fluids from the zone outside the enclosure through the junction region to the inside of the enclosure for hollow block walls the conduit may extend from the junction region to the block passageways for solid walls the conduit may extend from the junction region through the wall a baseboard 21 has its upper portion 22 sealed to the inside surface of the wall at a level above the interior openings of the conduits and its lower portion 23 sealed to the inside surface of the floor a small distance from the intersection of the hollow block wall and floor slab or foundation footing and floor slab the baseboard is impervious to radon gas and fluids and is sealed to the wall and floor so that radon gas and fluids collected at the junction region cannot seep around the baseboard or escape from behind the baseboard into the enclosure the baseboard extends around the entire inside perimeter of the enclosure forming a collector that is in communication with all of the conduits it may be made of a flexible vinyl material and may be bonded to the floor and walls with a sealing adhesive such as expoxy the collecting means may be extended to seal additional.