I have just moved into a 20 year old house, it has 15mm bore central heating pipes upstairs and microbore (?) downstairs. There is a constant knocking evey second for the entire time the heating is on (i.e. not just when the pipes warm or cool). Could someone explain the cause and cure without ripping all the floorboards up?
It appears to originate near the pipes under the radiator in the box room but it is hard to precisely isolate the source of the noise.
Any ideas?
K