damp on floor joists with low ventilation

[Gary111]

hi, i have a 1930s terrace with wet joists on the front wall, it has a full width concrete slab at the rear.

there are no vents at the rear
i notice some houses have increased the size of the front vents.
is that likely to solve the problem ?
or does it need flow from front to back somehow ?

(its probably also had wall insulation which nay be blocking the vents )

i also had an idea of installing some kind of drainpipe or duct based vent from the rear wall that runs under the kitchen units plinth to the wooden floor, maybe it would go up to the roof at the back to get maximum air flow.

i also have a dis used chimney in the kitchen (rear) area dont know if i could use that in some way ?

i suppose another idea would be to add ducting to the existing front vents to roof level to gain more air flow ?

thanks

 

[foxhole]

When rear slab was laid it should have had pipe laid through it to front sub floor .
No vents are required to roof level.
You could introduce small vents in timber floor to rear to help flow .

 

[KenGMac]

Gary111, good evening.

All as foxhole above.

Have you checked to see if the air bricks in the front elevation are indeed as clear as possible? that would be my first action, a bright torch from the outside and if easy to get at a look under the floor [if possible?]

Ken.

 

[screamer]

are the joints wet just near the wallplate on the external wall?
if they are, check to see the level of what is on the outside (earth/slab etc), it maybe too high and above the DPC level and letting moisture in through your wall

 

[Gary111]

thanks for your replies, i do think the ground level may be a bit high, but its a public pavement so nothing much i can do about that.

 

[screamer]

you can get the walls injected with a DPC that should stop the water coming through to the joists