Salt damp is attacking Adelaide’s built heritage
However it’s also found during many of the building inspections we conduct on the standard brick veneer homes across South Australia.
Salt damp and rising damp are two different things but they need to be attacked in a coordinated manner by home owners and people maintaining and renovating properties.
‘Salt damp’ is a term in common use across Adelaide but it essentially is referring to the high concentration of salt associated with rising damp. The high concentration is both a symptom of rising damp but it complicates the problem as the high concentrations of salt act to more quickly deteriorate the brick work, mortar and render.
How does Salt Damp occur?
Salt damp occurs mostly in older buildings across Adelaide where modern damp proof courses were never installed. Or if some kind of damp proof course was installed, it’s now been damaged or deteriorated to allow the water in the soil to be sucked up into the brick work, block work or render by capillary action.
This water has an amount of salt in it and when as it rises up the walls, so does the salt. The water will eventually evaporate and dry out but the salt remains as crystals on the surface and within the cracks of the mortar. It accumulates over time and attacks the brick work, its mortar and rendered finishes.
How does Salt Damp damage buildings?
Salt Damp damage goes beyond un-slightly white deposits. Over time salt crystals are forming in the mortar of brick and block work, they rest on the surface of rendered finishes and they find their way into every nook and cranny of a built structure. The salt will disrupt the masonry.
This will cause decay and fretting of the masonry skin. The brick itself will begin to crumble and the mortar will become dusty and erode more quickly than ever intended.
Why does so much Salt Damp occur in Adelaide?
Our building inspectors across Adelaide are constantly identifying and reporting on Salt Damp. This is because Adelaide has very salty soils which when combined with the hot drying summers make it more susceptible to salt damp than other major cities. To contact one of our Adelaide Inspections, or to read more about SA building inspections and highlights in the Adelaide area, visit our Jim’s Building Inspections Adelaide page.
Seven Steps to Fix Salt Damp:
- Once salt concentrations have reached a level where there are visible salt deposits you have to tackle both the salt and the damp. Trying to treat just one or the other will no longer work.
- Diagnose the cause of the Damp
What is the cause of the damp? Is the damp moving up, down or across the wall? - Dry out the Damp
Whatever the cause attack it at its source, this may involve clearing and cleaning out gutters, moving soil away form the base of walls, replumbing some of your storm water or changing the site drainage. - Treat mild damp
Once you have removed the cause of the damp treat existing weak and eroded mortar, plaster and bricks as the sacrificial lamb. Even with the source damp removed, there is likely to be remant excess moisture in your walls. You need to leave it to dry out and the existing building materials will suffer. After some time – maybe a whole summer – you can then clean it out and replace it once you know the damp problem is gone. - Remove excess salt
In the meantime you can remove excess salt – not by washing but by brooming, brushing and vacuuming it off (vacuum if it’s a heritage building or you don’t want to make the brick damage worse). - Review results
This process may take a year or more to resolve, you are likely to need to run a full winter to make sure you have dealt with preventing the damp from recurring. This will reveal if you have done enough or need to go further to protect the building. This is when you need to look at a structural intervention. - Insert a Damp Proof Course (DPC)
There are a couple of options here including an injectable or chemical damp proof course or something called undersetting or cutting out a section of the wall to insert a new damp proof course. - Desalinate the walls
In conjunction with inserting a DPC you need to also desalinate the walls, there are a range of sacrificial plasters and something called captive head washing to deal with the salt already in situ.
If you have concerns about salt damp around your home in Adelaide call our local Building Inspectors on 131 546 and they can assist you to identify the cause of the damp and put an action plan in place.
For more information on Salt Damp CLICK HERE to read what the Adelaide City Council has to say.
Source:
Title: Salt attack and Rising Damp, A guide to salt damp in historic and older buildings
Author: David Young for: Heritage Council of NSW- Heritage Victoria- South Australian Department for Environment and Heritage- Adelaide City Council
Link: http://www.adelaidecitycouncil.com/assets/acc/Development/heritage/docs/salt_attack_rising_damp_technical_guide.pdf
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