Waterproofing of the exploited roof: features and review of the best materials

Making sure your roof is adequately waterproofed is essential to preventing water damage to your house. A well-waterproofed roof prolongs the life of your roof structure while also keeping your living area dry and comfortable. When thinking about waterproofing an existing roof, there are a number of important components and materials to investigate.

When waterproofing an existing roof, material selection is one of the most important factors to take into account. There are several choices available, each with benefits and suitability unique to your roof’s requirements. Bituminous coatings, elastomeric coatings, and liquid applied membranes are examples of common materials. By forming a seamless barrier against moisture, these materials are intended to stop leaks and potential structural damage.

Every kind of waterproofing material has advantages and a special way to be applied. For instance, liquid applied membranes are flexible and simple to apply, which makes them appropriate for roofs with irregular surfaces or complicated shapes. On the other hand, bituminous coatings offer superior resilience and UV radiation resistance, which makes them perfect for roofs exposed to inclement weather.

Think about things like climate, roof slope, and current roof condition when choosing the best waterproofing material for your roof. Speaking with a roofing expert can give you important information about what kind of material will protect and last the longest on your particular type of roof.

Maintaining continuous roof waterproofing efficacy also requires routine maintenance and inspection. Even the best waterproofing materials can deteriorate with time as a result of weather exposure or normal wear and tear. You can save money on repairs and preserve the structural integrity of your home’s roof by taking quick action when you notice any damage or deterioration.

"In terms of roof maintenance, making sure that buildings are waterproofed effectively is essential to preventing water damage. This article explores the fundamentals of waterproofing existing roofs, emphasizing important characteristics and giving a summary of materials that are highly recommended. Both professionals and homeowners can protect their properties from leaks and structural deterioration by investigating these factors and making well-informed decisions."

Features of waterproofing of the operated roof

The load on the waterproofing layer is negligible if the flat roof is nonexplosive; in these cases, the hydraulic barrier also functions as the roofing. As a result, it is simple to locate and fix leaks on an inflammable roof, and overhauls typically only require changing the outdated hydraulic tank or applying a fresh layer.

A far greater load is placed on the operated roof waterproofing. Above the hydraulic battle of such a roof, there is, at minimum, a screed and a finish coating; at maximum, there is a thick layer of soil with plants, up to large trees, growing in it. Remember the point load created by people walking along the roofed terrace, furniture legs resting on it, and flowerpots filled with flowers.

Furthermore, the cost of error increases when the operated roof is waterproofed. Because the roofing pie on such a roof is more intricate than that of an unexplodable roof, repairs will be much more expensive because multiple layers of material must be removed in order to access the leak.

That’s why there are now more demands placed on waterproofing material and installation quality.

Requirements for waterproofing materials

The operational roof’s waterproofing should be:

  1. Wear -resistant – Although the hydraulic boar is in the bowels of the roof cake of the operated roof, it is still subjected to an abrasion load that the neighboring solid layers transmit to it.
  2. Durable – waterproofing on the operated roof should last at least 30 years.
  3. Elastic – with a point load, the hydraulic tank must be stretched, and then quickly return the original form.

For the operated roof, it is preferable that the roll waterproofing be installed by welding the paints together. If you look at the technology, the adhesive method and the melting of waterproofing are also trustworthy mounting techniques. However, it is more challenging to inspect the installation quality in this instance.

While weight, durability against UV rays and chemical exposure, and ease of maintenance are all significant factors for standard flat roofs, they are practically irrelevant for the installation of an operating roof.

Place of waterproofing in the roof cake of the operated roof

There are two types of operated roofs, depending on where the waterproofing layer is located in the roof pie:

  • Traditional,
  • Inversion.

Waterproofing of the conventionally operated roof The process involves laying down a base made of wood, paving slabs, terrace boards, or gravel sprinkled on top of a heating or sloping layer, followed by drainage with a filtration canvas on top.

Installing a traditional flat roof is a little less expensive, and you can use any type of insulation—even non-flammable, low-cost mineral wool—when it comes to insulation. However, this is where its benefits end: the point load on the waterproofing does not soften, and the hydraulic tank ages more quickly as a result of temperature variations, lowering the roof’s overall lifespan.

When the roof waterproofing device is installed beneath the insulation, it is inversion operated. Additionally, drainage and additional layers are already arranged on top of the insulation:

Mineral wool and other fibrous forms of thermal insulation materials cannot be used in this situation because the insulation is not waterproofed against moisture. Even a small percentage increase in humidity causes this type of heater to lose efficiency multiple times over. Alternatively, dense, moisture-resistant materials such as polyurethane slabs, foam, or extruded polystyrene foam are laid. Even in the absence of a waterproofing layer, these kinds of thermal insulation materials essentially never get wet and retain their characteristics.

