Waterproofing the foundation with plastic wrap

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Waterproofing the foundation with plastic wrap
Waterproofing the foundation with plastic wrap

Advantages and disadvantages of using polyethylene film for waterproofing the underground part of the house, types of material for such work and the rules for its selection, technology for laying the product. Waterproofing the foundation with a polyethylene film is the protection of underground structures from groundwater with a thin sheet material. This option is effective for small buildings as primary and secondary insulation. We will talk about the features of using the product in this article.

Features of the use of polyethylene film for waterproofing the foundation

Polyethylene film production

Plastic wrap is considered to be an inexpensive alternative to traditional wrapping materials. It is made on the basis of polyethylene with the addition of stabilizers, modifiers and dyes. It is sold in rolls with a maximum width of 6 m and a length of 50 m. It is sold in the form of a canvas, a sleeve, a half-sleeve. Retains its properties at temperatures from -50 to +60 degrees.

The product is mainly used for waterproofing horizontal surfaces, less often vertical ones, because it is difficult to secure it. The film is very popular in private construction. It is usually used in conjunction with another type of insulator to increase efficiency and safety in the event of ruptures, or with insulation to protect against moisture.

More reliable modified film waterproofing - membrane. It is more durable, but more expensive.

The product is laid on the wall on both sides. On the outside, it protects against groundwater, on the inside, it does not allow moisture to quickly evaporate when the concrete hardens.

Advantages and disadvantages of waterproofing the foundation with plastic wrap

Installation of polyethylene film

Polyethylene construction grades have characteristics that other models do not have. He is chosen for such qualities:

  • The material is absolutely impervious to water. In the basement, it can be used to vapor barrier the foundation walls from the inside.
  • It resists mold and mildew well.
  • The profiled surface prevents specimens from slipping during installation.
  • Does not rot or decompose for a long time.
  • Polyethylene is easy to fit - it is lightweight, elastic, wide. You can cover a large area with one sheet.
  • Adjacent cuts are easily connected with adhesive tape or a special welding machine.
  • Possesses high tensile strength.
  • Compared to other waterproofers, it is inexpensive.

The owner should also be aware of the problems that may arise while working with the film and during operation:

  • It is inconvenient to attach the material to vertical walls.
  • It can be easily damaged during installation and further operation, therefore, for protection, it is necessary to build an additional structure.
  • The coating quickly deteriorates when exposed to sunlight. The service life of the product in such conditions does not exceed 1 year.
  • Rodents can spoil the canvas.

Foundation waterproofing technology

Waterproofing takes place in several stages. First, you need to decide the issue with the brand of the product that is suitable for your case, then the base is prepared and the basic operations are performed.

The choice of plastic film

Polyethylene film for waterproofing

When buying an insulator, familiarize yourself with its parameters in advance and check the quality of the products. The waterproofing film for the foundation must be made of low-density polyethylene in accordance with GOST 10354-82 or high-density polyethylene in accordance with GOST 16338-85. Such an entry must be in the certificate of conformity that is supplied with the product.For work, purchase a product of the "T" brand, which has good elasticity.

The price of a film for waterproofing a foundation is significantly influenced by its thickness, so always pay attention to the surface density, measured in g / m2… This parameter is easy to verify and sellers do not run the risk of falsifying values. If there is no information, please contact another store.

A canvas with a thickness of 0.5 mm is considered universal; it is laid on vertical and horizontal surfaces. Sheets 0, 6-0, 8 mm are much stronger, but less elastic and are very expensive. Products 0, 06-0, 2 mm are placed on the floor.

There are several types of material - rolled plain, reinforced and diffusion membrane. Each type has its own purpose. Let's consider their characteristics in more detail:

  1. Roll film… For the completion of the foundation, polyethylene in rolls is most often purchased. Its cost is low, but its strength is low, so manufacturers have recently begun to add various components to the composition that increase strength.
  2. Reinforced film… Made from several layers. Inside there is a non-woven base or polypropylene mesh, outside there is a perforated or non-perforated coating. When buying, you need to pay attention to the density of the product, which should be in the range of 100-250 g / m2… Thickness does not play a special role.
  3. Diffusion membranes… They also consist of several layers, are expensive, but much stronger than standard film.

Before you buy a film for waterproofing the foundation, perform simple operations that will help identify poor-quality goods:

  1. Unwind the roll and inspect the product. The presence of cracks, pressed folds, holes, breaks is not allowed.
  2. Examine the ends of the roll. Offset of sheets is possible only by the amount of the tolerance for the width of the web.
  3. Check the presence of the label on which there is a conventional designation, brand, total length, date of manufacture, weight.
  4. Make sure that the material is stored in a covered warehouse in a horizontal position, at a temperature of +5 to +40 degrees, out of the reach of sunlight. The goods should be located at a distance of at least 1 m from heating devices. Please note that at temperatures below -30 degrees, it retains its properties for 30 days.
  5. Check the release date. The permissible shelf life is 10 years.

Polyethylene film for waterproofing the foundation is very similar to other similar materials - cellulose acetate (AC) and polypropylene (PP). In order not to be mistaken when buying, you need to know their distinctive features.

