Pros and cons of using bitumen for waterproofing the foundation, the types of mastic and the rules for its selection, the technology of applying a protective coating. Basement waterproofing with bitumen is the protection of the base with a strong and effective mastic that creates a seamless waterproof film on the surface. Manufacturers have developed many modifications of the material for use in a variety of conditions. We will talk about the choice of means and technology for applying on the walls in our article.
Features of waterproofing the foundation with bitumen
The foundation is a complex structure made of concrete and reinforcement that carries a large load. By its structure, it is heterogeneous; the monolith has pores and microcracks through which water will sooner or later reach the metal frame. Over time, corrosion will weaken the structure, which can lead to cracks and displacement of floor slabs.
One of the options for protecting the base from water is treatment with bitumen or bitumen mastic. The composition of the product also includes a solvent, modifiers, sometimes antiseptics and herbicides. The viscous material reliably clogs all micro-voids in concrete, brick, wood.
For waterproofing, solid raw materials are melted on fire, and the pasty mass is diluted to the desired consistency with solvents. The substance is applied to the wall from the water pressure side. It can be used alone or as an interlayer between the partition and the roll material.
Lubricating bitumen waterproofing of the foundation is used to protect against capillary moisture in draining and low-moisture soils, in which the water is 1, 5-2 m deeper than the basement floor level.
Resin is a flammable material, so be sure to follow the safety precautions. Basic requirements: work with resin in closed clothing, glasses and a respirator. Do not do anything in the rain and snow.
Advantages and disadvantages of waterproofing the foundation with bitumen
Coating a foundation with resin is the most common water protection option. We can highlight the main positive qualities that the base acquires after processing:
- A moisture-impermeable film forms on the outside.
- Mold and mildew do not grow on the surface.
- The substance clogs pores and minor damage to the wall.
- The film retains its elasticity throughout the entire service life and does not lose its properties in the temperature range from +100 to -50 degrees.
- The insulator is easy to apply to the wall, you don't need to hire professionals and save money.
- The low cost of raw materials allows people with any income to buy it.
The owners of the house should be aware of the possible troubles that sometimes arise in the case of bituminous waterproofing of the foundation:
- After the house has shrunk, tears sometimes appear in the material.
- The resin protects the wall for 10 years, then the procedure must be repeated.
- The work is done more slowly than by other means.
Basement waterproofing technology with bitumen
The creation of a protective coating takes place in several stages. First, you need to select the type of material and determine its quantity. Then the base is prepared and the solution is applied.
Selection of materials for foundation protection
To form a protective layer, it is necessary to purchase not only bitumen, you will also need a primer for treating the base. A brief description of the most popular remedies is given below.
Lubricants are divided into two types - bitumen and bitumen mastic. The first type includes solid products of the BN-3, BN-4, BN-5 brands. Most often they are applied to horizontal areas and to places where a thick layer is needed. Can be used as stand-alone insulators or in combination with other resin-based substances.
Bitumen for waterproofing the foundation before work is heated to a temperature of + 160-180 degrees, which requires the presence of heating devices on the construction site. A high temperature is required to completely remove moisture from the substance. The material is distinguished by its low price per square meter. Often there are various additives in the composition to increase elasticity.
The mastic is made with organic solvents and applied cold. These tools include:
- Conventional solvent-borne bitumen mastic … The most popular base waterproofing agent. It stands out for its low cost, but the durability of the protective film is small.
- Bituminous mastic with the addition of polymers … It increases elasticity, improves adhesion to the substrate, and increases the temperature range of use. Does not require complete drying of the wall. The cost of the material is high, so it is used in exceptional cases. Of the minuses, it can be noted that it cannot be used in places where water is constantly present.
- Water-based bituminous mastic … Designed to be applied to basement-side surfaces. It is used if it is impossible to process the walls from the outside. It is water-based and therefore odorless. Safe in confined spaces. The substance has temperature limitations - the temperature in the basement must be +5 degrees or more.
- Rubber-bitumen mastic … It is used to obtain a high quality coating. Reliably protects the wall even under water.
- Bituminous-latex emulsion … The walls of a large area are covered with it in a mechanized way. Up to 1000 m can be processed in 8 hours2.
- Two-component bituminous mastics … Individual elements of the substance are sold in different banks and are combined before work. The product has a long shelf life and quick hardening.
- Hot mastic … Not afraid of difficult climatic conditions. To liquefy it, it is heated to a temperature of 300 degrees.
To improve adhesion to the resin, the surface is primed with a primer. It is a special mixture designed for a specific type of insulator. Sold in a liquid ready-to-use state. The declared characteristics of the product at home cannot be checked, the quality of the product can be judged only by indirect signs. For example, a five-liter bucket of a substance cannot weigh more than 5 kg, because the primer is lighter than water. If the container is heavier, there are foreign additives in the mixture.
The primer can be prepared independently from BN70 / 90 or BN90 / 10 bitumen and a solvent (gasoline, kerosene), in a ratio of 1: 3 or 1: 4 by weight. Another option is to use for these purposes a mastic with a heat resistance above 80 degrees, diluted to a semi-liquid state. The type of primer must match the waterproofing agent.
