Damp in 300 year stone cottage

[Rachaelf]

Hi, I have an old stone cottage (1667) with extremely thick stone walls (approximately 20 inches). It is a mid terrace. We think it was originally a barn covered into houses (many many years ago).

The issue I am having is downstairs around my chimney and most walls there is damp which is slowly getting worse. I use a dehumidifier for a few hours most days when I'm home.

Can anyone recommend the best way to treat the damp? The cottage is level with the ground. In some places it's like there are salt deposits coming off the wall which flakes the paint off and in others it's crumbling. I'm worried about getting a modern damp course and the walls not being able to breathe and it possibly getting worse. Has anyone had anything similar and what worked for them?

 

[Stevers]

20" is about right for external stone walls, 12" for stone internal walls. Looks like some damp proofing wallies have been there already - with predictable results.

 

[Rachaelf]

The wall I measured was originally an external wall, the house has been extended so the internal walls are probably not as thick. It hasn't previously had any damp proofing.

 

[aockenden]

I see a lot of cement. Cement pointing externally, cement render internally. Terrible for an old stone house. Remove it and replace with lime. Start with the places that are most damp. That pic with the heavily oxidized green copper pipe sticking out of the internal cement render is especially telling.

 

[Stevers]

The rusty corner bead, the big chunks coming away and all the salts. It may not have had the injected DPC, but it all looks horribly familiar to those of us that have been had. Also of course very typical of late 20th Century 'renovation' work.

 

[a twig]

Look up “Zebcolm” trench as well on here for a potential solution for your ground levels