A condition survey of NHS-owned buildings including the Gilbert Bain Hospital will take place in the autumn.
The survey will be carried out by external contractors for Health Facilities Scotland, a meeting of the board of NHS Shetland heard this week.
NHS Shetland chief executive Ralph Roberts said it will give a “sense of the life span” of NHS property, particularly the Gilbert Bain Hospital.
The survey will enable the board to make a decision about the future of the hospital, which could be 10, 20 or even 50 years, he said, and then if necessary to target the board’s capital programme.
Mr Roberts said the hospital is a “complex building” which looks good inside but beneath the surface are engineering systems of pipe work and steam work which no-one sees. The condition of these systems will not be known until they are uncovered in the survey.
Interim head of estates Lawson Bisset said there was a backlog of maintenance to be done in the hospital, and the survey would show how long the building could last, depending on the amount of money available.
Mr Roberts said: “We are making sure the engineering is as good as the decor. We will get that level of information from the survey.” A new hospital could therefore be anything up to 50 years away.
Meanwhile the board is to sell its old headquarters Brevik House, which is surplus to requirements since the board moved to Montfield.