For many real estate developers and homeowners, waterproofing is seen to be a costly undertaking
that is unnecessary, but other than fire, the next worst thing that can happen to your home is water
damage. We have all seen many houses flooding as a result of heavy downpour.
During construction, wet areas and areas prone to water exposure must be waterproofed to ensure that
the living areas remain unaffected by water and kept dry especially during the rainy seasons. It
also reduces humidity in the house, which can damage structural materials, furniture, fixings, floor
coverings and even affect health.
Your home is probably your most important asset that needs to be protected. A waterproofing
contractor will use membranes and other types of coatings and materials to protect the interior and
exterior of the house giving structural integrity and will protect the house both inside and out.
Waterproofing starts in the early stages of construction, from the foundations right up to the roof
top and landscaping.
Areas that need to be waterproofed:
Balconies / Decks
Terrace or Roofs
There are many benefits to waterproofing your house, which include;
Safety: Waterproofing will keep your family and possessions safe during cold and hot
is known to rot timber, cause concrete integrity issues, ruin furniture, floor finishes, fixings and
cause different kinds of illnesses if mould is present.
Preservation: Waterproofing will keep your house in good condition for a long period of
regardless of harsh weather conditions. This will also help keep the value of your
home.Waterproofing your house may be expensive, but the benefits far outweigh the cost. The damage
that is caused by water will cost tens of thousands of dollars to repair.
Types of waterproofing:
Negative or hydrostatic Pressure Membranes:
These products can be applied to damp surfaces from the inside of structures. They cannot stop
active leaks but can stop rising damp and hydrostatic water pressure. They are commonly used in
basements from the internal wall to stop water seepage. Common Negative pressure membranes include,
Hydrostatic Epoxies, Cementitious membranes & water reactive polyurethanes.
This is the easiest waterproofing method used in construction, because the materials used in
cementitious waterproofing are easily sourced from suppliers, and are easily mixed and applied.
It is used internally in areas that are normally wet. This is because it is a rigid type of
waterproofing that is also semi-flexible.
A liquid membrane provides a coating which is approximately 1.2mm thick and consists of two top
coats and a primer coat that are roller applied. It is more flexible than the cementitious method.
The liquid forms a coating which is of rubber-like consistency on the walls & floors that provides
an impervious coating. The two main liquid membranes used today are Water Based Acrylic membranes
and Solvent Based Polyurethanes.
This is a type of waterproofing method that provides a protective waterproofing coating in
accordance with the laid out polymerization and formulation grades.
It is also known as asphalt coating and the most common areas of application are below ground and
roof tops. It also provides an excellent protection on concrete foundations. This is because it is
made from bitumen materials which become fragile and brittle when exposed to sunlight.
Bituminous Sheet Membranes:
This is a method for low-sloped roofs that is very popular because of its proven performance. It is
applied as self-adhesive or torched on with a butane torch.
The self-adhesive comprises of polymers, asphalt, and filler. It may also contain some oils and
certain resins that improve the adhesion characteristic. It has a low shelf life because the
membranes bonding properties reduce with time.
Torch on membranes have covered and exposed types. The exposed membrane contains an aggregate called
mineral granular that withstands wear and tear r. The other types of membranes usually requires an
extra layer of protective screed to avoid puncture.
TPO or Thermoplastic Polymer Membranes:
This is mainly used on flat areas, such as rooftops as it can withstand extreme exposure to
weathering. It can also be used in internal wet areas, balconies and planter boxes. It is very
expensive and the costs usually double to triple the price of a liquid membrane system. The system
consists of modified polymer sheeting that is heat welded at the seams and has insitu pieces for
corners and floor wastes. It requires the most skill of all waterproofing types but is superior in
many ways. It is also convenient as it only requires one layer and usually the job can be completed
within a day.
This helps to seal up any large cracks or active water leakages. It hides any untidy marks, and
provides an aesthetically appealing coverage. It can be coated over with any negative pressure
This is one of the most superior waterproofing solutions. Crack injection is used for active water
leaks, usually below ground and is applied by drilling a port into the joint or crack and using a
high pressure pump to inject a water reactive polyurethane. The polyurethane reacts and expands into
the joint with contact of water and seals the leak instantly.
Spray Applied Polyurea Membrane:
Spray applied polyurea is one of the newest innovations in waterproofing.It requires little
preparation and large areas can be waterproofed in a small amount of time.Spray applied Polyurea is
very fast setting, easy to apply and extremely flexible and tough.It consists of a high pressure
pump fed from a large drum of solution and is applied via a wand, similar to a pressure washer.
It is important to waterproof your balcony correctly during the construction stage.
As mentioned earlier, there is a common misconception that waterproofing is not very important, but
when you think of the possible consequences if your waterproofing was to fail the damages far
outweigh the initial cost, prevention is better than cure. A house is constructed to last a
lifetime, and your waterproofing is a major contributing factor to it doing so.
The cost of waterproofing is typically 1% of your build cost yet is the most common defect in new
buildings. The average house will cost $2500 to waterproof whereas the cost to strip, re-waterproof
and refit just a single bathroom can easily reach the $15000 mark.
Protect your valuables,your home and your health by ensuring your waterproofing is carried out by a
qualified and experienced waterproofing contractor.