In a small IT department the roles matter less than the responsibilities, because one person carries four of them and the chart shows only their title. This page is the responsibility list rather than the role list: the fourteen things a small IT function has to own, which role usually carries each, and the three that are most often owned by nobody. Print it beside the chart and the gaps are visible in a minute. The structure itself follows the same span rule as the rest of the company, and the planner prints the manager count and layers for whatever headcount you enter.
The responsibilities support carries
The ticket queue and its response times, device build and handover for joiners, account creation and removal for joiners and leavers, and the asset register. The leaver half of that list is the one that slips: an account left open after somebody leaves is both a security finding and a licence being paid for, and it is owned by whoever owns the queue unless the chart says otherwise.
The responsibilities infrastructure and applications carry
Network, identity, backup and its restore test, endpoint management and patching on the infrastructure side; the business systems, their integrations, their vendor relationships and their upgrade calendar on the applications side. The restore test is the one that goes unowned most often, because a backup that has never been restored is a belief rather than a control.
The three that are usually unowned
Security policy and its review date, the software licence and renewal calendar, and change management for anything touching a business system. All three are cheap to own and expensive to discover unowned, and all three should appear as a name on the chart's key even when the name is the IT manager's for all of them.
Questions people ask about it organizational structure roles and responsibilities
Who should own the licence renewal calendar?
Whoever owns applications, with finance sighted. Unowned renewals are the most common source of surprise IT spend in a small company.
Do we need a change process at this size?
A named approver and a record is enough under about twenty people. What matters is that both exist and the chart says who the approver is.
How do we show one person carrying four responsibilities?
One box, and the responsibilities listed on the profile behind it. Inventing four boxes for one person makes the chart lie about the department's capacity.