The consumption of bitumen mastic depends on many factors: the area of the treated area, the density of the resin, its brand, composition and quality. To determine the volume, you can use our recommendations:
- 1 m2 the vertical surface goes from 300 to 900 g.
- For horizontal sections, 1-2 kg are used per 1 m2.
- The thickness of the insulation depends on the depth of the foundation. If the base goes down 0-3 m, it should be at least 2 mm, if 3-5 m - 2-4 mm.
To minimize the consumption of bitumen when waterproofing the foundation, periodically check the thickness of the layer. If it is decided to smear the wall only twice, apply 1.5 mm at a time, if four - 1 mm each. Measure wet and dry film thickness.
For control, use universal thickness gauges or improvised means. For example, a comb helps if the solution is still liquid. To determine the size of the dried substance, cut a small segment of film from the wall and use a caliper. If the parameter does not correspond to the permissible value, re-process the baffle.
Not all bitumen-based products can be applied to the foundation. Do not use products made of liquefied material due to low operational durability.
Foundation surface preparation
Waterproofing can be carried out at any stage of construction. It is easier to complete the work at the stage of building a building, when the base has not yet been covered with soil.
If the house is residential, outside, next to the foundation, dig a trench to its full depth. For convenience, the width of the pit should be at least 1 m.
Then follow these steps:
- Inspect the structure for defects and determine how to fix them. The wall must be solid, without breaks.
- At the junctions of horizontal and vertical planes, make fillets for smooth mating of surfaces.
- Expand cracks to a solid base and seal up with cement mortar.
- If you find a large number of sinks, rub them with a special fine-grained cement mortar. The operation is carried out to exclude the appearance of air bubbles when applying the mastic.
- Remove sharp and sharp protrusions and combs from the wall or round off with a radius of 3-5 cm. Otherwise, after filling with soil, damage to the coating will occur. To eliminate the shortcomings, use a grinder with suitable attachments. The tool will also be needed to round the corners of the structure.
- Clean the wall from dust and dirt.
- Make sure the surface is dry. The presence of moisture can be determined using special devices. The permissible value is no more than 4%. If there is no moisture meter, cover a section of the wall with plastic wrap and leave it for a day. If a wet spot appears underneath, the wall is not ready for waterproofing. You can dry the partition with a construction hairdryer.
- If the groundwater near the house is close to the surface, install a drainage system. It will reduce the hydrostatic pressure on the structure.
Preparation of bitumen for application to the foundation
The substance is diluted or melted to a semi-liquid state, convenient for work. The preparation process depends on the type of material.
Solid bitumen is melted on fire in any container - bucket, tank, iron barrel, their size depends on the area to be treated. Pour pieces of resin into the barrel, light a fire under it. After melting, the raw material is ready for use. It will take 2 people to work. The stoker maintains combustion under the tank and makes sure that the solution does not run out. The second performer is working on the wall.
Bitumen-polymer mastic liquefies without heating. Grind the resin, put it in a container and fill it with a solvent - gasoline, kerosene or white spirit. Stir the contents until a jelly-like mass is obtained. When working, observe the fire safety rules due to flammable gasoline fumes.
The two-component mastic is sold in two containers. One contains bitumen, the other contains polymer additives. To prepare the solution, combine both elements and mix for 5 minutes with a low-speed drill with a special spiral nozzle.
Instructions for applying bitumen mastic
The process of applying the solution to the wall is simple, but the operations are performed in a specific sequence:
- Prime the surface with primer or other means with a brush in one layer. Areas covered with cement-sand plaster - in two. The following work can only be carried out after the walls are completely dry.
- Pour the prepared bitumen into a bucket and take it to the house.
- Fill a small container with the solution, dip a wide brush or paintbrush into it, and slide it down the wall. Perform the next strip with an overlap on the first.
- If the waterproofing is done in a hot way, it is necessary to work quickly, because in a small container the solution begins to solidify after 1-2 minutes. On the wall, the resin completely freezes within 24 hours
- The two-component mastic will last for 30 minutes, so use it quickly.
- Reinforce bitumen with reinforced material in cracked wall areas or near cold joints. For these purposes, fiberglass fabric, fiberglass or geotextiles with a density of 100 to 150 g / m2 are suitable.2… Apply a layer of substance to the wall, apply fiberglass to it and press firmly with a roller to the base. The canvas must cover the problem area and the area around it by at least 100 mm. There should be no voids under the strip. The use of reinforcement will distribute the tensile load over a large area, reduce the pressure on the foundation near the crack, which will extend the reliability and durability of the structure.
- After the first coat has dried, apply the next one. The solution is considered to be hardened when it stops sticking. The solidification time depends on many factors - the composition of the mixture, temperature and humidity, usually lasts 4-6 hours. It is recommended to resume work after 24 hours.
- After the wall has dried, fill the trench with clean sand without foreign matter that can damage the coating.
How to apply bituminous mastic to the foundation - watch the video:
Bitumen is the most affordable and popular material for waterproofing foundations. It is easy to apply, which allows you to do the operation yourself. It is only important to follow some simple rules for working with this substance.
