Hot water

[terryplumb]

I suspect you may have a leak on hot water pipework. Any hot water pipes buried in concrete,or in under floor voids ?

 

[mattgoody1]

There will be under the floorboards but not under concrete

 

[terryplumb]

So there is a void under the flooring of the ground floor ,where domestic hot water pipes run ?
If so it's possible there is a leak.

 

[mattgoody1]

I'll try and chase the pipes from the cylinder to the boiler and see if I can see a leak. I think it goes straight down then across the ceiling of the garage into the boiler. So maybe between the false roof in the garage but that doesn't seem to be getting wet