Choosing the right water proofing system is a complex problems and depends on case by case problems. Often Architects and Consultants ponder on this question as it requires great amount of prudence and experience to decide what kind of water proofing system is best suited when it comes to design stage and precise requirement of stopping the water leakages at that stage.
This is the most frequently ask questions when choosing types of waterproofing system to use. Often when comes to the design stage, most of the architect or consultant will ponder the question.
There are few types of the most commonly use system of waterproofing in the construction industry. They are :
1. Cementitious waterproofing
Cementitious waterproofing is often used in the internal wet areas such as toilets. Most of the time the type of cementitious waterproofing is semi-flexible, some even toward rigid type. It is still good to use because internal toilets are not exposed to sunlight and weathering and so it do not go through the contraction and expansion process continuously.
2. Liquid waterproofing membrane
Liquid membrane is a thin coating which consists of usually a primer coat and two coats of top coats. It offer more flexibility than the cementitious types of waterproofing. The elongation properties of the coating can reach as high as 280%. But the durability of the waterproofing coating also depend on what type of polymer the manufacturer use for the making of the liquid waterproofing.
3. Bituminous coating
Bituminous waterproofing coating is made of bitumen based materials and it is not suitable for expose to sunlight. It become very brittle and fragile when long exposure to the sunlight unless it is modified with more flexible material such as polyurethane or arcylic based polymers. The flexibility of the finished products always depend on the solid content of the polymer added to the bitumen.
4. Bituminous membrane
Bituminous waterproofing membrane have torch on membrane and self adhesive membrane. Torch on membrane is the more preferred one use because of its shelf life and ease of use during application.
The self adhesive type must be use fast as the bonding properties of the membrane is reducing through time. Very often applicators find the self adhesion membrane already lose its bonding properties when they want to apply. therefore, they have to use one additional primer to prevent the de-bonding problem in the near future.
Torch on membrane have exposed and covered types. Exposed membrane often has mineral granular aggregate to withstand the wear and tear of the weathering and the other types of membrane, contractor need to apply one protective screed to prevent the puncture of the membrane.
But one has to be very careful when applying the protective screed which is often cement mortar. The cement ratio has to be high and the mixing has to be thorough throughout the process. There are premixed types of cement mortar in the market available for use for better quality and consistency. Site mix usually will compensate the quality of the finish work but the cost is always cheaper compared to premixed mortar.
5. Polyurethane liquid membrane
Polyurethane is also use for the flat roof area and exposed to weathering but it is expensive. It can offer higher flexibility. Polyurethane is very sensitive to moisture content present, therefore before application, one has to be very careful evaluating the moisture content of the concrete slab. Otherwise peeling or de-bonding easily observed after some time.