The Sanatorium was added to the Hospital in 1877 as an 'Isolation Hospital' for infectious diseases as many patients were admitted with Tuberculosis and other infectious diseases. As well as patients that developed these illnesses whilst being patients at the Hospital. The site of the Sanatorium was the best in the hospital grounds. It was built on high ground south of the Farm and overlooking the Exe Estuary and Woodbury Common. It contained the same requirements as the main hospital e.g. administration block, kitchen, scullery, laundry, drying closet, and most importantly a disinfecting chamber. It was to accommodate 20 patients and was a compact unit, well suited to the nursing of infectious diseases.
During the First World War years 291 patients died from Tuberculosis.
As Tuberculosis had virtually disappeared by the early 1950's, the Sanatorium was no longer needed as an Isolation ward. The conversion from being an isolation ward was carried out in two stages - Stage 1 in 1953 and Stage 2 in 1955. Any Tuberculosis patients were treated in side rooms on the Medical Ward - Ward 19.
On a clear day you could look across from the Sanatorium and see The Wellington Monument located on the highest point of the Blackdown Hills, Somerset.