How Parents Can Help Their Child Buy a Home Without Being on the Deeds: Joint Borrower Sole Proprietor Explained

What Is a Joint Borrower Sole Proprietor (JBSP) Mortgage?

A JBSP mortgage lets a parent (or another family member) go on the mortgage as a borrower, sharing legal responsibility for the monthly repayments, without going on the property's title. Your child is the sole owner. You are jointly liable for the debt.

Because the lender counts the parent's income alongside the child's when working out affordability, a JBSP arrangement can substantially increase what the household can borrow, without the parent's name appearing on the deeds at all.

This matters for two reasons: the parent is not treated as an owner of a second property, and inheritance and later-life planning around the parent's own home is not complicated by joint ownership of their child's.

How JBSP Differs From Adding Someone to Your Mortgage

It is worth being precise here, because the two are easily confused. Adding someone to an existing mortgage generally happens after completion: a partner moves in, a family member's name is added to an existing arrangement, and the property is usually already jointly owned or becomes so as part of that change.

JBSP is different in structure and timing. It is set up at the point of application, specifically so the parent's income boosts affordability while the property itself belongs to the child alone. If you are trying to work out which route fits your situation, the question to ask is whether you want joint ownership (adding someone to an existing mortgage) or joint liability without ownership (JBSP).

How JBSP Differs From a Guarantor Mortgage

A guarantor mortgage and a JBSP mortgage both involve a parent supporting a child's application, but the legal position is different. A guarantor typically agrees to cover repayments only if the borrower defaults, and is not usually assessed as a joint borrower for affordability in the same way. With JBSP, the parent is a full joint borrower from day one, jointly and severally liable for the whole mortgage, which is generally why lenders will count their income more fully towards what the household can borrow.

The Ownership and Tax Position for Parents

Because the parent is not on the title, JBSP is generally structured to avoid the parent being treated as an owner of a second residential property for the purposes of the additional stamp duty land tax surcharge that applies to buying while already owning a home. It can also mean the property does not form part of the parent's estate for future ownership purposes in the way that joint ownership would.

These are general principles rather than a substitute for advice on your own position, and stamp duty and inheritance tax treatment depend on individual circumstances, current legislation, and how the specific mortgage and any linked agreements are structured. Anyone considering JBSP should get advice on the tax position alongside the mortgage advice, not instead of it.

Which Lenders Offer JBSP?

Not every lender offers a Joint Borrower Sole Proprietor product, and the ones that do vary in how they treat the supporting parent's income, age limits for the parent, and how many years they will lend for. This is squarely a whole-of-market question: knowing which lenders offer JBSP at all, and which of those suit your family's specific ages, incomes and circumstances, is not something a single high-street branch can answer.

How JBSP Compares to a Gifted Deposit

A gifted deposit and a JBSP mortgage solve different problems, and many families end up using elements of both. A gifted deposit reduces the amount your child needs to borrow in the first place, which helps with loan-to-value and can unlock a better rate, but it does nothing for ongoing affordability if the mortgage still needs to be serviced from the child's income alone. JBSP does the opposite: it does not change the deposit, but it increases what the household is judged able to afford to repay each month, because the parent's income is added into the calculation.

Where a family can offer both a gifted deposit and JBSP support, the combination can meaningfully change what is achievable. Where only one is realistic, which one matters depends on whether the barrier is the deposit or the ongoing affordability calculation.

Is JBSP Right for Your Family?

JBSP suits families where the child's income alone falls short of what is needed to buy in the area they want, where the parent is comfortable being jointly and severally liable for the full mortgage (not just a portion of it), and where the parent does not want to become a joint owner of the property. It is less suited to families where the parent is close to retirement and may struggle to evidence continued income for the full mortgage term, or where the parent already has other significant borrowing that would affect their own position as a joint applicant.

FAQs

Which lenders offer Joint Borrower Sole Proprietor mortgages?

Availability changes regularly, and not all lenders offer JBSP as a product. A whole-of-market broker can check current live criteria against your family's ages and circumstances rather than relying on a single lender's rules.

Does the parent's name go on the property?

No. Under JBSP, the child (or children) is the sole owner on the title. The parent is a joint borrower on the mortgage, not an owner of the property.

Is the parent responsible for the whole mortgage, or just part of it?

Typically the whole mortgage. Joint borrowers under JBSP are usually jointly and severally liable, meaning the lender can pursue either party for the full amount if repayments are missed, not simply a proportional share.

Can we combine JBSP with a gifted deposit?

Yes, and many families do. A gifted deposit addresses the deposit and loan-to-value; JBSP addresses ongoing affordability. Used together they can open up options that neither would achieve alone.

Talk to Us Before You Decide

If your child's income does not quite stretch far enough on its own and you are considering how to help without becoming a joint owner, get advice before you commit to a structure. RM Mortgages serves families across Birmingham and the wider West Midlands, including Coventry, Wolverhampton, Walsall and Solihull, and we can talk you through whether JBSP, a gifted deposit, or a combination of the two fits your family's situation, alongside independent tax advice where it is needed.