Raise pressure; under-floor ventilation
Floor type: Suspended floor
Underfloor ventilation systems provide a high impact radon solution designed specifically for suspended floors. They are used where there are not enough air bricks present, and/or where radon levels are too high for natural airflows to reduce the radon present. Under-floor ventilation systems use both dilution and positive pressure principles to achieve radon reduction, by ventilating a space with air and raising the pressure in the sub-floor void. They can be used on a range of radon levels, even over 1000 Bqm-3.
In-wall systems can be fitted where there are thick walls or concrete suspended floors, and there is enough distance between the bottom of the floor and ground level outside. If these parameters are not available then a boxed under-floor ventilation system is a very neat and compact solution, which replaces an existing air brick. For larger properties UK radon Ltd fit a large boxed under-floor ventilation system, which have huge flexibility for adjusting airflows. See also BRE quick guide 2 for more information.