I am midway through a renovation project where half of the property is being re-developed and the other half left untouched. I have been told I need full radon protection in the new section. I can upgrade the membrane without a problem, (although it seems crazy as the membrane cannot be tied into the existing walls...) but installing a Radon sump is going to be awkward. The foundations under th external walls are over 2ft thick and I'm not sure how I'm going to get a 4 inch pipe through that. Is there any way round installing the sump while concurring with building regs? And if I have to do it am I better with pre-fabricated sump or a brick built one?
I work for one of the biggest manufacturers of redon protection membranes etc. Basically a Radon Sump can work in two ways:
Firstly you can install it so that the outlet pipe comes vertically through the house and terminates at the ridgeline of your roof. This can then work as a "passive" system ie with no fan fitted. It works by the heat of the inside of the building warming up the air within the outlet pipe. As you know hot air rises and the Radon gas (which is about 8 times heavier than air) is drawn off.
This system has the advantages of being cheaper than using a fan, quieter and maintenance free. You may still have to monitor gas levels within the house for a period after installation and if levels are still too high you then still have the option of fitting a fan somewhere along the pipe to turn it into a stronger "active" system.
The second method of installation is to have the outlet pipe from the sump running horizontally under the building and then running vertically up one external elevation of the building to eaves level. With this method you will need to fit a fan from the outset as it will not work as a passive system.
I hope this is of some help but I would agree with welsh brickie that building control might be able to offer help.