Although the installation of inversion waterproofing on an operated roof is more costly, the benefits are largely equivalent because the hydraulic barrier within is shielded from temperature fluctuations, point loads, and insulation. In addition, in order to prevent crushing and cracking, the insulation itself must be shielded from point loads. However, failure to do so will only cause damage to thermal insulation, which will increase heat loss through the roof and have no effect on its dependability.

Materials for waterproofing the operated roof

The operating roof is waterproofed using three types of materials:

  • rolled bitumen waterproofing;
  • sprayed and bulk coatings;
  • Polymer membranes.

Bitumen roller materials

It is immediately impossible to use inexpensive roofing material on an operational roof. The bitumen that covers roofing material is prone to cracking when temperatures drop, as well as from occasional light mechanical exposure and even simple wear and tear. Furthermore, such bitumen ages quickly—it takes no more than five years to reach its "old age." As a result of moisture seeping through the cracks, the roofing material literally spreads to pieces and the cardboard base soaks. Roofing waterproofing has a service life of no more than seven years, which is extremely short for an operational roof.

For the same reason, the operated roof cannot be waterproofed by any close relative of the roofing material based on regular or modified bitumen. Roller materials that contain bitumen and polymer The polyester non-woven canvas base and binding are incredibly strong, elastic, and long-lasting, giving the roof at least 25 to 30 years of use without the need for major repairs.

Advantages and disadvantages

For the purpose of waterproofing operated roofs, rolled materials are chosen because:

  • low price;
  • simplicity of installation;
  • elasticity and flexibility;
  • universality;
  • incompetition to the qualifications of installers.

To put it simply, roll waterproofing is inexpensive, highly dependable, and easily findable labor for installation across the nation because most roofers are familiar with it.

However, despite all of its benefits, bitumen-polymer roll waterproofing

  • will last less than other materials;
  • relatively easily damaged;
  • demanding on storage and delivery conditions;
  • during installation gives a lot of joints – potential leaks.

For less expensive construction, rolled waterproofing is a good option; however, if durability and dependability are crucial, it is preferable to use alternative materials.


Bitumen-polymer roll waterproofing is easy to install, but it does require attention to detail and following directions. On a concrete base, roll waterproofing is laid in five steps.

Surface preparation

The concrete base needs to be cleared of debris and pollutants, elements that are easily exfoliated removed, and surface imperfections like chips, cracks, and shells leveled. At all points and in all directions, the base should be level with a deviation of no more than 5 mm per 2 m of the surface.


It is necessary to remove any small dust on the foundation since it deteriorates the roll waterproofing’s adherence. High-pressure washes or industrial vacuum cleaners are used for this. Before commencing work, the concrete must be given time to completely dry.

Applying the primer

In order to improve the roll material’s adherence to the base, a bitumen primer must be applied to the operated roof’s surface prior to waterproofing it.

A special drill nozzle or a thorough manual mixing method are used to combine the bitumen primer. Next, using a brush or roller, a thin layer of it is applied to the base in the form of parallel stripes. Using a brush, separately smear the corners next to walls, parapets, ventilation mines, and other roof adjustments to vertical structures. Additionally, the primer is given time to fully dry.

Checking if the base is ready is as easy as applying your hand to it; the primer shouldn’t be tacky to the touch or leave black marks on your skin.

Laying the first layer of roll waterproofing

Sales installs bitumen-polymer waterproofing on the operational roof. Roll the roll first, level it, and then let it rest. then begin the installation by rolling once more on both sides to the center.

The gas burner heats the concrete base and the lower portion of the waterproofing, gradually rolling the roll onto itself. Since bubbles, bends, and other flaws should not be present in waterproofing, the roll is immediately rolled from the center to the edges using a heavy metal roller after it has melted.

At least 100 mm should overlap on the sides, and at least 150 mm on the end, between the rolls.

Laying the second layer of waterproofing

Roll waterproofing is melted in two, and occasionally three, layers for increased dependability. The joints between the rolls of the second and subsequent layers should be strictly in the center of the previous layer’s stripes when sailing. Everything else is carried out in the same manner as the first layer.

In any case, it is not crucial to avoid stepping on rolls during installation as this can harm the bitumen layer and compromise the waterproofing layer’s tightness. It’s also important to make sure that the adjacent stripes’ end joints are spaced apart by at least 500 mm when laying them.

Bulk and sprayed waterproofing

Joints are any waterproofing system’s primary weak point. Consequently, of all the roller waterproofing types, the material that settles on the base with a monolithic coating is the most dependable. irrespective of the roll’s width.

They include sprayed waterproofing as well as bulk waterproofing. Layer by layer, they are applied to the base until the required thickness of the hydraulic tank is reached. Depending on the task, conditions, and type of material, this thickness can range from 0.5 mm to 15 mm.

