Springboard mortgages: what the parent really risks (2026)
More than half of the homes sold in England and Wales last year changed hands for £300,000 or less — 477,484 of 879,402 registered transactions, or 54.3% (HM Land Registry price paid, 2025). Yet at the Bank of England's most recent quoted 75% loan-to-value five-year fixed rate of 4.32% (April 2026), a 10% deposit on a £250,000 home still means finding £25,000 in cash. For many first-time buyers, that deposit — not the monthly payment — is the wall.
Security-backed family mortgages are built to get around that wall. Marketed under names such as "springboard", "family deposit", "family boost" or "family offset", they let a parent or close relative put up the deposit's worth of security — without handing over the cash as a gift, and without going on the property's title. The borrower can then borrow up to 100% of the price.
The borrower's side of this is well covered. What gets two sentences in most guides is the relative's side: where their money actually sits, what it earns, when it comes back, and what happens to it if the payments stop. This piece walks through that structurally — not as advice.
Two structures, two very different risks
There are broadly two ways a relative can stand behind the loan. They are not the same, and the difference matters enormously to the relative.
| Savings-as-security | Charge over the parent's home | |
|---|---|---|
| What is pledged | Cash, locked in a lender-held account (typically 5–10% of the price) | A legal (second) charge over the parent's own property |
| Who owns it | The parent keeps ownership of the cash | The parent keeps the home; the lender registers a charge |
| At risk on default | The locked savings | A capped share of the parent's home equity |
| Worst case | The parent loses some or all of the locked cash | The charge is enforced against the parent's property |
| On the property title? | No | No |
In the savings route, the relative deposits a sum — commonly 10% of the purchase price — into an account held by the lender. On a £250,000 purchase that is £25,000. The relative still owns the money; it simply cannot be touched while it is acting as security.
| Purchase price | Security at 5% | Security at 10% |
|---|---|---|
| £200,000 | £10,000 | £20,000 |
| £250,000 | £12,500 | £25,000 |
| £300,000 | £15,000 | £30,000 |
In the charge route, no cash moves. Instead the lender registers a charge over the relative's own home, so that equity — rather than savings — backs the shortfall if things go wrong. That is the structure behind the search phrase "guarantor mortgage, parent's house at risk".
Where the money sits, and what it earns
In a savings-backed product the cash is held in a linked account, usually in the relative's name, for a fixed period. It typically earns interest — but the rate is set by the lender, and is frequently below what the same money could earn in an equivalent fixed-term savings account on the open market (Bank of England, quoted household deposit rates).
That gap is the real, recurring cost of helping. Every percentage point of difference on £25,000 is £250 a year. Over a five-year lock, a two-point gap is roughly £2,500 in forgone interest (illustrative, on a simple-interest basis) — on top of having the capital frozen and inaccessible for the term.
What happens if the payments stop
This is the part the marketing tends to soften. If the borrower falls into arrears and the loan is not recovered, the lender looks to the security.
- Savings route: the locked savings are the lender's recourse. In many structures the lender sells the property and then takes any shortfall from the relative's savings; in others the savings can be drawn on more directly. Either way the relative's capital is genuinely exposed — this is security, not a symbolic gesture.
- Charge route: the lender can enforce the charge against the relative's home. The amount is usually capped at the charged percentage, but in the worst case it draws the relative's own property into the recovery.
Because the relative's money or home is on the line, lenders generally require the security provider to take independent legal advice before signing — a practice rooted in how the courts treat third-party guarantees. The point of that advice is to make sure the relative understands they are a creditor's security, not a bystander. Mortgages of this kind are regulated, and the borrower's affordability is assessed by the lender under the Financial Conduct Authority's mortgage conduct rules (FCA MCOB).
When the security is released
The lock is not forever. Release usually turns on one — or a combination — of three triggers:
| Trigger | How it works |
|---|---|
| Fixed period | Savings or charge released after a set term, commonly three to five years, provided payments have been kept up |
| LTV threshold | Security released once the mortgage falls below a set loan-to-value (for example 80%) through repayment and any rise in the property's value |
| Payment record | Release is conditional on a clean payment history over the period |
On release, the relative gets their capital back — with any interest the account has accrued in the savings route, or a discharge of the charge in the home route. Whether the LTV trigger is met on time depends partly on house prices, which no one can promise: the UK House Price Index moves month to month (ONS UK HPI), and a flat or falling market can leave a loan above the release threshold for longer than expected.
Why the relative does not pay the stamp-duty surcharge
One genuine structural advantage of the security route over simply adding a relative to the deeds: a relative who only provides security takes no share of the property and is not a buyer for stamp-duty purposes. Their involvement does not, by itself, trigger the 5% additional-property surcharge that can catch a relative who already owns a home and goes onto the title as a joint owner (HMRC; Finance Act 2003).
That is the same trap set out in the joint-buyer stamp-duty trap and in how stamp duty treats a joint borrower sole proprietor mortgage: the moment a homeowning relative takes a beneficial interest, the surcharge can apply to the whole purchase price. A security-only role sidesteps that — but a conveyancer confirms the position on the actual facts.
The charge that lingers: the relative's own plans
A charge over the relative's home does not just sit there quietly. While it is registered at HM Land Registry it is an encumbrance on the property, and it can:
- complicate the relative's own remortgage, because a new lender will want the existing charge accounted for or consented to;
- reduce the equity available for a later equity-release or lifetime-mortgage plan;
- need to be discharged before the relative can sell or refinance freely.
None of that is a reason to rule these products out — they exist precisely to get buyers onto the ladder without a cash deposit. It is a reason for the relative to go in with the same clarity the borrower has about the monthly payment.
A worked anchor
Take a £250,000 first home — close to the £254,366 average across 76 sales in Liverpool's L1 8AX postcode in 2025, where individual prices ran from £129,950 to £450,000 (HM Land Registry). With a 100% springboard loan the borrower puts in no cash; the relative locks £25,000. At the Bank of England's 4.32% benchmark (April 2026), a £250,000 repayment mortgage over 25 years works out at roughly £1,364 a month — though a 100% loan usually carries a higher rate than the 75% LTV benchmark, because the lender is exposed to more of the price. You can model the monthly figure on the mortgage calculator and test what income supports it on the affordability calculator. On top of the mortgage, Liverpool's council tax Band D is £2,673.59 for 2026-27 (gov.uk).
For how the same family-help question looks from the borrower's side, see joint borrower sole proprietor versus guarantor mortgages and how to remove a parent from a JBSP mortgage. More are in the buyer guides section.
Based on 879,402 Land Registry transactions registered in England and Wales in 2025 and the Bank of England's most recent quoted mortgage rates — see the Homecost blog for how these figures are compiled.
This is general information about how these products are structured, not financial, mortgage, tax or legal advice. A security provider's savings or home can be at risk. Speak to a qualified adviser before acting.