TECHNICAL SOLUTIONS > WATERPROOFING > Waterproofing of terraces > Waterproofing of inverted roofs

Waterproofing of inverted roofs


When the application of the inverted insulation profile is chosen for the roof, the waterproofing layer of the terrace lies below the thermal insulation, the waterproofing's resistance to the remaining moisture that gets trapped under the thermal insulation, becomes especially important. In addition, the waterproofing material should demonstrate efficient bonding to the substrate, elasticity, reliability and longevity.



The application of AQUAMAT-FLEX, flexible, brushable sealing slurry, covers all the above requirements. Its application to the terrace creates a continuous waterproof coating, with excellent bonding, durability and longevity.



Substrate preparation

  1. Surfaces should be thoroughly cleaned from any loose particles, grease, dust etc.

  2. Any necessary repairs or alterations to gradient are carried out using a strong cement mortar (cement:sand = 1:2 to 1:3), reinforced by adding ADIPLAST polymer latex.
    It is recommended that the bonding of the cement mortar to the substrate is reinforced by applying a bonding layer to which ADIPLAST is also added (cement : sand : ADIPLAST : water = 1 : 1 : 0,5 : 0,5 by volume parts).

  3. The intersection of the terrace with the vertical structures (parapet, stairwell termination etc.), should be dampened and sealed along their entire length using DUROCRET polymer-modified cement mortar, or a cement mortar reinforced with ADIPLAST polymer latex (formation of a 5-6 cm triangular sided groove).Where fast work is necessary, RAPICRET fast-setting patching mortar may be used instead.
    DUROCRET consumption: 1,9-2,7 kg/m length of groove.

  4. The surface is thoroughly dampened, without leaving any water puddles.


Application of AQUAMAT-FLEX

  1. The content of the 25 kg bag (component A) of AQUAMAT-FLEX is added into the 8 kg of liquid (component B) under continuous stirring, until a uniform viscous mixture is formed, suitable for brush application. A low-revolution (300 rpm) mixer may be used for mixing.

  2. A layer of AQUAMAT-FLEX is applied, as wide as the reinforcement (polyester cloth or fibreglass mesh) and while this is still fresh, the reinforcing material is positioned. The procedure is repeated over the remaining surface. The sheets of reinforcing material should be positioned in sequence so that they overlap each other by 5-10 cm.
    After the drying of the layer, 2 more layers of AQUAMAT-FLEX are applied over the entire roof surface. The first layer is let to dry before applying the second. The thickness of each layer should not exceed 1 mm, to avoid possible cracking.
    The waterproofing should be extended at least 15-20 cm up to any vertical surfaces (parapet, stairwell termination etc.), in order to form a watertight basin.
    AQUAMAT-FLEX consumption: 3,5 kg/m2.


Placement of the thermo-insulation boards
On top of the waterproofing layer and after it has dried out, the extruded polystyrene boards are placed, fixed by their weight. Following this, the boards are covered with geotextile or plastic linoleum. Finally, paving slabs or gravel (6-8 cm thick layer) are placed in order to protect the waterproofing and insulation layers from the sun and the wind. This way we also ensure walkability of the terrace.



  • Alternatively for this application, AQUAMAT-ELASTIC can be used instead of AQUAMAT-FLEX.

  • Temperature during application should be at least +50C.

  • The freshly rendered surface must be protected from high temperatures, rain and frost.

  • The material contains cement, which reacts as alkaline with water, so it is classified as irritant.

  • Consult the instructions for safe use and precautions written on the packaging.