Damp airbrick - normal?

[MidsTW]

So the air bricks at the rear of the property and the some at the side are damp, and water settling on the adjacent floor.

Is this just the normal function of an airbrick removing moisture from below the sub floor?

 

[Bonni]

Air bricks are fitted to allow timber floors to breathe. As long as your ground level is 6" below DPC and the timbers are sat on DOC material, then all is good.

 

[MidsTW]

Yeah this is a new build so the floors aren’t timber. But still a requirement to allow the space below to breathe, that’s right isn’t it

 

[^woody^]

If these are venting an underfloor void, then you would not be getting any moisture out of them.

What can happen, is the plastic air brick and the duct it is connected to may not be sealed or properly connected, so you end up with some moisture from the cavity exiting the vent and the concentration due to the plastic, make the ground a bit damper at that location.

Or the damp course arrangement around this can give the same effect - if those white spots are efflorescence and that is where the damp course is then that's the reason.

Its not a problem, just the way it is.

 

[Bonni]

Yeah this is a new build so the floors aren’t timber. But still a requirement to allow the space below to breathe, that’s right isn’t it

Not sure why you would want a concrete or block and beam floor to breathe? A concrete floor is solid so nothing to breathe and beam floors made out of concrete are not affected from moisture or fungi.

 

[^woody^]

Not sure why you would want a concrete or block and beam floor to breathe? A concrete floor is solid so nothing to breathe and beam floors made out of concrete are not affected from moisture or fungi.

What about the stale air void the void below it?

 

[Leofric]

A new build could still be a suspended timber ground floor.
You do ventilate the void below a suspended precast concrete beam and block ground floor.

 

[cAtLeYx]

I'd say there's something fundamentally wrong here. The DPC is clearly installed in the bed joint over the top of the air brick as the "peep" vent is evident to the left hand side of the air brick. The vent brick is therefore below the DPC and one would hope the cavity tray. There should be no evidence of water here from the cavity. The only other issue could be a high water table...!