Blown Air Heating Ducting problems

[Jonathanacsb]

Not sure if anyone can help?
The watertable at my mums property has risen and now allows damp and water into the ducting which is obviously too low.
Is there any way a lining can be put in to stop the water ingress?
New soakaways were dug in an effort to stop this but the problem has returned this year.
The property is a bungalow with a concrete floor.

 

[45yearsagasman]

There is, by the sound of it, no membrane to prevent this happening, and I cannot think of any procedure that would waterproof the ductwork.
Cutting up the floors would be out of the question due to labour and it really would not achieve much as the problem the lack of membrane.
It may be time to consider replacing the warm air system with a boiler and rads.