Damp issue..

[joidevie]

Hi.. We've just re-awakened a village house in Herault which has been effectively closed up for 9 years. We moved in after several days of heavy rain and many of the ground floor walls were pretty damp, if not wet. No big surprise, and even a bonus as we could strip much of the wallpaper effortlessly!

However, one area by a front window remains pretty damp after 2 weeks of airing the house, and in this area the interior wall has been boarded to shoulder height with asbestos panels implying that it has been an ongoing problem. The tomettes on the floor there also seem to be 'soft' under foot (ie. coming away from the mortar). Poor things, they had been covered in lino for years.

Some of the render outside at around shoulder height is also coming away in a small patch (it has been re-done along the whole front to shoulder height)..

I presume this is a rising damp thing? Or could this just require more time to 'dry out' and then lift the asbestos panels away and render the internal walls? Would a membrane simply direct the water to other areas?

It's my first experience with this - my last place was a barn where I'd re-pointed the interior walls, and these would perhaps only go a little dark after heavy rain and simply dry out within a day or so..

Many thanks..

[Théière]

More time, more fresh air to start with. What are your walls made of? Applying render to some soft stone will allways have the same outcome.

[Gluestick]

Best advice I was given ten years ago was dry the place out and plan after it has been well aired and warmed.

An old French house will not enjoy a floor membrane: nor a DPC in walls. it is naturally self-conditioning.

Injecting a chemical DPC for example, will invariably "Kill" the walls and the mortar will crumble.

Most important (As we found) was to install wall ventilation grilles: and encourage through draft.

 

[joidevie]

Hmm...  Much as I suspected. The walls are soft stone & mortar with the inevitable render to front and chalk 'plaster' to inside..

The walls must be 50cm thick - no issues with fitting vents?

Many thanks as ever..

[Gluestick]

Like Norfolk "Dutch" flint cottages: if these walls dry out: then they tend to collapse!

Fitting suitable vents in stone walls is probably best accomplished by carefully removing stones and inserting PVC gutter down-pipe, with the grilles on each end. Which is exactly how I did mine.

Interestingly, for the first three years, each and every Spring, the tiled floors were absolutely covered in condensation: it was so bad I purchased a grunty Amcor De-Humidifier.

As the cross-draft has worked and heat added and plenty of open windows when the weather allows, then this problem (sorry about the pun!) evaporated!

Are the walls cavity? Some are. Normally, however, they tend to be stone either side and rubble and mortar infill: which process goes back to Medieval building types.

Placing a PVC tube right through the wall can be decried by some experts, as they maintain it creates both a Thermal Bridge and a Damp Bridge too.

For myself, however, the clear benefits have outweighed any negatives.

Bonne courage !

 

[joidevie]

Many thanks..

I guess my next concern is what to do about the asbestos panels on the walls? They were mentioned in the buyer's report..?

[Gluestick]

Obtain separate estimates for their complete removal by a specialist.

Anything you do (Drilling holes) could compromise your health.

All depends what type of asbestos it is really: and how much asbestos was used in the composition.

There was another recent thread about this topic: only days ago.