Protection of the foundation from moisture with a PVC membrane, the features of such insulation, its advantages, the preparatory stage of work and the technology of installation of the coating. Waterproofing a foundation with a PVC membrane is an effective way to protect the supporting structure of a house from soil moisture. With its help, it is possible not only to exclude the penetration of capillary water to the surface of the foundation, but also to provide ventilation to its outer walls. In this article, we will consider the features and rules for the device of such waterproofing.
Features of insulation of foundations with a polymer membrane
These membranes are manufactured using advanced techniques. The raw materials for the films are polyvinyl chloride, plasticizers, soot and stabilizers, which provide the protective membrane with resistance to microorganisms, weak solutions of salts, alkalis and acids in the soil.
PVC membranes are very easy to install and strong enough. Their service life can be 50 years or more. The properties of the material are such that they allow the finished coating to ideally fulfill the function of protecting any buried structures. Many PVC membranes are equipped with a signal layer that is bright yellow. By changing it, you can quickly find the waterproofing section damaged during the installation process and take timely repair measures.
PVC membranes vary in thickness, which can be 0.4-2 mm. At a foundation laying depth of up to 10 m, waterproofing membranes with a thickness of up to 1.5 mm are used. If the base of the foundation is located deeper, coverings with a thickness of 2 mm are applied.
Manufacturers produce flat PVC membranes and profiled ones. Flat membranes are used for waterproofing and moisture protection. Depending on this, the thickness of the coating and the method of joining its canvases are selected. Some types of flat films have a corrugated outer surface for better adhesion of the insulation to the mortar.
Profiled membranes are sheets that have spike-like protrusions on their surface. When installing the insulation, these protrusions create a gap between the foundation surface and the membrane. If water gets under the insulation, due to this gap, it is diverted to the drain.
Depending on the soil conditions, multilayer or single-layer profiled insulation is used. In terms of functionality, they are divided into drainage and protective membranes. For example, if drainage is laid along the walls of the foundation, a membrane suitable for these conditions is laid together with a geotextile, which is essentially a filter: it prevents soil particles from entering it, thereby preventing the drainage from silting up. The holes in the geotextile fabric are about 120 microns in size.
The thickness of profiled membranes is usually 0.5-1 mm, and the height of their protrusions is 8 mm. The width of the canvases of such insulation is from 1-2, 5 m. They are attached directly to the surface of the foundation walls.
The fundamental difference between waterproofing a foundation with a PVC membrane from fusing rolled polymer-bitumen products onto it is the absence of the need for continuous gluing of the material to the base.
Another feature of PVC insulation is the possibility of constructing a system suitable for repair in the case of laying a PVC membrane between layers of concrete. The essence of such a system is to divide the insulating layer into special cards and install injection fittings. At the same time, it is possible to quickly determine the location of the leak and eliminate the defect in a separate card, and not in the entire protective circuit of the foundation. Repairs are carried out by injecting polyurethane, epoxy or similar compounds through injection fittings.
Advantages and disadvantages of PVC membrane insulation
In the manufacture of PVC membranes, extrusion and hot air welding are used. With the help of this technology, a high tensile strength of the material is achieved. In addition, PVC insulation has other equally important advantages.
The benefits include:
- Unique durability of the coating without loss of its waterproofing properties. It can last over 50 years, unlike traditional bitumen-based materials.
- Spiked protrusions on the film increase its resistance to bursting.
- PVC membrane is not susceptible to infection by microorganisms, rotting and corrosion, resistant to damage by the roots of shrubs or trees.
- The material is resistant to sunlight, which makes it easier to store it.
- The working temperature range of the finished PVC coating is from -40 to +50 degrees.
- PVC membrane is a chemically resistant material against solutions of salts, acids and alkalis present in soils.
- Due to the special locks located on the membrane sheet, its installation is a simple task. Using mechanical fastening, the insulation can be installed on both vertical and horizontal foundation surfaces.
- Installation of a PVC membrane does not require meticulous preparation of the base.
- The hydrophobicity of the finished PVC coating is practically zero.
The disadvantages include the relatively high cost of the membrane compared to roofing felt or plastic wrap.
