Salts are naturally present in the earth, and we need certain salts for our survival.
But there's two types which are not good to your house: Hygroscopic & Efflorescent salts.
Hygroscopic salts absorb and effectively 'kidnap' water/moisture; they can cause dampness, cold and decay in masonry structures.
Common table salt (sodium chloride) is a hygroscopic salt which we, as humans, need - But leave an open pot of it on your kitchen worktop and check back on it a month later to see how much atmospheric moisture it has absorbed.
On the other hand, whilst Efflorescent salts do not necessarily absorb water/moisture they will still hitch a free ride along with water/moisture via capillary action, but they will leave (release) that water/moisture to evaporate off into the atmosphere.
These efflorescent salts are the ones which leave white, powdery deposits; a defect known as 'efflorescence', on the surfaces of internal plaster, and external brick and stonework, indicating salt damage.
The noticeable presence of either of these two is down to one common issue: excess moisture.
If left untreated, salts, especially hygroscopic salts trapped within the walling can weaken the structure of period buildings, predominantly through salt hydrolysis which can compromise the structure of a building's integrity over time.
Hydrolysis refers to the reaction of the cation, the anion, or salt ions with water, resulting in an acidic or basic solution. It is the reverse of neutralisation. The extent of hydrolysis depends on the strength of the acid and base from which the salt is derived, plus if this solution comes into contact with bricks containing natural iron oxides this can cause what's termed an 'insoluble compound'.
Heres one of our vids showing some earth salts across the foundations of an Edwardian Building:
The Importance of correct treatment
Yet again, "Find the cause, Fix the cause"
The cause is excess moisture which transports these salts through capillary action.
As that water/moisture reaches both internal & external wall surfaces; such as internal plaster/external brickwork/render it then wants to evaporate naturally into the internal/external atmosphere, Efflorescent salts let it go, leaving the salts behind as white 'powdery staining' on the surface.
However, hygroscopic salts are quite different: they are still transported in solution via capillary action through building elements but because they won't release that moisture, instead they put up a fight and form permanent areas of dampness trapped within the fabric of your walls.
Simply put: damp walls are cold walls, and they can freeze internally during winter months.
When water freezes it expands by 9% in volume - so you don't really want them flexing their muscles and eroding your walls from inside out!
With our expertise we can help you to protect your building for years to come.
Dealing with efflorescent salts is fairly simple.
'Efflorecence' is a common salts defect which is more unappealing aesthetically and often regarded as unsightly, generally more often seen after recent Building works or internal plasterwork repairs where unwashed sands have been used in the mixes.
But it's relatively easy to deal with:
First thing to do is to dry scrape and stiff brush all of the visible salt affected areas, this will allow more moisture to escape.
You will most likely see more salt deposits on the walls as more moisture reaches the surface & evaporates; efflorescent salts are quite harmless and just need brushing/vacuuming off with a brush attachment from time to time).
Do not listen to anyone advising any of these;
Salt neutraliser
Brick acid
Bleach
Anything "HG"
In fact do not use any form of liquids whatsoever because all you will do is re-dilute those salts back into a solution which will be transported back into the walling through absorption.
That solution will then travel back to the surface again carrying the salts, and you'll simply end up on the "salt merry-go-round"
Simply dry bush/vacuum each time they reappear, until the moisture stops evaporating from the walling and the salts stop appearing.
Avoid Tanking! - Hygroscopic salts are a bit different.
The Damp specialists love to tank cellars, but given that cellars are usually subterranean spaces so are surrounded by earth; earth which naturally contains hygroscopic salts, we've found many cases where the impermeable tanking, which blocks all air passage to & from the walls, forces any salts and moisture within those walls to simply travel higher through the walling via capillary action; resulting in the ground floor walling becoming damp and that dampness then trying to escape internally, drawn in by the warmer internal temperatures, and creating damage in living spaces where there never were any issues before.
Dealing with hygroscopic salts is a bit of a different matter; these can cause lots of issues when trapped inside walling, whilst retaining moisture; most bricks contain iron oxides which adds to the hygroscopic salts solution to form an 'insoluble compound'
Removal of these can be quite time consuming, so dealing with these often requires a lot of patience.
A visit from us to help determine your individual situation and formulating a plan for you to follow can help.
The photo below shows the result of hygroscopic salts having been driven up from the cellar walls after that cellar was tanked, and are now trapped in the walls of the ground floor lounge! A case of salts hydrolysis meeting red brickwork, adding iron oxides into the mix and becoming trapped within the fabric of the wall as an insoluble compound.
Whilst this photo may just at first appear to be unappealing aesthetically, the interior condition of this wall coupled with the low temperatures of this wall meant that aesthetics was the least of the homeowners concerns!
(Click the pic to enlarge)
Don't let salts damage your
beautiful period property.