Leaking supply pipes, blocked or broken drains are simple to diagnose. However, moisture rising up a wall defies gravity and has been shown more likely to be moisture drop out caused at the cold base where the wall meets the high mass of the ground. Is it cold, is there a suitable skirting or plinth?
Perpetual drenching from the simulated driving rain of controlled synthetic testing allows for the prediction of failure when applied to modern building materials and junctures.
Did it fall out of the sky or drop out of the air? When water is running down the walls a roof leak seems so plausible, remediation begins without properly investigating and diagnosing the problem. The symptom is tackled, but not the cause.
It’s easy to diagnose broken drains, blocked gutters, leaky lead pipes, penetrating and rising damp, but more often than not the problem is condensation. Condensation can literally run down the walls when it’s raining or before, looking like a roof leak or the result of a broken gutter. But what is the real source of the symptom?
Black mould – is where pure clean distilled water (condensation) is condensing on the surface which would imply that there is a vapour impermeable layer which could be a layer of vinyl paint; PVA; or damp stopper all of which can be concealed by matt paint or paper not visible on the surface.
Tannin stains – are where moisture has arrived from the substrate to the surface as a liquid, not vapour, and has carried the tannin that is naturally occurring in the masonry. It can be caused by water penetration but it can also be caused by condensation.
The combustion of natural gas produces water.
- 1m3, of natural gas (100,000 BTU, 3 kWh) can produce 2 litres of water.
- 1m3, of natural gas (100,000 BTU, 3 kWh) can produce 1.5 litres of water.
First answer has mislaid reference, second answer from here
scroll down through the thread, author stands corrected.
100,000 BTU = 1m3 gas
water = 3.25 pounds 1.474175kg
Alterations, extensions, conversions and going open plan. Mitigating modern building layouts and designs.
Downstairs emancipation, an open plan kitchen has increased moisture. Upstair modernity, double glazing and loft insulation have made the walls relatively colder. Moisture is no longer dissipated, it’s condensed on the walls.
Remediation and decoration. Retail therapy, denial and failure demand.
Source to symptom
Vapour is invisible and adds buoyancy to air, creating convection currents.