Besides dependability, mass, and sprayed waterproofing:

  • hermetically closing the locations;
  • may limit the surface of the base;
  • very elastic;
  • Resistant to the constant exposure of water – many types can be used in the arrangement of pools;
  • Durable.

In terms of the primary three’s shortcomings:

  • CENE is significantly higher, than roller bitumen-polymeric materials.
  • WITHThe falsity of the coating: For the device of sprayed waterproofing, special expensive equipment and high qualifications of workers are needed; When working with bulk waterproofing, it is important to constantly monitor the thickness of the layer.
  • DGreat work – Sometimes the application of such waterproofing takes weeks.

Bitumen mastic

Ordinary bitumen mastic is inappropriate for waterproofing the exploited roof, just like it is not for rolled roofs. Even altered pieces are too brittle and fleeting for this. However, mixed species are employed quite frequently:

  1. Bitumen-polymer mastic -elastic, resistant to mechanical loads and temperature differences, material that serves 25-30 years.
  2. Bitumen-Latex mastic, which is often called liquid rubber due to extreme elasticity and the ability to self-ensure small damage to the coating. Helps to avoid leaks even on hazardous flat roofs, as it withstands pressure up to 1 MPa. Service life – 30+ years, provided that the correct application.

Mastic with a bitumen base is the least expensive waterproofing solution. It is therefore most frequently used.

In order to waterproof the exploited roof using mastic, you must first prepare the surface, then reveal it and apply two layers of bitumen primer to the base. The process for doing all of this is the same as for applying roll bitumen waterproofing. Unless grinding the concrete base is recommended.

The mastic itself is applied once the primer has dried:

  1. If the temperature of the mastic is less than +5 ° C, then before starting work it is brought into a warm room for a day and allowed to warm up.
  2. Then the mastic is mixed. If the composition is two -component, then the second component of mastic is introduced, as a rule, in small portions, and not pour everything at once.
  3. With a brush, roller or special trowel, mastic is applied with a thin layer to the surface, preferably parallel stripes. It is important that there are no unlifted areas, therefore, the mastic is “driven” into the corners with a hard brush.
  4. The layer of mastic is allowed to dry. Depending on the type of mastic, this can take it for less than an hour (latex trains dries especially quickly), and for more than a day. Dried mastic does not stick and do not get his hands.
  5. The second layer of mastic is applied to the first layer in exactly the same way.
  6. The process is repeated until the thickness of the waterproofing is sufficient for the exploited roof. Usually it is 5-6 layers or 4-5 mm or more, but a specific figure depends on the type and manufacturer of mastic.

It is crucial to apply mastic in thin, infiltrating layers, regardless of the kind. If not, it might not dry well.

Polyurethane mastic

This composition is based on polyurethane, which freezes quickly, applies easily, and provides a 40–50 year coating. Since polyurethane comprises up to 80–90% of the solid fraction and only 10–20% of the solvent, it is essentially not seated like bitumen mastic. In contrast, up to 80% of the solvent can be found in the bitumen mastic’s composition. Working with polyurethane mastic is safer from the perspective of worker health and fire safety because of the small amount of solvent.

Mastic may actually contain additional polymers in addition to polyurethane to enhance its specific qualities, such as elasticity, strength against gaps and punctures, drying speed, resistance to wear, and temperature changes resistance.

Polymer mastic is one of the best options for waterproofing the operated roof. It is elastic, long-lasting, applies quickly, provides excellent moisture protection, and "breathes," or allows water vapor to escape rather than condense on the surface.

The two main disadvantages of polymer mastic are its high cost and the requirement for a 0.5–0.6 mm thin layer to be applied. A thicker layer of polyurethane mastic will cause it to "boil," or produce bubbles on the waterproofing surface as a result of the polymerization reaction occurring in the thickness. As a result, the coating’s ability to repel water will be diminished.

Although bitumen mastic and polyurethane application techniques are similar, there are a few key variations:

  1. The surface should be even, even small chips, shells and other defects must be sealed with a repair mixture or a special sealant.
  2. Grinding a concrete base is required.
  3. Before applying mastic, the surface is primed and reinforced in the places of junctions and deformation seams. To do this, apply polyurethane mastic with a strip of 150 mm to problem areas, let it dry a little (no more than 20 minutes) and attach a geotextile with a width of 100 mm on it.
  4. Polyurethane mastic is applied to a well-dried base with rollers or brushes at the rate of 0.5-1.2 kg/m 2, depending on the type. The second layer, it, as a rule, is the latter, is applied only after the first dries – usually it takes from 12 to 48 hours. The third layer is needed only if the total consumption of the material for the first two layers is less than the manufacturer specified.

The characteristics of bitumen vary considerably less than those of polyurethane mastics from different manufacturers. Consequently, always carefully read the manufacturer’s instructions and the information on the label before beginning any work.


