London's student-rental market is a rental-income underwriting question
A large share of London's investor activity clusters around the university and college catchments, and buying a property to rent by the room is not underwritten the way a single-tenant rental is. Two things decide these files. The first is how the lender counts the rent: a rental add-back adds roughly half the gross rent to your income, while a rental offset nets a larger share — often around 80% — directly against the property's carrying cost. On a property whose rent is strong relative to price, which is the usual London case, the offset method is materially more generous and can be the difference between qualifying and not. The second is what the property legally is. A house rented to several unrelated students may be a lodging house under the municipality's licensing regime, and a lender's willingness to fund it — and an insurer's willingness to cover it — turns on that classification rather than on how the listing describes it. A non-owner-occupied rental also cannot be default-insured, so 20% down is the floor regardless of price. The exception worth knowing is the owner-occupied multi-unit rule: an owner-occupied duplex can use the insured tiered minimum (5% on the first $500,000, 10% above), and an owner-occupied triplex or fourplex can be insured with at least 10% down, on purchases up to $1.5 million — which in a market at London's price points is a genuinely different entry point.