Gen H mortgages tend to come up in one of two situations: a first-time buyer who can comfortably manage the monthly payments but needs family help to get the affordability sums to work, or a self-employed applicant whose income needs a closer look than a standard payslip would get. Either way, the lender’s name matters less than understanding three things — who owns the property, who’s liable for the mortgage, and what evidence gets used to assess the case.
If you’re a family thinking about supporting a purchase jointly, it’s worth reading our explainer on how a joint borrower, sole proprietor mortgage works first. It sets out the core principle behind all of this: you can take on responsibility for a mortgage without owning any part of the property it’s secured against.
What is a Gen H mortgage?
Gen H is the trading name of Imagine Mortgages Limited, and it offers standard residential mortgages alongside a few structures built specifically around affordability, family support, and complex income.
The one it’s best known for is the Income Booster. It lets an eligible family member join the mortgage as a borrower — so their income counts towards affordability — while the buyer stays as the sole owner on the property deeds.
That split matters. There are really three roles here: the owner holds legal title to the home, the income booster shares responsibility for the mortgage, and the lender holds security over the property. Gen H is explicit that a booster is on the hook for the full mortgage if the owner stops paying — this isn’t a symbolic gesture of support.
How can a Gen H mortgage use family income?
The booster goes through the same eligibility, credit and affordability checks as the owner — even though they may never intend to contribute a penny towards the monthly payments. For a first-time buyer, this can bridge the gap between what they can personally afford and what the property actually costs.
It’s a genuinely different arrangement from a gifted deposit, because the family member isn’t just handing over money — they’re signing the mortgage and taking on ongoing contractual liability for it.
A natural next question is whether the parent (or whoever the booster is) can just come off the mortgage later, once the buyer’s own income has grown. Gen H does assess whether the owner could support the mortgage alone at some future point, but removal isn’t automatic just because someone asks for it — it goes through a process, and depends on the affordability picture at the time.
Eligibility criteria — which relatives or supporters qualify, and at what loan-to-value — change from time to time, so it’s worth checking Gen H’s current Income Booster criteria before assuming a particular relationship or income level will work.
| Support structure | Property ownership | Mortgage liability | Main purpose |
|---|---|---|---|
| Income booster | Buyer owns the home | Booster shares full mortgage liability | Additional income supports affordability |
| Gifted deposit | Buyer owns the home | Donor is normally not a borrower | An unconditional gift increases the deposit |
| Standard joint purchase | Both applicants usually own the home | Both applicants are normally liable | Applicants buy and borrow together |
Isn’t this basically a guarantor mortgage?
Not quite, and the difference is more than semantic. A guarantor arrangement can take several forms depending on the lender — a limited guarantee, savings held as security, or property offered as security — but the guarantor usually isn’t a borrower in their own right.
An income booster is. They’re on the mortgage contract itself, which changes how their liability plays out — it can affect their own future borrowing, their financial planning, and their exposure if payments are ever missed.
We’ve written more on this distinction in our guide to guarantor mortgages and family assistance — the legal structure really does matter more than whatever it gets called around the kitchen table.
Given the liability involved, independent legal advice is genuinely important for anyone considering becoming a booster. It’s worth thinking through, before signing anything, what happens if payments are missed, if relationships change, if the buyer wants to sell, or if the booster later needs a mortgage of their own.
Does this affect first-time buyer status?
Because the income booster isn’t placed on the property deeds, using one doesn’t automatically disturb the buyer’s first-time buyer position — and Gen H presents this as one of the structure’s selling points. That said, your conveyancer still needs to confirm this holds for your specific transaction.
Under current HMRC rules, First-Time Buyers’ Relief requires that all purchasers are first-time buyers, intend to live in the property as their main residence, and buy for no more than the qualifying price cap. In England and Northern Ireland, that currently means no Stamp Duty Land Tax on the first £300,000, and 5% on the slice between £300,000 and £500,000.
Having a family member’s name on the mortgage doesn’t automatically make them a purchaser for tax purposes — but ownership, any trust arrangement, financial contributions, and separate family agreements can all affect how the transaction is treated, so it’s not something to assume your way through. Our broader guide to current stamp duty bands has more context, though a qualified tax adviser or conveyancer should always confirm the actual liability for your purchase. Scotland and Wales run their own systems, and the rules do change, so treat any figures — including these — as a starting point rather than gospel.
What about self-employed applicants?
Gen H does accept self-employed applications, but being accepted in principle doesn’t mean every pound shown in your company accounts will count towards affordability.
For a sole trader, company director or partner, what actually gets used depends on trading history, taxable profit, salary and dividend mix, ownership share, and how the business has performed most recently. It’s worth checking Gen H’s current self-employed criteria against the specific documents you have available, rather than assuming your situation fits a general rule.
