The Cavity Tray is an internal moisture or water barrier made up of a number of trays. The purpose of it is to prevent rainwater from penetrating any cavity wall and causing water damage to any windows and doors within a conservatory or orangery design. Damp typically occurs as a result of rainwater soaking external brickwork and forcing its way into the cavity between the inner and outer walls. Serious consideration should be given to a cavity tray when the external wall of the house is modified into a rear internal wall to accommodate a new conservatory, orangery or solid roof installation.
Most modern bricks are susceptible to absorbing water which is why a lot of newly built properties have small plastic vents positioned above ground level windows and doors. They’re better known as ‘weepers’ and are designed to let rainfall flow out of them when they connect with the lintel supporting the brickwork above the windows and doors. Despite these ‘weepers’, some of these buildings still require a cavity tray.