Saffron for Intermediaries has completed the largest self-build loan in its history, issuing a £4.8 million residential mortgage to support the redevelopment of a luxury home in Kensington.

The deal, facilitated by specialist broker Propp, exceeded the lender’s standard £4 million maximum and was more than a year in the making.

The loan will fund an ambitious renovation project led by a prominent London lawyer, including a full basement excavation to accommodate a private cinema, glass-sided extensions, and a bespoke £250,000 kitchen. The property is an end-of-terrace home in one of the capital’s most sought-after postcodes.

Despite the deal surpassing Saffron’s typical lending cap, it was made possible through what both firms described as a “solutions-focused approach”. Discussions began informally during a Propp charity event, eventually leading to internal approvals at Saffron and a cap override.

“This was a standout case in every sense – a high-calibre client, an ambitious project, and a result that exceeded the boundaries of standard lending,” said Lee Williams, national sales manager at Saffron for Intermediaries. “It speaks volumes about what’s possible when we combine specialist knowledge with genuine partnership.”

The loan completed at 70% loan-to-value, despite a down valuation during the process. According to Saffron, it is a clear example of the kind of complex case the mutual is willing to take on with the right broker support.

Peter Williams, chief executive at Propp, added: “This was the kind of project that tests the boundaries of traditional lending. Another broker might have told the client it wasn’t doable, but by bringing our specialist expertise to the table and working closely with Saffron, we were able to structure a deal that supported the client’s vision from start to finish.”

While this project represents the top end of the self-build market, Saffron says the sector is seeing increased demand across all price points. Its average self-build loan so far in 2025 stands at £820,000, with loans for sub-£1 million projects averaging £511,000 and those over £1 million coming in at £1.79 million.

The lender’s research also highlights a shift in demographics, with younger borrowers showing greater interest in custom and self-build opportunities. Some 64% of 18–24-year-olds said they are considering or already undertaking a self-build, compared to just 21% of those aged 55 and above.