Wallbarn TPE vents, also called aerators, are designed to help aerate the concrete slab beneath, and help the structure to breathe. These vents are manufactured from TPE, a plastic / rubber compound. They are suitable for bituminous waterproofing systems. All concrete will retain an element of moisture within its mass after the construction process, and it is important that once the roof is waterproofed, this moisture has a way to escape the system, otherwise there is a risk that this retained moisture will build up and possibly bulge out of the top of the structure and cause the waterproof seal to bubble, blister or even burst.     The vent is designed to draw this moisture away from the concrete slab. It is placed onto the bare concrete beneath the waterproofing membrane and insulation. The membrane will then be applied over the base of the vent. This creates a flue which helps to draw the vapour out of the concrete. There are a series of ribs along the underside of the round base plate (or flange) and this encourages the movement of vapour along the base and into the tube (or flue). It also acts to alleviate any hot air which might appear between the slab and the membrane, often evidenced by blistering and bubbling of the membrane. Properties Height: 140mm. Diameter of the cap at the bottom (where is slots onto the pipe): 75mm. Diameter of the funnels at each side: 82mm. Material: Plastic.