Rising Damp Sydney. Sub floor fans destroy a house in Sydney!

www.RisingDamp.Sydney
This is a house in Sydney which we were called to for a rising damp quote and there was a wall on the external of the house which was bulging out by about 40mm. As a result we went under the floor to see what was going on. See the video above.
Eight years earlier the client had sub-floor fans installed in the front room of the house (no other rooms had sub-floor fans installed) and the above video is what we found.
Lets look at the mechanics of rising damp.
• Water
Rising damp is most often happens when the damp course that was installed at the time of construction fails in some way, allowing water to pass higher in the walls via capillary action to an evaporation point, usually 30cm - 1M above the floors in your house.
• Salt
The damage from rising damp is not so much the water but the salt that comes with the water. When water is in the earth it dissolves the minerals (salts) in the soil and transports them as the water seeps through soil and porous building structures.
As this salty water dries, the water evaporates into the atmosphere and the salt stays behind and crystalises at the surface in the pores of the bricks and mortar.
• "Entropy"
The scientific explanation is “a hypothetical tendency for the universe to attain a state of maximum homogeneity in which all matter is at a uniform temperature“.
An example is when you put an ice cube in a glass of water. The heat energy from the water will warm the ice, this heat energy from the water is transferred to the ice and as the ice warms it melts. In the end the water from the ice and the water from the glass are the same temperature.
..Lets change this logic to apply to the masonry walls of a building.
The tendency for water to attain a maximum state of homogeneity (equal saturation) until all bricks are at a uniform level of water saturation. In other words if there is a dry brick next to the wet brick the water will seep from the wet brick to the dry one until both bricks have the same water and salt content.
• Evaporation.
Nature always follows the path of least resistance and water will rise in a wall until it arrives at a point where it evaporates. This is usually above your floor inside your house which is why the paint and render often look damaged above floor level.
Installing sub floor fans only lowers the evaporation point to below your floors and because there is a much higher level of evaporation caused by the fans, there is an increased volume of salt water being sucked from the soil below into your bricks and mortar, but you can’t see it because it is hidden below your floors.
• Rapid Deterioration.
As the salty water enters the bricks and mortar of your house it collects inside the pores of the bricks and mortar. The sub floor ventilation fans increase the evaporation from the sub-floor walls and piers causing the salts to crystalise and grow. This applies pressure to the internal bonds which hold your bricks and mortar together.
Speeding up the drying process will cause more salty water will rise to replace the water that has evaporated. This will deposit more salt crystals inside the pores of your bricks and mortar until a tipping point is reached and the growing force from the salt crystals break all the bonds within the bricks and mortar of the walls and piers that support your building.
• Conclusion.
In short. Sub floor fans give the appearance of curing rising damp, but they just lower the problem to a place where you can’t see it (below your floors).
If you have mould in your house then sub floor fans can work wonders, but you need to be sure that the foundational structures of your house are protected and are at no risk of accelerated deterioration before you install them.
Contact the Rising Damp Specialists Sydney

[@dancooke5042]

What is the best way to get rid of the damp soil to avoid mould, termites etc without causing damage to the bricks?

[@risingdamp]

You can put a mortar or render on the surface of the bricks to act as a sacrificial layer. Fans don't always damage the bricks but it's a good idea if you install them to check the bricks under your house once a year for deterioration. If you see any deterioration you can apply some mortar or render to those areas at 5mm in thickness. It will need to be topped up from time to time if the salt damages the render you apply.

[@juzaus300]

Nightmare