HYGROSCOPIC SALTS are a particularly complex, frustrating and damaging aspect of traditional building ownership.
Often mis-diagnosed as either a leak, rising damp or simple condensation, Hygroscopic Salts often present themselves as damp patches on the walls, especially areas surrounding, and above, old fireplaces and chimney breasts, but can also appear elsewhere.
They can be caused by many years of open fire-burning, where the accumulated deposits soak into the masonry. They can also be caused by continuous damp e.g. a leaking gutter and once fixed the wall now displays this ongoing issue. Equally, cement renders & pointing can physically introduce salts into the wall or cause a wall to remain damp and begin to exhibit this phenomenon.
Likewise, Cement Slabs poured over old floors or DPMs, can cause huge salt accumulation underneath which can then be absorbed into the base of the walls and travel upwards via rising damp to add more misery to an age old issue.
The visual effects of these Hygroscopic Salts can come and go with rising and falling humidity levels which, since this often coincides with rain fall, can further serve to confuse whether the issue is the result of a leak or not.
Deliquescent Salt describes the action whereby Hygroscopic Salts absorb enough moisture in order to cause themselves to melt into a briny solution i.e.e Deliquesce and this liquid state then allows the salts to travel further and deeper into the masonry
Efflorescence describes salts and minerals which have risen to the surface of the brickwork and accumulated as the moisture eventually evaporates.
However, an even more serious issue can be apparent in the form of Crypto-florescence, whereby the deliquescent salts which are present, or have now been absorbed, deep into the pore structure of the masonry then begin to dry out and crystallise with very damaging results.
This action of crystallisation of the salts literally forces the masonry units apart from the inside and they can crack and crumble which can have devastating effect on the brick and stonework.
The beauty of Lime Plaster and Lime Pointing is that it allows the salt laden moisture to reach the surface and evaporate which can help alleviate these issues but the ugly nature of damp spots and salts on the surface of the plaster can be bothersome for many people.
The above issues can be a very difficult issue to resolve short of replacing all affected masonry and plasterwork, which can at best be messy & disruptive and at worst be almost impossible & extremely expensive.
However it can have many benefits in that it removes the damaging salts and can prolong the lifespan of a building and the quality of life for it’s inhabitants.
The issue with using salt-neutralisers is they require the user to soak the wall with a water based solution.
This can not only drive the salts further into the masonry but is not a very practical option when spraying a lot of water inside a house which can then irreversibly damage the property, soft furnishings, etc etc
We have therefore developed our own sacrificial Poultice which can be applied like a plaster to bare walls and used to help draw the salts out of the affected masonry units.
This poultice can then be easily hacked off and discarded taking the salts along with it, leaving the wall ready for re-application of fresh lime plaster, and, hopefully, a reduction in the Salt related issues.
