A terrace is a structural element that is remarkably different from a balcony, mainly due to the fact that it is located above a particular space (garage, living room, etc.). Therefore, terrace waterproofing plays a key role when it comes to ensuring its sturdiness and longevity. Originally, such spaces were implemented in objects built within the scope of the south hemisphere, where the annual rainfall is much lower than in our climate. Temperatures throughout winter are also much higher there. In our, much harsher climate, structural and finishing elements are constantly exposed to various external factors.

Due to the specificity of our latitude, the element that determines the durability of the terrace is the insulation. In some cases, home owners may want to save some money by limiting the scope of residential building finishing. As a result, an improper type of insulation can be done in said objects. It may then result in an increasing number of leaks and costly repair-related works in the future.


What causes terrace-specific leaks?

One of key atmospheric factors affecting the durability of a given terrace is the so-called temperature amplitude. It can reach up to 50°C (+25°C inside the building and -25°C outside of it). Such difference can translate into the occurrence of remarkable thermal stresses between the individual layers of the terrace. As the laws of physics state, heat always rises up. Therefore, regardless of whether the home owner has opted for the insulation of the terrace made under the tiles or any other type, if it has been executed poorly, the warm air will cause tension. It will lead to scratches and cracking. In a long term, such terrace condition deterioration may cause leaks inside the building and finally – lead to the significant damaging of the terrace. That is why terrace waterproofing can improve its durability.


How to execute a terrace waterproofing-based project?

Terrace waterproofing should start from securing the concrete slab itself. To ensure that the results of such an undertaking are satisfactory, a high-quality roofing felt should be used, for example – WB Hot Mate. It is a roofing felt, but its parameters make it truly stand out from the crowd of other products of such kind. Its thickness is over 5mm and it retains its flexibility at low temperatures, even at -36 °C.

One layer of felt should be put on the board. It will serve as the first waterproofing layer protecting the interior of the building from dampness caused by temperature differences. It should be remembered that warm air rises up. When it gets outside, condensation is formed. In order to drain it onto the roofing felt, a drainage finish should be installed. The drainage mat will easily deal with moisture draining, while WB Hot Mate will prevent it from moving back to the ceiling.

Afterwards, it is required to take care of the insulation of the terrace. To do so, the most effective solution should be taken advantage of, in the form of an XPS material.

The next step should be pouring the floor with a slope on the insulation layer. If there is the need to ensure quick drying of the layer (1 day), one can opt for the WB Fast Floor. WB Fast Floor cement mortar (C-25 class) is a ready-to-use floor screed with accelerated setting time and watertight properties. The prepared screed should then be poured onto the desired surface. The thickness of the layer should be measured with leveled guides made out of metal pipes or rods, on which the mortar should be spread by means of a wooden or metal lath. The floor can be walked on after the elapse of about 30 hours, depending on the ambient temperature and humidity. After pouring the floor, waterproofing can be laid on it even after 3 days.

Preparing the insulation layer of the terrace should be started by priming the surface. The insulation of external terraces requires special attention and care, predominantly due to their location.

Priming the surface will translate into its better adherence to the waterproofing coating. When it comes to the products offered by Water Block, the WB Primer should serve as a primer optimally. Thanks to the fact that it deeply penetrates the material, as well as forms a slightly sticky coating after drying, the waterproofing material in question will perfectly bond with the surface.

After priming the surface, one should apply a waterproofing tape – WB Tape Pro is one of the most important materials when it comes to the entirety of the insulation system. Corners and expansion joints are particularly vulnerable to initial leaks, which results from excessive tension. Therefore, as one of the few manufacturers in the industry, we offer our customers a tape, the parameters of which meet the newest DIN standards. WB Tape Pro is not only a reinforcing product, but also a sealing one. Its width, equal to 12 cm, ensures the accurate protection of internal and external edges. Making a terrace waterproofing system this way ensures its perfect tightness.

If the surface has been primed and the WB TAPE PRO tape has been applied, one can proceed to laying the final layer of terrace waterproofing. In order to do so one needs two different waterproofing solutions: WB DUO FLEX as an adhesive for WB MEMBRANE and a waterproofing layer, as well as WB 2K as the final layer, which is applied after covering the surface with the WB MEMBRANE material . Both insulations are characterized by the ease of application and a remarkable adhesion to the surface. They create flexible coatings that are resistant to freezing and thawing cycles. They remain flexible even at very low temperatures. WB MEMBRANE strengthens the surface and improves its tightness in spots characterized by a very high water pressure. It has the hydrostatic pressure load capacity of 0.5 MPa, temperature resistance from -30 °C to + 90 °C, as well as high tensile strength up to 13 MPa . It is capable of withstanding water pressure of 50 meters per 1 square cm. The utilization of WB MEMBRANE in terrace and balcony systems guarantees tightness for many years, even in extreme weather conditions. The insulation being a part of the system can be covered with traditional finishing cladding, such as adhesive tiles, as well as with ventilated systems, including slabs on brackets and terrace boards.



Sequence of terrace insulation-related works:

Materials required for terrace insulation:

Required finishing materials:

  • Concrete slabs – granite

  • Terrace brackets

  • Aggregate or grass


  • Balcony tiles – not larger than 60cmx60cm – recommended tiles: 30cm x 30cm attached with WB FLEX GLUE with a wide joint of minimum 6mm filled with WB Fuga Flex.



If you are not sure how much material you may need to insulate your terrace, you can always ask our professional support. Just contact our technical team via phone or e-mail.



As a finish, it is possible to use ventilated solutions, such as boards on adjustable brackets or a composite board.

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How to install the membrane wb:

WB Membranes instructional video:

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Water Block are premium class products designed for customers who value solutions for years. Long-term cooperation of technologists from Poland and Switzerland has allowed us to create complete system solutions for such structural elements of the building as balconies, terraces, roofs and foundations. Water Block is successfully used wherever parameters such as high flexibility, resistance to low temperatures or resistance to water pressure are important.

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