By admin 
Waterproofing of occupied roofs is a crucial element that ensures reliable protection of the building from moisture penetration, as well as the durability and safety of the roofing system itself. An occupied roof implies the use of the roof surface not only as a protective layer but also as a functional area — terraces, gardens, recreational spaces, or technical platforms. This imposes special requirements on waterproofing materials and installation technologies.
Unlike traditional roofs, occupied roofs are subjected to additional mechanical loads, standing water, and temperature fluctuations. Therefore, waterproofing must be extremely durable, elastic, resistant to damage, and have a long service life. Proper waterproofing prevents structural damage, mold growth, and leakage risks that may lead to costly repairs.
This article explores the features of waterproofing for occupied roofs, types of materials, installation technologies, and recommendations for operation and repair.
Features of Occupied Roofs and Waterproofing Requirements
An occupied roof is designed for regular use as a functional surface. It may include open terraces, green roofs, sports fields, recreation areas, and technical platforms with equipment. Such roofs experience significant mechanical loads, UV exposure, moisture, and temperature changes.
The main task of waterproofing in these systems is to ensure complete tightness and protection against water penetration, including standing water that can accumulate on the surface. Additionally, waterproofing must have high tear strength and resistance to mechanical damage, as the roof is subject to loads from people, furniture, plants, and equipment.
Durability and resistance to UV and aggressive environments are key requirements, since waterproofing is often on or near the surface. Compatibility with other roofing layers, such as insulation, drainage, and covering, is also important.
Types of Waterproofing Materials for Occupied Roofs
The modern market offers a wide range of waterproofing materials, which can be roughly divided into several groups: roll materials, liquid membranes, polymer films, and mastics, as well as composite systems.
Roll materials are bituminous or polymer membranes laid on a prepared base using hot air, adhesive, or mechanical fastening. They have high strength, elasticity, and waterproofness. Modified bituminous membranes (PVC, TPO, EPDM) are often used, distinguished by UV and mechanical resistance.
Liquid membranes are polymer compositions applied with brushes, rollers, or spraying, forming a seamless waterproof layer. They are ideal for complex architectural shapes and hard-to-reach areas. Liquid membranes have high adhesion and elasticity but require careful surface preparation.
Polymer films are thin but strong materials laid on the surface serving as a moisture barrier. They are often combined with other waterproofing layers for enhanced reliability.
Mastics are bitumen-polymer or polymer compositions used for local repairs or additional sealing of joints and flashings. Mastics have good adhesion and weather resistance.
Material choice depends on the roof type, operating conditions, budget, and durability requirements.
Installation Technology of Roll Waterproofing on Occupied Roofs
Installation of roll waterproofing materials requires thorough base preparation. The base must be strong, flat, clean from dust, dirt, and old coatings. The surface should be dry and free of defects that could damage the membrane.
Roll installation usually starts from the lower edge of the roof, with overlaps between sheets depending on the material type and manufacturer recommendations. Overlaps are glued or hot-air welded to ensure full seam tightness.
Mechanical fasteners are used in areas with high wind loads or on vertical surfaces. Avoiding folds and bubbles is critical as they may cause leaks.
After installation, quality control includes checking welded seams and coverage integrity. For occupied roofs, an additional protective layer such as paving slabs or turf is often installed to distribute loads and protect the membrane from damage.
Features of Using Liquid Waterproofing Membranes
Liquid membranes are modern polymer compositions that form a seamless elastic layer upon application. They are especially demanded on roofs with complex shapes, numerous flashings, projections, and other architectural details.
Before applying liquid waterproofing, the base must be thoroughly prepared — cleaned, leveled, and possibly primed to improve adhesion. Coatings can be applied in multiple layers to achieve the required thickness and reliability.
Liquid membranes have high resistance to UV, weather, and temperature fluctuations. Their elasticity allows them to compensate for substrate deformations without damage.
However, liquid membranes require adherence to application technology, including temperature regimes and drying times between layers. To protect against mechanical damage on occupied roofs, protective coverings such as slabs, paving tiles, or special coatings are installed over the membrane.
Role of Drainage Layer in Occupied Roof Waterproofing System
The drainage layer is an important element in the occupied roof structure, especially for green roofs or those with vegetation layers. It provides excess moisture removal, preventing water stagnation and reducing load on the waterproofing layer.
Drainage can be made from special geomaterials, perforated slabs, or gravel bedding. The choice depends on roof type and operating conditions.
Proper drainage organization increases waterproofing lifespan by preventing saturation and mechanical destruction. It also reduces the risk of mold and fungi in insulation and roof structures.
Drainage systems must ensure free water exit through drains and rainwater systems to avoid overflow and roof damage.
Interaction of Waterproofing with Other Roofing Layers
Waterproofing of an occupied roof does not work in isolation but is part of a complex multilayer system. It interacts with insulation, vapor barrier, drainage, and protective coverings.
The waterproofing layer must be compatible with insulation, preventing its wetting, which may reduce thermal performance and damage the structure. Thus, waterproofing must have sufficient mechanical strength and chemical resistance.
The vapor barrier, placed below insulation, prevents water vapor from interior air entering insulation, reducing condensation risk. A ventilation gap or drainage layer is created between vapor barrier and waterproofing for moisture removal.
Protective coverings such as paving slabs, turf, or special plates distribute loads and protect waterproofing from mechanical damage, UV, and temperature effects.
Technical and Operational Features of Occupied Roof Waterproofing
Occupied roofs impose increased technical requirements on waterproofing. Materials must have high tensile strength, puncture and abrasion resistance, and retain elasticity at low temperatures.
UV resistance is also crucial since waterproofing often lies on the surface or under transparent coverings. Materials must maintain properties throughout service life, which can exceed 25–30 years.
Chemical resistance is important, especially if fertilizers, aggressive detergents, or contact with plants and soil occur on the roof.
Operation requires regular visual inspections, timely repair of damages, and cleaning of surface contaminants to prevent premature waterproofing failure.
Repair and Maintenance of Occupied Roof Waterproofing
Repair of occupied roof waterproofing must be timely upon detection of damages, leaks, or wear signs. Depending on damage type, local or major repair methods are used.
Local repair usually involves mastics, patches from roll materials, or application of liquid waterproofing on damaged areas. Surface must be cleaned and dried before repair.
Major repair may require replacement of the entire waterproofing layer or significant parts due to loss of tightness and protective properties.
Routine maintenance includes cleaning debris, leaves, dirt, and checking protective coverings. Timely maintenance significantly extends waterproofing and roofing system service life.
Comparative Table of Main Waterproofing Materials for Occupied Roofs
| Parameter | Bituminous Roll Membranes | Polymer Membranes (PVC, TPO, EPDM) | Liquid Membranes | Mastics |
|---|---|---|---|---|
| Waterproofness | High | Very High | High | Medium |
| Elasticity | Medium | High | Very High | Medium |
| UV Resistance | Medium | High | High | Medium |
| Tensile Strength | High | Very High | Medium | Low |
| Ease of Installation | Medium | Medium | High | High |
| Repairability | Medium | High | High | High |
| Cost | Medium | High | Medium | Low |
Conclusion
Waterproofing of occupied roofs is a complex and responsible process requiring proper material selection, adherence to installation technologies, and regular maintenance. The quality of the waterproofing layer directly affects the durability, safety, and comfort of the building.
Modern materials and technologies enable the creation of reliable and durable roofing systems capable of withstanding high loads and harsh climatic conditions. Careful waterproofing installation and timely repairs significantly extend the service life of occupied roofs.