Condensation and water in the subfloor void

DarrenWoo

We had a musty smell coming from the front room. I lifted the floorboards to find condensation all through the subfloor of this room. Even on the plastic damp course protecting the wood. The void continues on to the living room which was condensation free.

I dryed the underfloor which got rid of the condensation, the only issue is when it rained heavily. A puddle started to emerge from around the bottom of the chimney stack. This got bigger and bigger until the rain stopped. At this point the water drained leaving a the cement floor wet. Its a 1930s semi with no damp course under the cement floor.

I have checked the roof, chimey, walls, guttering and all seem fine.

The water is coming in from the wall that I share with the neighbours. I did have some air vents blocked, which are now unblocked. In addition, when the extension was built, the airbricks weren't extended. I threfore only have 3 airbricks in the bay window area. These bricks are around 2 courses higher than the ground.

Having looked under the floor a good number of times, the water getting in and is causing the bricks to get condensation on them. Then i presume that over time this condensation get worse.

Is this likley just groundwater or is there something i have missed? The airbrick situation isnt ideal either.

The two photos show what happend after very heavy rain. Perhaps worth pointing out that the house is buillt on clay. It is also muted that in the area of where i live there is a spring running through. The floor was replaced many years ago due to it going rotten. Hoever, this is the first issue (we know of) in 15 years. The extenstion was added 5 years ago.

I have attached a photo showing the extent of the condensation on the joists. Luckily, once dried out, there are no signs of wet/dry rot or any defects. Lucklily we used treated timber. I have also removed as much of the cavity wall insulation as i can

NickRMC

I realise this is an old post, but did you get anywhere with resolving? I have condensation too, localised to any area under my daughter's bedroom, my main concern is rotting of the timbers, mold and smell.
Any tips on how to resolve much appreciated, thanks.

Okey00001

I have raised this too as I have a similar problem with water ingress.  For us, it transpires that we have a high water table. I think this problem was there when we bought the house and before we had a new driveway.

We had block paving driveway with good soak away. drainage system. 

The drains, gutters are all clean, new and no problem.  

Ventilation - We have been told, that it is important to have ventilation.  This will avoid condensation and rotten timber. It does smell damp after stormy weather.  The airbricks are clear and good, but think we need to have another airbrick/vent put in.

Can you update us with your situation? How did you get on?