Air bricks and condensation

[ChrisinShropshire]

We have a ten year old house in Shropshire. Since we bought it, we have been doing a number of jobs to get it the way we want before we move in.
It has, I believe, a suspended concrete floor with a void underneath. Recently, when it has been cold, my wife noticed that the ground in front of the air bricks was wet. I assume that this was caused ny the natural flow of "warm damp air" from the void meeting the below 0°C air ourside and condensation forming. The inside of the house is pretty dry (approx 50%r.h.).

Am I right that the damp is just condensation and that we don't have a dampness problem in the void below the floor?

Thanks for your help

 

[Alastairreid]

Block and beam with sub floor vents?

Try covering the vent and see if it gets rid of the cold spot.

 

[ree]

Your post is puzzling?
Can you take some pics of the air bricks in question?
Can you take pics of any exposed floors?
Is heating left on in the empty house?

 

[ChrisinShropshire]

When we are not there, the heating is set for 15°C There are also dehumifiers running in the house, so we are confident that the air is not damp.
I will see if I have any photos, but if not, I will get some when I next head home.

 

[ree]

Why are you using dehumidifiers?

What did your mortgage survey report say bout any of the above?

 

[ChrisinShropshire]

The survey was done on a rainy day in Oct/Nov, so it was not cold enough to have condensation and the effects would have been masked by the wet ground

 

[Bilabong007]

I'm confused.

Is the damp patch outside or inside the house?

 

[ChrisinShropshire]

It is outside. The slate chippings are wet. This is why I wonder if there is a flow of air from the void and, as it meets the cold, outside air, the moisture condenses.

 

[JohnD]

Have you got a water meter?

Does the bubble ever stop?

Why do you need a dehumidifier?

 

[ChrisinShropshire]

Yes, we do have a water meter.
I do not understand the bubble comment, but we do not have a water leak.
We leave the dehumidifer one a low setting as we are not there so often to air the house by opening the windows.

 

[JohnD]

If you aren't there, having showers, boiling kettles, and breathing, there is no reason why it should be humid. In cold weather, with the heating on low, it should be very dry.

When you look at the water meter, you will see, through the glass top, a little bubble which spins faster or slower depending on how fast water is flowing through it. When there is no flow at all, the bubble stops moving.

Does yours ever stop?