Pay attention to these points:

  1. Appearance: polyethylene film has a dull surface, other modifications have a gloss of varying intensity.
  2. The material is always matte, for other samples the color and transparency are indistinguishable.
  3. The surface is oily and smooth to the touch. Other varieties, such as PP sheets, appear dry.
  4. Polyethylene products float in water. Most of the alternative models are sinking except for polypropylene.

Rules for joining polyethylene film panels

Welding of polyethylene film

After laying on the floor, the pieces are joined to form a single piece. There are several ways to seal joints.

The welding of the film is carried out by tightly pressing the heated edges of the panels. To carry out the work, you will need special equipment, which is selected depending on the type of product and its thickness. Methods for welding pieces of material:

  1. Resistance welding is considered the simplest and most reliable. It is carried out using a special device consisting of a motor and a gearbox, which drives 2 wheels. A hot wedge is installed between the sheets to be welded, the temperature of which is automatically maintained. It heats the film on both sides and creates a high-strength seam.
  2. Extrusion welding of polyethylene occurs after the molten polymer is supplied under pressure to the joints of the sheets. After softening, they are pressed tightly. The bond strength reaches 70%.
  3. Hot welding is the process of joining the edges of the panels under the influence of hot air and pressing.

The connection with adhesive tape is carried out using adhesive tape for gluing the edges of the film, which has the following properties:

  • The product is intended for sealing joints. It must be reinforced, metallized with a thick adhesive layer - not less than 20 microns.
  • Has a high degree of adhesion.
  • Does not allow water to pass through, well resists aggressive cement mortar.
  • High strength and wear resistant.
  • Provides performance at temperatures from -20 to +120 degrees.

Installation instructions for polyethylene film

How to attach plastic wrap to the foundation

If the building is small, polyethylene can be used as the primary means for horizontal waterproofing of the base.

The creation of a protective "pie" goes like this:

  1. Pour a layer of sand about 0.5 m thick (for soils that can swell in frost) and 0.1 m (for hard soils) into the pit under the strip or slab foundation. The sand cushion will evenly distribute pressure on the soil from the walls, drain water from the structure and protect the thin canvas from damage.
  2. Perform lumber formwork. Mount the connecting elements from the outside so as not to damage the insulator.
  3. Lay the sheets on the sand with an overlap on the formwork and on adjacent pieces of at least 15 cm. Seal the joints with tape or another method.
  4. Gather the reinforcement belt from above and pour concrete into which add a penetrating waterproofing agent.
  5. If the layer is thick, carry out the leveling carefully, taking care not to damage the film. It is not recommended to use metal objects.
  6. Backfill with soft soil to avoid puncturing the insulator.
  7. Another option is that the material is not laid on sand, but on a concrete rough screed. From above, the canvas is poured with a finishing layer.

By laying the film under the concrete screed, the slab foundation is being finalized, which simultaneously serves as a support for the walls of the building and the floor of the lower floor. In this case, the ceilings from below are also protected from leaks. The process takes place in the following sequence:

  • Pour concrete over the base and wait for it to dry completely. The admissible moisture content of the base is 4%. The value can be determined with a moisture meter or indirectly with improvised means. Cut a 1x1 m piece from the foil and glue it to the floor with adhesive tape. If a wet spot appears under the membrane after a day, leave the concrete to dry further.
  • Use a grinder to remove sharp corners and protrusions from the surface.
  • Rub the sinks with cement-sand mortar.
  • Cover the concrete with a nonwoven geotextile, which will create a soft backing that protects the membrane underneath. Lay polyethylene with an overlap on top of adjacent panels.
  • If work is being carried out in a separate room, lay the canvas with an overlap of 15 cm on the partitions, but be sure to fix the compensating elements between the wall and the membrane.
  • Fold the corners and fix with a stapler.
  • Seal the joints with metallized tape or weld.
  • Fill the floor with concrete, on which the walls are being erected.

To waterproof the foundation from the load-bearing walls, clean the upper horizontal surface of the foundation from dust and dirt. Remove items that could damage the material. Level the wall with a cement screed if necessary. Place the overlap film on top of the adjacent sheets. Seal the joints with adhesive tape. On the sides of the partition, the canvas should hang 5 cm.Fill it with a cement solution from above. After the mortar has dried, glue the insulator to the bottom of the partition.

Waterproofing of vertical foundation walls is used for strip structures.After preparing the trench and constructing the formwork, cover the internal vertical and horizontal surfaces with foil. Place the products with an overlap of 20 cm on adjacent sheets, seal the joints with reinforced tape. The polyethylene must extend beyond the edges of the formwork. Carefully install the reinforcement cage inside and fill the trench with concrete. The membrane contributes to its simultaneous solidification throughout its entire thickness, prevents capillary waterlogging of the base during its operation, protects temporary building structures from adhesion of concrete.

Watch the video on waterproofing the foundation with plastic wrap:

The use of polyethylene for waterproofing saves money, but due to its relatively low strength, it must be worked with very carefully. Only a serious attitude to the process will allow protecting the wall from water for a long time.

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