Damp suspended floorboards

[ChasHyde]

Apologies to anyone who has read this before under my post - Ventilation Shaft?
I have a problem with damp edges to a suspended wooden floor in my 1905 semi. The damp was right by the threshold where it joined the tiled hallway floor. I removed the tiles etc that butted up to the wood, I thought that would would solve the problem - but no!
The damp reappeared, from the edge of the floorboards to about 3 inches into the room. The endgrain of the boards is now is now free of anything touching it, but the boards are getting damp - how? I have no idea, condensation? but the boards should not be that cold to cause moisture to condense on them should they?
The dampness is not that deep into the wood, a flash over with a heat gun gets it to go away, but it re-appears after a few hours.

 

[inwood]

My only thought is that the boards are currently saturated and when you're giving them a blast with a hairdryer you're only taking off the surface dampness hence a few hours later the dampness returns.

Alternatively you have a lot of damp air passing by the opening now made between the boards and the tiles. Is there a 'breeze' from this gap? If so the damp air may be coming from elsewhere.

 

[Matt Green]

The dampness is not that deep into the wood, a flash over with a heat gun gets it to go away, but it re-appears after a few hours.

How are you testing for damp? What's the appearence/symptom?

cheers


Matt

 

[Lime]

The same as the above posters.


What is under the suspended wooden floor like?
Is it airy and well ventilated or musty and damp?
How big is it?
Does it have ventilation at all?

 

[ChasHyde]

More info, as requested. The damp manifests itself as darker patches on the timber floor. I have lowered a lamp underneath the floor, there is no obvious sign of dampness, a pair of central heating pipes run underneath the floor where it is damp, but I have felt underneath the joist, and it does not feel wet. The pipes are at the bottom of the joist, not near to the floorboards at all.

I have cleared the holes in the airbricks all around the room, which is approx 3m square, (there are five in all, 9" by 6", two brick course ones ) and managed to see the light from my lamp through two of the airbricks, through a dwarf wall that has 'honeycomb' (missing half brick) airways incorporated into it. Whilst looking through the airbrick I was able to detect some airflow on my eyeball.

When I leave the back and front doors open all day, the dampness dries up completely - if it is a nice dry day, only to reappear overnight, when the doors are both shut. This tells me that the floorboards are not saturated, and they don't look it.

 

[Matt Green]

Are the boards varnished or otherwise coated with something impervious?

:?:

Matt