require that all applicants are jointly and severally liable — meaning if one person can’t pay, the others are responsible for the full amount
You’ll also have to decide how to structure your ownership legally — either as joint tenants or tenants in common (explained below).
Who Can Get a Joint Mortgage?
You don’t have to be married or in a romantic relationship. Joint mortgages are common among:
Couples (married or unmarried)
Siblings
Friends buying together
Parents helping children get on the ladder
Lenders don’t care about your relationship — they care about affordability, creditworthiness, and whether the property is suitable security for the loan.
Types of Joint Ownership: Joint Tenants vs Tenants in Common
This is a crucial decision that affects your legal rights and what happens if one of you dies or wants to sell.
1. Joint Tenants
You both own the property equally (50/50)
If one of you dies, the other automatically inherits the property
You cannot pass on your share in a will
Common for married or long-term couples
2. Tenants in Common
You each own a specific share (can be 50/50, 70/30, etc.)
You can leave your share to someone in your will
More flexibility — ideal for friends, siblings, or those contributing unequal deposits
You’ll need a declaration of trust or cohabitation agreement drawn up by a solicitor to confirm who owns what.
Pros of Getting a Joint Mortgage
1. Higher Borrowing Power
Combining incomes usually increases the amount you can borrow compared to applying alone.
2. Shared Costs
Deposit, legal fees, mortgage repayments, and bills can be split — making homeownership more affordable.
3. Get on the Property Ladder Sooner
By pooling resources, you may be able to buy sooner than saving alone.
4. Suitable for Family Support
Parents can take out a mortgage jointly with their children to help them buy, without gifting cash.
Cons and Risks of Joint Mortgages
1. Shared Responsibility
Everyone is legally responsible for 100% of the debt — not just their share. If one person can’t or won’t pay, the other(s) must.
2. Credit Score Impact
If a co-borrower misses a payment, it affects everyone’s credit file.
3. Complex If You Split
If you fall out, break up, or one person wants to sell, untangling ownership can be difficult without prior legal agreements.
4. Tied Finances
You become “financially associated” with your co-applicants on your credit report, which can affect future borrowing.
How Much Can You Borrow with a Joint Mortgage?
Lenders usually offer up to 4 to 4.5 times your combined income — sometimes more for high-earning, low-risk applicants.
Example:
Applicant 1 income: £30,000
Applicant 2 income: £25,000
Combined: £55,000
Potential loan: £220,000 – £247,500 (depending on lender criteria)
Related article: How Much Deposit Do You Need for a Mortgage?
What Happens If One Person Wants Out?
Things change — relationships break down, people move abroad, or circumstances shift.
If one party wants to exit the mortgage:
The remaining borrower(s) must apply to remortgage in their own name
They must prove they can afford the mortgage alone
If approved, the departing party’s name is removed from the mortgage and title deeds
Legal fees and potential Stamp Duty may apply
If no one can afford it alone, you may need to sell the property.
Legal Protection: Why You Need a Declaration of Trust
A declaration of trust (or deed of trust) is a legal document stating:
How much each person contributed
How much equity each person owns
What happens if one person wants to sell, dies, or stops paying
Without this, disputes can become messy — particularly if you’re not joint tenants or haven’t contributed equally.
Tip: Always get independent legal advice, especially if buying with someone other than a spouse or civil partner.
Joint Mortgages and First-Time Buyer Status
Be careful — if one applicant has owned property before, it could affect:
Your eligibility for first-time buyer Stamp Duty relief
Access to Lifetime ISA bonuses
Participation in first-time buyer schemes
If both applicants are true first-time buyers, you can benefit from:
Stamp Duty exemption up to £425,000
Lifetime ISA use towards the deposit
Government schemes like the First Homes Scheme
Related article: First-Time Buyer Mortgage Guide
Unique Insight: Consider a Joint Borrower, Sole Proprietor Mortgage
This little-known option allows:
A parent (or someone else) to be on the mortgage but not on the deeds
Their income is used to support the loan
The child or main buyer retains full legal ownership
It protects parents from second home taxes and simplifies inheritance — but not all lenders offer it.
Speak to a mortgage broker if you're considering this route.
Related article: Should You Use a Mortgage Broker?
FAQs: Joint Mortgages in the UK
Can I get a joint mortgage with a friend?
Yes — friends can apply together, but you should agree on how ownership is split and have a legal document (declaration of trust) in place.
Do we both need to have good credit?
Ideally, yes. Lenders will check both credit files, and a poor score on one side could affect your eligibility or interest rate.
Can one person pay a bigger deposit?
Yes — especially with tenants in common. You can legally agree to unequal shares of ownership, but this must be recorded formally.
What happens if we split up?
You’ll need to agree on:
Who stays in the property
Whether the property will be sold
How equity is divided
Legal advice and a cohabitation agreement can help avoid disputes.
Can we add or remove someone from a joint mortgage later?
Yes — through a remortgage or transfer of equity, subject to affordability checks and lender approval.
Final Thoughts: Is a Joint Mortgage Right for You?
Joint mortgages can open the door to buying a home sooner, especially in expensive areas or for those on modest incomes. But they also come with shared legal and financial responsibility — and that means you must choose your co-borrowers carefully.
Whether you're buying with a partner, sibling, or friend, it’s essential to:
Understand your legal structure (joint tenants vs tenants in common)
Agree in writing how ownership and repayments will work
Protect yourself with the right legal agreements
For anything outside the norm — especially where income, ownership shares, or relationships are unequal — speak to a solicitor and a mortgage broker before proceeding.
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