Preparatory work before insulation of the foundation
It is more convenient to carry out insulation work on the foundation immediately after its construction. In this case, there is no need to carry out many additional procedures typical for the protection of old underground structures: digging trenches around the perimeter of the house, cleaning buried walls from soil residues, etc.
For comfortable work on waterproofing the foundation with a profiled membrane, the width of the trench along its walls should be 0.8-1 m.
Before installing the membrane, the surface of the bearing part of the building must be primed with a primer. Before applying the composition, the old foundation should be cleaned of dirt, old insulation, traces of fungus, and then the cracks found on the concrete should be repaired with cement mortar. If the foundation has sharp protrusions, they must be removed so that after installation of the membrane, it is not damaged when backfilling the sinuses of the foundation with soil.
Before working with waterproofing, it is necessary to determine in advance the number of rolls of the membrane, the direction of laying its canvases and the areas of joining. You should also take measures to prevent contact of the waterproofing membrane with bitumen, fat, polymers, which can negatively affect its protective properties. For this purpose, it is possible to envisage the use of backing layers, for example from geotextiles.
For waterproofing the foundation, in our case, you will need: a polyvinyl chloride membrane, a profile element for its fasteners, dowels, special high-density polyethylene fasteners and a sealing tape or adhesive. After preparing these materials, you can start the main part of the work.
Foundation waterproofing technology with PVC membrane
We will analyze the process of its installation using the example of the LOGICROOF T-SL polyvinyl chloride membrane, which is produced by the TECHNONICOL enterprise.
Horizontal foundation insulation
On the prepared horizontal base, you first need to lay a lining geotextile, which will protect the waterproofing from damage and reduce the compressive load on it. Its canvases should be laid with an overlap of at least 150 mm and welded together using an industrial hair dryer.
The LOGICROOF T-SL membrane is installed over geotextiles in the same way, except that in this case, welding should be performed, receiving double seams and air cavities at the joints of the sheets, which will make it possible to control the tightness of the welding. Any of these joints should be at least 15 mm wide and the air duct no more than 20 mm wide.
In places of transition of the horizontal surface of the foundation into the vertical plane, it is necessary to install additional strips to strengthen the coating. Their width is assumed to be 1 m. Depending on the load on the foundation, such joints are performed with a fillet (rounding) or without it.
Foundation vertical waterproofing
On the vertical parts of the foundation, the membrane should be fixed by spot welding using air heated by a hair dryer to plastic rondels (circles), mechanically fixed through a lining material to the base. Rondels need to be mounted with a step of 1-1.5 m in the horizontal direction and 2-2.5 m in the vertical direction, while leaving a little more than 20 cm allowances for connection with the next insulation sheet. It is advisable to place a row of rondels vertically near the center of the sheet.
After laying the LOGICROOF T-SL TechnoNIKOL membrane for waterproofing the foundation, a protective layer of thermally bonded geotextile with a bulk density of at least 500 g / m should be made on top of it.2… The overlapping joints of its panels must be welded with hot air. On the walls of the foundation, the geotextile should be fixed pointwise, gluing it to the membrane with polyurethane glue.
On top of the geotextile, a polyethylene film of 200-300 microns should be laid. Its canvases are also connected with an overlap of at least 100 mm, the joints must be glued with double-sided tape. The film prevents the penetration of products resulting from cement hydration into the geotextile. The film is attached to the vertical planes of the foundation with double-sided tape.
Features of welding seams of a PVC coating
Before welding, the joints of the PVC membrane sheets must be cleaned of contamination with a special TECHNONICOL agent. The same cleaner is recommended to be used to remove oil stains that may appear on the insulation during assembly or maintenance of welding equipment.
Welding parameters depend on the environmental conditions in the area of work. They should be selected individually at the beginning of the work shift, after prolonged production breaks or with a pronounced change in the characteristics of the environment in which the membrane is to be installed for waterproofing the foundation. The permissible ambient temperature when welding with a hot air stream should be from -15 to +50 degrees.
In the process of welding, it is recommended to control the quality of the welds obtained. This should be done no earlier than half an hour after their manufacture.
Watch a video about waterproofing a foundation with a PVC membrane:
The use of polymer membranes significantly increases the service life of foundations, since such insulation has a special leak suppression system that meets high requirements and accepted standards.
