Here we will show you a poorly constructed second-floor terrace in a duplex, which was leaking from all sides. I will also demonstrate its remediation.
The terrace in question has a southeast exposure. The covering is granite tiles.
The photos show how the scratched plaster has bloated due to capillary moisture.
In the room adjacent to the terrace, on both sides of the door, the west-facing walls were wet with peeling plaster.
The north-facing wall (relative to the terrace) in the adjacent room was also wet, with damaged plaster.
Below the terrace, the ceiling and the south-facing wall are also wet.
The moisture also affects the electrical distribution boxes, posing a serious risk of fire.
The first step is to remove everything.
The tiles separated very easily from the adhesive, and the adhesive just as easily from the screed.
After clearing the debris, it is evident how wet the screed beneath the tiles is.
The plaster on the balustrade walls was also damaged and had to be removed.
The plaster inside was also in a deplorable condition and had to be removed.
The insulation (TI) of the cooperative is extruded polystyrene (XPS), which had to be cut down to the plinth level for connecting the waterproofing (HI) to the walls.
The bricks on the exterior were also saturated with moisture, and due to the vapor-proof properties of XPS, there was no chance for this moisture to escape soon.
After the walls of the railing dry and are dust-free, they are primed.
The primer I chose is Ceresit CT17.
Technical Specification Ceresit CT17.
After the curing time required for the primer to dry, the walls were plastered with Ceresit CT85 Thermal Insulation Adhesive and Mortar and Ceresit CT325 Fibreglass Mesh 160g/m². A total of 3 coats.
Technical Specification THERMAL INSULATION MORTAR Ceresit CT85
Technical Specification Ceresit CT325 Fibreglass Mesh
The bricks at the plinth level were also primed and plastered:
After the plaster dried, it was time to prepare the base for the waterproofing.
The waterproofing materials I chose are from the German company KOSTER.
KÖSTER Polysil TG500 - Deep penetrating primer for damp and salt-contaminated surfaces.
Technical Specification KÖSTER Polysil TG500.
KÖSTER NB Elastic Grey - Two-component elastic coating, for damp substrates, resistant to pressurized water, pedestrian traffic and UV rays.
Technical Specification KÖSTER NB Elastic Grey
KÖSTER Elastic Fabric - Highly elastic, tear-resistant, finely woven synthetic fabric for reinforcing thin-layer waterproofing.
Technical Specification KÖSTER Elastic Fabric
KÖSTER BD Elastic Tape K 120 - Thin elastic sealing tape for joints and corners, used to connect waterproofing in different surface areas that are prone to cracking in combination with waterproofing systems under ceramic tiles.
Technical Specification KÖSTER BD Elastic Tape K 120
After the primer's curing time, the Elastic Tape K 120 is cut to size.
Next, the Elastic Tape K 120 and Elastic Fabric are embedded in the first layer of waterproofing.
Here is the finished waterproofing.
We continue with patching the thermal insulation using the frame and spot method with the mentioned materials.
Plastering with mesh on the walls up to the window level using the materials described above:
After they dry, waterproofing will be applied over the thermal insulation, and the already laid waterproofing will be connected to the one over the thermal insulation.
The waterproofing has dried, and it's time for the cladding. It's made of textured granite tiles. I didn't like the old tile arrangement design, so I opted for a new look.
The adhesive used for the granite tiles is Ceresit CM17 Super Flexible - Super flexible adhesive for ceramic tiles and granite tiles indoors and outdoors, class S1 according to EN 12002.
Technical Specification Ceresit CM17 Super Flexible
After the floor, it's time for the plinth:
The next step is grouting.
The grout is ARDEX G8S FLEX - Elastic grout, specifically for granite tiles.
Technical Specification ARDEX G8S FLEX
The tiles are grouted, and we continue with decorative acrylic-based facade plaster with added mineral fillers, pigment pastes, and structure-defining round marble grains.
The plaster is polymer-based - Terazid Smartline. The grain size is 2mm. Since it's very difficult to match the exact color of the existing plaster, we chose white, which can later be painted to match the other plaster.
Technical Specification Terazid Smartline.
And here is the final look of the new terrace.
