A Belfast restaurant planning to add a dining room has to fund the building work months before the extra space starts bringing in customers. The owners already have commercial premises, but do not want the refurbishment to consume money needed for employees and suppliers. Keeping regular property payments lower during the work could make a difference.

An interest-only mortgage offers that possibility by postponing repayment of the borrowed capital. The arrangement reduces the amount due each month compared with an equivalent capital repayment mortgage, but leaves a debt that must be cleared later. The question is whether the business has a credible way to meet that obligation.

With an interest-only commercial property mortgage, the regular payment covers interest on the outstanding balance. Unless the borrower makes additional capital payments, the amount originally borrowed stays the same throughout the interest-only period.

Take a £400,000 mortgage with an illustrative annual interest rate of 6%. On an interest-only basis, the monthly payment would be £2,000 before any fees. Over five years, the business would pay £120,000 in interest if the rate remained unchanged, yet still owe the original £400,000.

A capital repayment mortgage would involve higher regular payments under comparable terms because some of the money would reduce the outstanding debt. This means the amount owed gradually falls, rather than remaining untouched until the end of the agreement.

The distinction becomes relevant when a business owns premises and needs funding for something beyond the property itself. A Belfast wholesaler might have a warehouse worth considerably more than its outstanding mortgage, but need another £180,000 to purchase stock for a newly awarded contract.

For a business that needs capital from property it already owns, Capify offers secured funding for working capital, equipment or refurbishment without selling the premises. Whether this funding is available on interest-only terms, and whether properties in Northern Ireland qualify, would need to be confirmed.

A lower mortgage payment is most useful when the money retained has a defined role in the business.

A manufacturer expanding production may have to purchase machinery and hire employees before the additional orders produce income. Paying interest rather than capital during that period would leave more money available for those expenses.

The arrangement becomes less convincing if the business has no clear plan for the capital repayment. Increased sales might cover the regular interest, but that does not establish where the outstanding mortgage balance will come from several years later.

Interest-only commercial mortgages may also appeal to landlords whose properties produce rental income. An owner of several commercial units might use part of that rent to cover borrowing costs while retaining money for maintenance and periods without tenants.

The calculations depend on the tenancy arrangements. If a Belfast office building has three tenants and one leaves, the landlord may lose a sizeable share of its income while the mortgage payments continue. Finding another tenant can take time, and repairs or alterations may be needed before the space is occupied again.

An owner-occupied property creates different circumstances. A restaurant or warehouse operator normally relies on trading income rather than rent to cover its mortgage. If orders fall or customers pay late, money…