Gentlemen (and ladies) Just been looking at a temporary studio for our company, a ground and lower ground floor of a really old building.

As I walked up the original stone steps I noted they were wet to the touch, no water from above. The guy said that they were sweating 🙂

Haven’t turned much up on Google, STW engineers, what say ye?

The place has been empty for 6 months so I was imagining that it might be like dew because of the cold empty building and moisture in the air?

Think they would be dry if we were in and using them?

I’d guess condensation

Yes – most likely.

The flags in my cellar are often damp like that but can also be bone dry in winter. Depends on atmospheric conditions as there is no water ingress.

my theory – Did you look at this property very recently? this year it has been very warm hence the ground/earth has warmed up considerably. At this point in time the air around us at times can be cool, much cooler than the ground upon which your stone sits. So the cool air falls on the stone and because this is warmer than the air itself it condensates.

To prove my point over next few weeks during autumn we will get some days when its frosty or v cold. If you have an outside tap wash your hands under the water – on days like this it will feel like the water has been thro a heater.

The place has been empty for 6 months so I was imagining that it might be like dew because of the cold empty building and moisture in the air?

^ This

So the cool air falls on the stone and because this is warmer than the air itself it condensates.

Wrong way round. When we go to my mums holiday house in the winter it’s pretty cold, when the air warms up it condenses on the toilet cistern as it’s full of very cold water. This is what’s happening with your stones – they’re cold and warm, damp air has just been introduced resulting in condensation.