Rising damp is unfortunately a common problem detected when undertaking building inspections in Brisbane. These particular photos were taken of a house in Mount Gravatt during a pre-purchase building inspection. Rising damp generally occurs where the damp course barrier laid within the wall has not been correctly installed or in older buildings, may not have been installed at all.
One of the tell-tale signs of rising damp is a white powder emerging on the face of the wall known as a efflorescence. This is the salts and minerals being brought through the face of the wall during the rising damp process. A moisture meter test on these walls will usually give a high moisture meter reading.
One of the most detrimental effects of rising damp is what is commonly known as brickwork fretting. This is where the face of the brickwork literally crumbles and disintegrates, eventually structurally damaging the bricks. If left unaddressed, walls could eventually collapse.
In habitable living spaces, internal rising damp can prove to be a health issue particularly for people with asthmatic conditions.
If you have a rising damp issue it is possible to undertake remedial works to prevent further deterioration. Traditionally a new damp course barrier was literally cut into the bottom portion of the brickwork to prevent rising damp occurring. These days a much simpler and very effective injection method is utilised. A small hole is drilled at every intersection of the bricks approximately 150 mm above ground level. The small holes are subsequently cleaned prior to a liquid or thick cream membrane being injected into the drill holes. This membrane subsequently disperses through the mortar joint and brickwork forming a waterproof barrier preventing further rising damp. A product I have personally used in the past is from a company called “Tech-dry”. If applied correctly this injected method is very effective at preventing further rising damp issues.
If you are trying to prevent moisture passing through a wall that is well below ground level, this involves an entirely different rectification process. This usually involves the installation of tanking barriers and drainage behind the wall. In general terms a tanking barrier is a waterproof membrane adhered to the face of the wall. Combined with adequate drainage, moisture can be prevented from entering into a wall. In some situations this can however be cost prohibitive to retro install. In these situations, although not ideal, waterproof membrane systems could potentially be placed on the inside of the wall. This is however not always effective depending on the level of moisture penetration and this method has limitations.
Contact Action Property Inspections if you require further information regarding rising damp or for any independent Brisbane building inspections or construction issues.