What is foundation waterproofing membrane?
A relatively thin layer of material placed on either external or internal face of a structure that will provide resistance to the passage of moisture inside the structure is called a Waterproofing membrane. The waterproofing membrane applied at the foundation to resistance to the passage of moisture is known as the foundation waterproofing membrane.
Why should the waterproofing membrane be applied in the Foundations?
The waterproofing membrane is made to restrict the water to enter the structure. Because when water enters the structure either in foundation or basem*nt or terrace, it causes dampness.
Dampness further affects the strength of the structure resulting in a prominent decrease in the load-bearing capacity. If this is not treated well, it can also result in the settlement of the structure causing a huge loss of lives and property.
Furthermore, dampness also causes asthma and breathing-related problems to people and is not aesthetically pleasing.
Application of waterproofing membrane
Waterproofing can be done in different parts of the structure such as terrace, basem*nt, toilets, balconies, concrete water tanks, swimming pools, gutters, and so on.
Materials for waterproofing membrane
- Polythene sheeting
- Epoxy resin compound
- Bituminous compound
- Mastic asphalt
- Bituminous felt
- Bitumen laminates
- Cementitious high build coating
- Fiberglass
- Bentonite clay
- Elastomers and so on.
How long does it take to dry the waterproofing membrane?
It normally takes 24 to 72 hours. Different factors like temperature, the porosity of substrates, relative humidity, and airflow determine how much time it requires for drying and curing.
Different Types of waterproofing membrane
Cementitious waterproofing
This type of waterproofing relies on the use of cement. It is mostly used in basem*nts and crawl spaces. If used right, it serves is the purpose with the best results.
Crystalline waterproofing
This type of waterproofing makes use of silicon-based crystalline to waterproof the structure. It is an effective and economic way of waterproofing.
Sheet based waterproofing membrane
These membranes are like sheets that are rolled. We can use this type of membrane by unfurling the sheet and placing it on the firm surface. This type of membrane is stacked with the surface using hot tar and blowtorches. They have joints.
They are of two types: self-adhering membranes and non-adhesive sheet membrane.
Liquid applied waterproofing membrane
This type of membrane comes in liquid form. It is either sprayed on the top of the surface of the structure or applied with the help of a brush. They are joint-free and has easy application so can be done in a large area at once.
They are also of two types: cold fluid-applied membranes and hot-applied systems.
Built-up or laminate membrane
It consists of thick tar or contentious compound topped on the surface of the structure.
Injectable waterproofing
This type of waterproofing is done in the existing structure. While performing this type of waterproofing, a hole is drilled in the structure, and chemicals or adhesives are pumped through it.
Asphalt tanking
This type of waterproofing is used to provide a continuous waterproofing membrane to the base and walls of the basem*nt.
How to select a waterproofing membrane?
This depends upon different properties of the material:
UV resistance: the membrane applied should be UV resistant, otherwise it will degrade over time if exposed to the Sun.
Tear resistance: The membrane should not tear even if a strong force is applied in it.
Abrasion resistance: The membrane while in the construction phase should be able to resist wear and tear caused due to workers walking over the membrane, screws and nails dropped on the membrane, and so on.
Chemical stability: The membrane should not react with different chemicals if exposed.
Elongation: Elongation is a must property of the membrane to be used as it can fill up the cracks and voids that may occur in the future.
how to install foundation waterproofing membrane?
First of all, we should select what type of waterproofing membrane we want for our foundation. After selecting the type of membrane, we should first apply the membrane in the cold joints because they are the most critical parts in the foundation. Then, it is applied in the rest parts of the foundations.
Where to use waterproofing liquid membranes and Sheet membranes?
It depends on the situation of the construction site as well as the time. When you need a smooth surface quickly then you can use sheet waterproof membrane.
Because the sheet has a uniform shape made by machine and you will get a uniform thickness. So you don’t have any risk that there could be any differences between the film thickness of the membrane.
But, if you have enough time and less budget then, you can go through a liquid waterproof membrane.
If there are small hairline cracks in the structure like slab, wall, etc then it would be better to use sheet waterproof membrane.
Conclusion
There is different waterproofing membrane available in the market. We can select the membrane as per our needs and environmental factors. Waterproofing membrane can last up to 10 years depending upon the type of material used and workmanship.
I hope this post remains helpful for you.
Happy Learning – Civil Concept
Contributed by,
Civil Engineer – Sushmita Niraula
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