A relatively new kind of isocyanate-based waterproofing coating is called polymochevin. A thin layer of the composition is sprayed onto the roof; it dries in less than an hour and can withstand temperatures as high as -60°C to +150°C. Among the waterproofing materials used for operated roofs, this one is the most durable, with a lifespan of at least 50 years. When applied, polymochevina coating is even less sensitive to moisture than polyurethane mastic, making it much more elastic.

Despite having all these qualities, polymochevin is very uncommon due to its high cost. This holds true for both the composition and the specific tools needed to work with it. Additionally, the use of polymochevina requires special training and qualification for workers. Additionally, these are extra expenses.

Apply polymochevin to a surface that has already been prepared; all flaws must be embedded or arranged in the same order as for polymer mastic. This also holds true for junction reinforcement. After that, primer is applied, though you can skip it if the surface has been thoroughly cleaned. Additionally, apply one or more layers of polymer spray to the roof itself if it is inverse. The operating roof’s waterproofing requires that each layer of polymochevina have a minimum thickness of 2.5 mm.

A layer of polyurethane thermal insulation with a density of at least 60 kg/m 3 is frequently sprayed in front of the polymochevina on the roofs of the traditional design. This simultaneously addresses three issues: base preparation costs, surface alignment, and insulation. Unlike polymochevina, polyurethane foam precisely fills in screed imperfections.

Polymer membranes

The second most popular option, after rolled polymer-bitumen materials, is waterproofing the exploited roof with a polymer membrane. Such waterproofing is elastic, resistant to temperature fluctuations, well-opposed to abrasion, and has a service life of at least fifty years. And all of this comes at a very low cost: slightly more than rolled bitumen materials, but far less than bulk or sprayed waterproofing.

Polymer membranes come in three varieties: EPDM, PVC, etc. However, PVC membranes are nearly always utilized for waterproofing operated roofs.

First of all, because the membrane is double-layered, the welded seam created during the installation of the rolls is stronger than the canvas itself. Second, the material is predictable due to its ease of production. Despite all of their great qualities, TPO membranes are highly susceptible to production technology compliance, which can result in variations in material quality. Furthermore, this is not acceptable for waterproofing.

Telescopic fasteners are used to mechanically install PVC membrane waterproofing on the traditional structure’s operational roof. Additionally, since mineral wool and PVC membranes are fully compatible, mineral wool is typically used as a heater. In the event that the thermal insulation layer is comprised of extruded polystyrene foam or polyurethane plates, a geotextile protective layer must be placed between the insulation and the membrane.

The procedure itself appears as follows:

  1. The canvas of the membranes is fixed along the end of the fastener and gently unfold, pulling.
  2. The stretched membrane is attached from the second end and, if this is the first strip, along the long side of the adjoining.
  3. The membrane is pulled again, but already across, and again fixed.
  4. 4. Then a second canvas with a lateral overlap of 120 mm and a end shift is laid at least 300 mm.
  5. Two rolls of PVC membranes are welded so that the second canvas closes the fasteners. Then everything is repeated, but all the rolls, except the first, are fixed with fasteners on only one side.

The PVC membrane on an inversional roof is installed over a concrete base that needs to be prepared similarly to bulk waterproofing. Geotextiles must then be placed on the screed, and only then can the membrane be mounted.

Making sure your roof is adequately waterproofed is essential to preserving the structural integrity and lifespan of your house. The correct materials and methods can make a big difference, whether you’re working on an old roof or designing a new installation.

The state of the existing roofing materials is one of the most important factors to take into account when waterproofing an existing roof. It is imperative to evaluate any wear or damage prior to using fresh waterproofing materials. There may be better materials for a given type of roof—pitch or flat, for example.

Because of their resilience to weathering and longevity, materials such as TPO (thermoplastic polyolefin) membranes and EPDM (ethylene propylene diene terpolymer) rubber are commonly used for flat roofs, which are prone to water pooling. When installed properly, these materials offer a seamless barrier against water infiltration.

Conversely, metal or asphalt roofing—which provides superior waterproofing qualities when installed with the appropriate underlayment and flashing—is frequently advantageous for pitched roofs. These materials improve your home’s overall aesthetic appeal in addition to providing water resistance.

Think about things like longevity, maintenance needs, and climate when choosing the best waterproofing material. Materials with outstanding UV resistance and flexibility, such as silicone or acrylic coatings, are adaptable choices that can be used on a variety of roof types.

In the end, by averting expensive repairs from water damage, investing in premium waterproofing materials and expert installation can save you both money and time. Effective waterproofing should be your top priority when doing repairs on an old roof or making plans for a new one. This will guarantee that your house is secure, dry, and safe for many years to come.

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Alexandra Fedorova

Journalist, author of articles on construction and repair. I will help you understand the complex issues related to the choice and installation of the roof.

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