Family Building Society launches 100% Mortgage - here's what you need to know and how to qualify

Saving for a deposit remains one of the biggest challenges for many homebuyers in the UK. With rents high and everyday costs continuing to rise, many aspiring homeowners find themselves mortgage-ready in terms of income — but stuck when it comes to building a deposit.

That’s why the recent launch from Family Building Society has attracted attention across the market.

The lender has introduced an enhanced 100% loan-to-value (LTV) Family Mortgage, designed to help buyers purchase a home without contributing a traditional cash deposit — provided they have family support in place.

How the 100% Family Mortgage works

Unlike most standard mortgages, this product allows a buyer to borrow the full purchase price of a property, typically with help from the Bank of Mum and Dad. 

Instead of providing a deposit themselves, a family member offers security equivalent to 20% of the property’s value. 

Family members would have to agree to:

• Place their savings into the Family Security savings account, earning interest at 3.05% AER variable.
• Allow the Family Building Society to take a Collateral Charge over their property for the amount needed to make up the 20% of the new property purchase. This means a legal charge secured against a property that the family member already owns. 
• It is worth noting that terms and conditions apply to receive savings or have the Collateral Charge released.

Key features of the Family Mortgage: 

• Initial five-year fixed rate of just below 5.20%
• No application or product fees
• Up to 5.33 x single or joint income to work out how much you can borrow
• Minimum loan-to-value 80% 
• Minimum mortgage loan size: £96,000
• Maximum mortgage loan size: £750,000
• Available for purchase applications only
• Initial deposit from borrowers is optional, but not required
• The value of the additional security, plus any initial deposit, must equal 20% of the property value
• Up to a 40-year mortgage term to support affordability

Aaron Strutt, product director at Trinity Financial, says: "This is a nice offer from the Family Building Society, but you may be better off getting another low deposit option or even a loan from your family if possible. With this new mortgage, the family’s security is typically held during the fixed-rate period and may be released at the end of the term, subject to conditions being met.

"This means parents may struggle to recover their funds if the mortgage is in arrears or the property is in negative equity. This mortgage is similar to one offered by Barclays and other smaller building societies, and its structure allows buyers with high incomes but limited savings to move forward sooner than they might otherwise.

"The lenders are offering more low-deposit mortgages now because there are so many first-time buyers. Recent figures show first-time buyers now account for 48.3% of purchases in London, up from 22.4% a decade ago."

Mortgage lenders offering more low-deposit mortgages 

Deposit requirements have long been the main barrier to entry for first-time buyers.

While 5% deposit mortgages are widely available, even raising that initial amount can be challenging for some — particularly for those renting in London and the South East.

Products like this reflect a broader shift in the market: lenders recognising that affordability and deposit accumulation are two very different challenges. However, it’s important to understand that 100% borrowing comes with considerations. If property prices fall, there is a greater risk of negative equity. Family members providing security also need to fully understand their exposure and obligations.

What are the alternative mortgage options?

A 100% mortgage is not the only route for buyers with smaller deposits. Other lenders are offering very low deposit mortgages, like Accord Mortgages and Skipton for intermediaries.

95% mortgages (5% Deposit)

Many mainstream lenders offer competitive 95% loan-to-value products. For buyers who can raise a modest deposit, this often provides:

• Greater product choice
• Potentially lower interest rates
• Reduced long-term risk
• Less family arguments if something goes wrong

98% mortgages (2% Deposit)

Some lenders, including Santander, have introduced 98% loan-to-value options. These can be suitable for buyers who have saved something but not quite enough to reach 5%. Many borrowers prefer to take these to avoid renting and get on the property ladder.

Joint Borrower Sole Proprietor (JBSP) & Guarantor Options

In some cases, parents can support borrowing power by going on the mortgage (without being named on the deeds), helping boost affordability without requiring full 100% borrowing. This structure has different implications for tax, liability and long-term planning, so tailored advice is essential and required by most lenders.

Is a 100% mortgage the right choice?

It depends entirely on your circumstances. A 100% family-assisted mortgage can be a smart solution when income is high and stable, family support is available, the property is intended as a medium- to long-term home, and all parties understand the risks involved.

In some situations, saving a small deposit and accessing a 95% mortgage may be more cost-effective over time, but it depends on rates and how long you need to be fixed for. The most competitively priced low-deposit mortgages tend to be shorter-term two-year fixes. The key is understanding the full picture — not just getting onto the ladder quickly, but doing so sustainably.

How Trinity Financial can help

At Trinity Financial, we specialise in helping clients navigate complex and specialist mortgage solutions.

We’ll help you:

• Assess whether a 100% mortgage is suitable
• Compare low deposit mortgage products across the market
• Structure family-assisted arrangements correctly
• Understand the risks and long-term implications
• Secure the most appropriate deal for your circumstances

If you’re exploring low-deposit options or wondering whether family support could help you buy sooner, speak to our team for expert, tailored advice.

Lending solutions with Trinity Financial

Are you looking to buy a property and require expert advice? We’re here to help you find a solution – no matter how complex your circumstances. Our expert brokers have extensive experience providing creative solutions to secure mortgages for our clients.

Call Trinity Financial on 020 7016 0790 to secure a no deposit or low deposit mortgage, book a consultation or use our appointment calendar

The information contained within was correct at the time of publication but is subject to change.

Your mortgage is secured on your property. Your property may be repossessed if you do not keep up repayments on your mortgage