Installation of pvc membranes for roofing: technology of
There are many traditional roofing materials, many of which are very popular and widely used even now. Using the latest technology helps to make the roof more reliable and durable, one of them is a membrane one. The use of this method allows you to create an almost monolithic protective layer with excellent waterproofing characteristics. There are several ways to fix the coating, therefore, mentioning each of them, we will describe how the installation of PVC membrane for the roof. Having completed the work once, you no longer have to think about repairing the roof every year.
Materials used
There are several types of membranes used for waterproofing the surface of roofs. Each of them is fundamentally different from traditional materials and has its own pros and cons. The following types of films can be distinguished:
- PVC;
- EPDM (base ethylene-propylene rubbers (synthetic rubber));
- TPO (based on thermoplastic olefins).
Consider each material in more detail.
In the manufacture of PVC membranes, in order to make the coating more elastic, special volatile plasticizers are added to polyvinyl chloride, which ensures the formation of a durable and reliable protective layer. The assembly is carried out using welding so that the joining zones of individual surface segments (webs) are not inferior in their strength to “solid” sections. The disadvantages of polyvinyl chloride include the presence of volatile substances in its composition, as well as susceptibility to the effects of solvents, various oils and bitumen.
The EPDM membranes are strengthened (reinforced) by adding polyester plasticizers in them in the form of thin filaments. Featuring high plasticity and long service life, this material is relatively inexpensive. Their only drawback is the need to use a special adhesive composition that securely connects the individual sheets. A problem place is considered to be joints, which forces a potential executor to pay special attention to them.
A thermoplastic olefin-based waterproofing film can also be reinforced with fiberglass or polyester. The option of execution which does not assume strengthening of the covering layer with special plasticizers is possible. When mounting sheets of TPO membranes, hot air welding is used to connect them together, which ensures very strong joints. A significant disadvantage of materials of this class is their low elasticity.
The known technologies for arranging the listed coatings can differ significantly from one another. Practice has shown that the following techniques are the most commonly used:
- ballast fixation;
- mechanical fastening;
- simple sticking;
- use of heat welding technique.
In the following sections, each of these techniques will be discussed in more detail.
Ballast mount
The easiest way to install (including the roofing of PVC) is their ballast binding. The procedure for implementing this method is as follows:
- Roof strips laid on the roof are neatly leveled and fixed around the perimeter with glue;
- a ballast is poured over the decomposed film, in which the fractional river pebbles, crushed stone or rounded gravel are commonly used;
- when using crushed stone or gravel with sharp edges in order to avoid damage to the film, a protective covering of non-woven cloth is first laid over it.
Mechanical mount
If the supporting structure of the roof is not designed for large loads, allowing the implementation of the ballast fixation option, it is necessary to apply their so-called mechanical fixing. This method of installation is also resorted to in cases where, due to the particular configuration of the roof, it is not possible to use other methods of fixing waterproofing.
The mechanical method can be used for arranging reinforced concrete and corrugated roofing, as well as for waterproofing wooden foundations. According to this method, the laying of the membrane coating is carried out with the help of special "edge" rails with a special sealing layer. At the same time, as a direct fastener, special telescopic nails with a wide plastic cap are used. Anchoring points are selected on the overlap areas of individual canvases of roofing membranes with mounting pitch of the order of 200 mm. At angles of inclination of blood exceeding 2? 4? C, additional fasteners are provided in the area of the valley.
The situation with laying the protective layer on the concrete base of the roof deserves special discussion. They are first laid down, the so-called geotextile layer, on top of which the roofing film is mounted.
Sticking
The technique of gluing PVC membranes is considered to be a rather costly measure, which does not provide the required reliability of the seam. For this reason, it is used very rarely and is usually used only in cases where other methods are not applicable. In its implementation, it is necessary to choose such adhesives, the tensile strength of the adhesive joint in which is significantly higher than that of the material being glued.
When using this fixation technique, the gluing of individual strips of the web is made not over the entire area, but only along its edges. In addition, the gluing points can be selected in the overlap zones of adjacent panels, as well as in the places where the film fits on the vertical planes (on the edges, in the valley, etc.).
Heat welding
Note! Welding of PVC films by welding will require special equipment that generates a hot stream of air with a temperature along the axis of the order of 500? 600? C. The width of the resulting weld should be in the range from 20 to 100 mm.
This method of joining individual panels of roofing material provides a high level of tightness of the layer. The resulting seam (as opposed to the adhesive method) is insensitive to ultraviolet radiation.
Today, heat welding is the most reliable and promising bond of waterproofing.
The technology of mounting membrane coatings described in this article can be used both in the construction of large industrial facilities and in private construction.