De-commissioning of warm air system

[jhk]

Can anyone help? I've recently moved into a 1970's bungalow that at some stage must have had a gas boiler under floor warm air system. All that remains is the tin-like metal ducting under the concrete floor. (no visible signs of asbestos) The inside of the ducting is damp and rusty. Each room has a small brick size hole/vent in the floor. What's the best way to seal these up? Is it OK to fill them in with concrete or will the damp from the ducting eventually penetrate up through the floor?

 

[Agile]

You need to find out why its damp!

Most in/under floor cavities are very dry.

I suspect you may have a leaking pipe which is causing them to be damp

Whats UNDER the floor?

Tony

 

[jhk]

No water pipes pass under the floor that I'm aware of. Dampness in the ducting looks like condensation. Ducting appears to be be set in concrete floor approx 6" under the surface.