A technical report describes the retro-fitting of low-cost controls into a small building constructed to house the Canadian Governor General's carriage. Built in the 1890s it is still used on cerimonial occasions. The interior of the building was subject to wide fluctuations in temperature and relative humidity. The article describes how RH stability was improved at the cost of no more than 2000 Can. Dollars. This involved use of UV absorbing film, blinds, a fan, a common household thermostat, a humidistat, an electric heather and a portable dehumidifier. Tables, diagrams, charts and references.