Strong turnover and a healthy bank balance don’t automatically translate into strong affordability — different lenders calculate sustainable income differently, sometimes quite conservatively. We go into this in more detail in what self-employment looks like to a mortgage lender.
It’s also possible to combine self-employed income with an eligible booster’s income on a Gen H mortgage — but stacking a second borrower onto weak evidence doesn’t fix the underlying problem. Both applicant and booster go through the lender’s checks independently, and the booster’s own existing commitments can eat into whatever extra affordability they were expected to bring.
What evidence will you need?
This varies by role, but expect to need identification, bank statements, credit information, deposit evidence and income records as standard.
If you’re self-employed, that usually extends to finalised accounts, tax calculations, tax year overviews, and sometimes business bank statements. Our guide to accessing SA302s and tax year overviews explains where to get these and why the figures need to match up.
For a booster, the evidence needed covers their income and their own personal commitments — not just proof of the family relationship. Someone with a large existing mortgage, other loans, or dependants may add far less affordability than their headline salary suggests.
Working through the decision
Before settling on a structure, it helps to work through it in order:
1. Define the buyer’s shortfall
Separate a deposit problem from an affordability problem before choosing a family-support structure.
2. Establish each person’s role
Confirm who will own the home, who will borrow and whether any contribution is a gift or continuing payment.
3. Test current criteria
Assess the buyer and booster against Gen H’s live income, credit, age, property and loan-to-value rules.
4. Compare the alternatives
Consider suitable standard, family-assisted and specialist products by total cost, risk and flexibility.
5. Confirm legal consequences
Each party should understand liability, ownership, tax treatment and the process for changing the arrangement.
What families should think through before applying
It’s worth treating this as a long-term financial commitment rather than a one-off favour. The booster’s liability can sit there for years, and it may well come up again in their own future credit applications or retirement planning.
There’s also a harder question worth asking upfront: what happens if the buyer still can’t afford the mortgage alone by the point everyone assumed the booster would come off it? Gen H’s process anticipates a future removal, but income, outgoings, property values and lending criteria can all shift in the meantime — none of it is guaranteed.
It’s worth having a direct conversation early on about monthly contributions, what happens if a payment is missed, how sale proceeds would be split, what happens if relationships change, and roughly when the booster expects to be released. If any contribution is meant to create a right to repayment or a share of the property’s value, get a solicitor to document it properly — don’t leave it as an understanding between family members.
When comparing a Gen H mortgage against other routes, look past the headline borrowing figure to the interest rate, product fee, early repayment charges, term and total amount repayable. A bigger theoretical loan isn’t automatically the better — or safer — choice.
In Summary
A Gen H mortgage can bring family income into the affordability calculation without putting anyone else on the property deeds, and it does consider self-employed applicants under its own criteria. It’s a genuinely useful structure for a real affordability gap — but it also transfers serious, long-term mortgage liability onto whoever agrees to be the booster.
Ownership, affordability and the exit plan all need to be looked at together, not in isolation. Independent mortgage advice can help you work out whether Gen H — or a different lender entirely — is the better fit for your circumstances, and a conveyancer or tax adviser should always confirm the legal and tax position before you commit.
Frequently Asked Questions
These answers cover the main questions surrounding Gen H, family support and complex income, although the lender’s current criteria must be checked for every application.
What is a Gen H Income Booster?
An Income Booster is a person whose eligible income supports the mortgage application without that person becoming an owner of the property. The booster becomes a borrower and can be liable for the full mortgage.
Does an income booster have to make monthly payments?
Gen H states that the booster does not have to contribute while the mortgage remains in good standing. The booster can still become responsible if the owner fails to make the required payments.
Does an income booster own part of the home?
No, an income booster is not normally named on the property deeds under the Gen H structure. Any separate contribution or family agreement should be discussed with a solicitor.
Can an income booster be removed later?
Removal may be possible when the owner can support the mortgage independently and completes the required process. It is not guaranteed merely because the family expected the arrangement to be temporary.
Can a Gen H mortgage help a self-employed buyer?
Gen H accepts self-employed applications subject to current criteria and satisfactory evidence. The assessable income may differ from turnover, money retained in the business or the amount the applicant considers available.
Is an Income Booster the same as a gifted deposit?
No. A genuine gifted-deposit donor normally gives money without repayment and does not join the mortgage, while an income booster becomes a borrower whose income supports affordability.
Will a parent’s property automatically cause higher stamp duty?
Not necessarily, because a non-owning income booster is not normally a purchaser of the new property. The conveyancer must confirm the position from the ownership structure and the complete circumstances.
Does passing the Gen H calculator guarantee a mortgage?
No. Any initial affordability result remains subject to the lender’s criteria, evidence, credit checks, underwriting and property assessment.
Should family members obtain legal advice?
Yes. A booster accepts mortgage liability without automatic ownership, so independent legal advice helps clarify the risks, responsibilities and consequences of entering or leaving the arrangement.
