What is a commercial mortgage?
A commercial mortgage is a long-term loan secured against a commercial or semi-commercial property. Unlike development finance or bridging loans, commercial mortgages are designed for holding — you're buying or refinancing a property to generate rental income over a period of years, not months.
Commercial mortgages fund a wide range of property types: offices, retail units, industrial warehouses, pubs and restaurants, care homes, hotels, and mixed-use buildings with both commercial and residential elements. Terms typically range from 3-25 years, with interest rates from around 5.5% per annum.
The key difference from residential mortgages is that commercial lenders assess the property's income-generating ability, not just the borrower's personal income. Rental coverage ratio (how comfortably the rent covers the mortgage payments) is the primary affordability metric.
How rental coverage ratio works
Rental Coverage Ratio (RCR), also known as Interest Cover Ratio (ICR), is the relationship between the property's annual rental income and the annual mortgage interest payments. Lenders typically require an RCR of 125-200%, meaning the rent must be 1.25-2.0x the interest payments.
For example: a property generating £50,000 per annum in rent with a mortgage interest cost of £30,000 per annum has an RCR of 167%. Most lenders would be comfortable with this level of cover.
Multi-let properties (offices, retail parades, industrial estates) are assessed on the weighted average rental income, accounting for any vacant units. If 2 out of 10 units are vacant, the lender may calculate RCR on 80% of the potential income — or they may stress-test using the current income only.
Lease length matters significantly. Lenders prefer properties with long, secure leases (5+ years remaining) from creditworthy tenants. A single-let warehouse with 15 years remaining to a PLC tenant is much easier to finance than a multi-let office with 6-month rolling tenancies.
Property types and lender appetite
Standard commercial property types (offices, industrial, retail with established tenants) attract the widest range of lenders and the best terms. Rates from 5.5% per annum, LTVs up to 75%.
Semi-commercial (mixed-use) properties — typically a shop or office with a residential flat above — are widely available from both high-street banks and specialist lenders. The residential element often improves the lending proposition because it provides a diversified income stream.
Specialist property types (pubs, hotels, care homes, petrol stations) require specialist lenders who understand the operating business as well as the property. These are assessed as going concerns — the lender evaluates the business performance, not just the bricks and mortar. Rates are typically higher (7-10%) and LTVs lower (50-65%).
Development sites, land without buildings, and properties with significant planning potential are not suitable for commercial mortgages. These require development finance or bridging loans.
Fixed vs variable rates
Commercial mortgage rates are available as fixed or variable. Fixed rates provide certainty of payments for a set period (typically 2-5 years), after which the loan reverts to the lender's standard variable rate. Variable rates track Bank of England base rate plus a margin.
Fixed rates are generally 0.5-1.0% higher than equivalent variable rates, reflecting the cost to the lender of guaranteeing your rate. In a rising rate environment, fixing early provides protection. In a falling rate environment, variable rates become more attractive.
Consider your investment horizon. If you plan to hold the property for 10+ years and want payment certainty, fix for the longest available period. If you might sell or refinance within 2-3 years, a variable rate avoids early repayment charges that apply when breaking a fixed-rate deal.
Related Services