What is Waterproofing?
Waterproofing in buildings is the formation of an impervious barrier over surfaces of foundations, roofs, walls and other structural members of building to prevent water penetrations through these surfaces. The building surfaces are made water-resistant and sometimes waterproof.
Commonly used materials for waterproofing in building is cementitious material, bituminous material, liquid waterproofing membrane and polyurethane liquid membrane etc.
Waterproofing in buildings and structures are generally required for basement of structure, walls, bathrooms and kitchen, balconies, decks, terrace or roofs, green roofs, water tanks and swimming pools etc.
7 Simple Steps to Waterproofing Exterior Walls
When exterior walls are exposed to rainwater or high humidity, water and moisture can travel through the masonry and affect your internal walls. This means that your walls may stay damp for a long time before drying, which may lead to mold growth and irreparable damage. In humid areas like Florida, wall damage due to water penetration isn’t a matter of IF, but a matter of WHEN.
How can you prevent water and mold from affecting your walls? By following the next seven:
- Check walls for faults:
Waterproofing external walls is the best solution only if the walls become damp as a result of rainwater or moisture. Before shopping around for waterproofing products, it’s important to eliminate any other causes of structural dampness. It could be anything, from cracks in your bricks or condensation within the wall to a burst water pipe. Once you fix the issue, you can apply a waterproofer as a preventative measure.
- Clean your gutters:
The problem with clogged gutters isn’t only that they may flow over the edge, down your walls; they also retain rainwater, which is gradually absorbed by the roof’s wood or fascia boards, potentially leading to a series of problems, including rotten wood, leaks, and mold. You can avoid all these and keep your home healthy by simply cleaning your gutters twice a year.
- Select the right waterproofer :
A series of waterproofing products are available today to help homeowners protect their homes from external moisture. Here are a few products you should consider:
- concrete waterproofing coating, which is a cement-like product that adheres to concrete and masonry permanently; it can be applied to any surface, including painted walls;
- silicate-based concrete sealer, which reacts with the ingredients in masonry and
concrete to form a waterproofing coating; this sealer can only be used on unsealed/unpainted walls;
- waterproofing paint, which is similar to acrylic wall paint, with the main difference that it delivers better waterproofing performance. It’s very important to choose a breathable formulation that is especially designed to allow walls to breathe and eliminate moisture. The product can be applied to surfaces previously painted.
- Use plaster waterproofing additive:
Plastering can help improve aesthetics, make walls more solid, and protect them against moisture ingress. Though most exterior plasters have waterproofing characteristics, you can eliminate water infiltration problems and prevent reoccurrence by simply adding a waterproofing admixture to the plaster.
- Prepare your walls for waterproofing:
Irrespective of the product chosen for waterproofing exterior walls, you have to bring your walls in good condition first. This means that you need to use a good-quality filler to repair cracks and patch holes. Allow the filler to dry optimally before grinding. Then sand away rough, uneven areas, remove dust by cleaning the surface with water, and let the walls dry completely to ensure a good adhesion between the waterproofer and the substrate.
- Apply the waterproofer:
You can use a roller or a brush to apply the waterproofer. If a second coat is required, allow the first coat to fully dry and then apply the second coat. Use enough product to create an impenetrable barrier against infiltration.
Conducting a water-tightness test is very important to evaluate the effectiveness of the products used for waterproofing exterior walls. For this test, water should be sprayed on the wall surface for a couple of hours, keeping the nozzle at a 30-degree angle. Your home will pass the test only if a moisture meter shows there is no moisture. By waterproofing exterior walls, you’ll not only prevent serious damage but also boost the value of your home.
Types of Waterproofing Methods for Buildings
TThe following waterproofing methods are commonly used in construction:
- Cementitious Waterproofing
- Liquid Waterproofing Membrane
- Bituminous Membrane
- Bituminous Coating
- Polyurethane Liquid Membrane
- Cementitious Waterproofing Method
Cementitious waterproofing is the easiest method of waterproofing in construction. The materials for cementitious waterproofing is easily available from suppliers of masonry products, and they’re easy to mix and apply.
This method is often used in the internal wet areas such as toilets. This method is usually a rigid or semi-flexible type waterproofing, but since it is used in internal areas such as toilets, it is not exposed to sunlight and weathering. Thus cementitious waterproofing does not go through contract and expansion process.
Applications of Cementitious Waterproofing
Cementitious waterproofing is used in the following type of structures:
- Water Treatment Plants
- Sewage Treatment Plants
- Railway & Subway Systems
- Marine Cargo Ports & Docks
- River Locks/Channels & Concrete Dykes
- Parking Structures & Lots
Liquid membrane is a thin coating which consists of usually a primer coat and two coats of top coats which are applied by spray, roller, or trowel. It offers more flexibility than the cementitious types of waterproofing.
The liquid cures into a rubbery coating on the wall. The elongation properties of the coating can reach as high as 280%. The durability of the waterproofing coating depends on what type of polymer the manufacturer use for the making of the liquid waterproofing.
Liquid waterproofing membrane can be of spray-applied liquid membrane composed of polymer-modified asphalt. Polyurethane liquid membranes in separate grades for trowel, roller, or spray are also available from various manufacturers.
Bituminous coating is a type of coating used for waterproofing and flexible protective coat in accordance with its formulation and polymerization grade. Its flexibility and protection against water can be influenced by the polymer grade as well as reinforcement of fiber.
Bituminous coating is also called as asphalt coating. The most common applications of bituminous coatings include areas that are beneath screed wet. It is an excellent protective coating and waterproofing agent, especially on surfaces such as concrete foundations.
Bituminous coating is made of bitumen based materials and it is not suitable for expose to sunlight. It becomes very brittle and fragile when long exposure to the sunlight unless it is modified with more flexible material such as polyurethane or acrylic based polymers.
The flexibility of the finished products always depends on the solid content of the polymer added to the bitumen.
Bituminous membrane waterproofing is a popular method used for low-sloped roofs due to their proven performance. Bituminous waterproofing membrane have torch on membrane and self-adhesive membrane.
Self-adhesive compounds comprise asphalt, polymers and filler; additionally, certain resins and oils may be added to improve adhesion characteristics. The self-adhesive type has low shelf life as bonding properties of the membrane reduces with time.
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.
Polyurethane liquid membrane method of waterproofing is used for the flat roof area and exposed to weathering. This waterproofing method is expensive.
Polyurethane Liquid Membrane 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 of membranes may happen after some time.