Damp in join between floor and wall . Best course of action ?

[tsekul]

Hi There.

We have an 1800 century granite cottage in Cornwall which we are renovating or at least were until the Council said we need a bat survey and told us not to do any more renovations, but thats a different story !

We have a line of damp where the floor meets the solid walls. We are laying 60mm of insulting lime render on the interior walls and I am thinking of putting a mesh fillet in the corner so the damp is not in direct contact with the lime as I think the lime will keep drawing the moisture out due to capillary action. If there is an air gap then this will not happen to the same extend.

The wall that this concerns is situated close to the spring that supplies the water to the property so I can see the water level in the well and at the moment it’s quite high. This only concerns the oldest part of the building as the new section has a full DPC. All the floor levels are at good 200mm above ground level.

My concern is that if I just plaster straight into the corner the lime will just keep drawing the moisture through the wall due to the high water table. The previous owners had tanked the area to about a metre and gypsum plastered over it but this had failed so the plaster was blistered and crumbling.

Does anyone have any advice on this course of action or alternative ?

Thanks in advance.

 

[Cubist]

You don't say what type of floor you have and this may have a bearing on the best approach for a solution. Could you tell us more please?

My sympathies re your bat problem.

 

[tsekul]

Hi There,

The original section has a concrete slab that we believe was installed approx 20 x 30 years ago. This appears to be dry and sound. We are contemplating digging a pilot hole to ascertain whether there is any insulation and or DPC. But unsure whether to or not as obviously if you do that you may compromise it . The whole property was renovated some time ago. The architect thinks approximately 30 year ago as all the stud walls and floor beams have 400mm centres ?

 

[Cubist]

Damp at the edges of a concrete floor is usually associated with a DPM beneath it that is forcing rising moisture to push out into the surrounding walls. The nearby spring may be contributing to the problem but in addition the poor summer last year and the heavy and prolonged rains have resulted in an increase in ground water levels across the country. Given your location it could be too that the general depth of soils above rock are also quite shallow. Short of exploring opportunities to enhance drainage away from the affected walls of the house I suspect there may be little more you can do.

Hopefully other members reading this thread may be able to offer/suggest something better. Good luck.