Waterproofing Terraces and Balconies

Prior to undertaking the waterproofing of balconies and terraces, a thorough check of the substrate should be undertaken to ensure it is suitable and compatible with the proposed waterproofing membrane system. As balconies and terraces are constantly exposed to rain splash water and high-temperature fluctuations, the waterproofing system used should be crack bridging.

Different waterproofing systems can be offered:

• Liquid applied bituminous waterproofing system: apply a bituminous waterproofing primer on a clean, solid, and well-prepared substrate. Install in wall floor joints a protective layer to protect from damage caused by movements. Apply thereafter for waterproofing two layers of a suitable liquid applied bituminous waterproofing embedding a glass fiber mesh into the first waterproofing layer.
• Cold applied self-adhesive system: apply a solvent-free, highly elastic bitumen/rubber-based sealing compound on a clean, solid- and well-prepared substrate to provide good adhesion of the waterproofing system to the substrate. Install a fillet in the wall-to-floor junction. Apply a cold applied self-adhesive rubber/bitumen waterproofing membrane. Ensure bonding of the waterproofing membranes onto the prepared substrate with overlaps of membranes over each other of about 10 cm on each side. Vertically applied membranes can be mechanically fixed. Protect the waterproofing system against mechanical damage with a screed, installing a gliding PE foil layer under it.
• Bituminous membrane system: When applying bituminous membranes care should be taken to ensure the rolls are laid out uniformly. Rolls should be stored standing up as horizontal stacking might damage the material, particularly under sun heat. The substrate must be clean, dry, and free of dust and debris. Subsequent to the application of the adhesive membranes, a tile adhesive can be spread for the application of tiles.
• Polyurethane liquid membrane system: If applying a polyurethane liquid membrane, apply a primer coat and then apply a first coat of the polyurethane liquid membrane. Apply a second coat after 12 to 18 hours but not later than 48 hours. Apply geotextile to protect the waterproofing membrane. Liquid applied membranes must fully cure before being considered fit for waterproofing. Low temperatures, wet film thickness, relative humidity, solids content, and air movement will delay curing. The premature covering may prevent curing and lead to degradation.
• Polyurethane modified methyl methacrylate: The combination of polyurethane and methyl methacrylate assures that the finished system is rapidly ready for use and can also be applied during the winter period at very low temperatures. The different products that make up the system cure to form a highly elastic foot trafficable waterproof system on old or new concrete, tiles, metal, wood, epoxy, and methyl methacrylate existing deck coatings.
• Mineral-based waterproofing system: An alternative to bituminous, polyurethane, or cold-applied membranes is the application of a cement-based mixture to which polymers and other elements impervious to water are added. Before proceeding with the installation of a mineral waterproofing system, apply a solidifying silicate-based product to harden the substrate. Alternatively use an in-depth waterproofing slurry by crystallization to strengthen and waterproof the concrete. Apply thereafter a crack-bridging two-component polymer-modified surface water-proofer with hydrophobic and elastic properties, which is resistant to foot traffic and can be covered with tiles, applying in the wall-floor junction and areas subject to damage from cracking, in the fresh first waterproofing layer, a high strength polyester nonwoven reinforcement fabric. The tiles are applied over this cementitious layer with an appropriate tile adhesive. The cement layer, in practice, is not perfectly waterproof and could dilate or shrink as a result of changes in temperature, allowing a small amount of humidity to pass to the layer underneath. This waterproofing method is recommended where the substrate is in perfect condition and does not present cracks or hairline fissures.
• System for the installation of ceramic tiles & stone material on balconies: Substrates must be structurally sound, dry, solid, and stable. Any laitance, dust, grease, oil, paint, or curing compounds present on the surface of the concrete substrate that may inhibit bond, shall be mechanically removed. Apply by brush or roller a two-component, high flexibility cementitious mortar, for waterproofing concrete surfaces. Apply thereafter a hydraulic binder for the preparation of a screed with controlled shrinkage. Apply a floor screed-leveling compound in thicknesses varying from 3mm to 80 mm. Apply on the corner joints between the floor and wall a rubber tape. Apply over the floor screed by brush or roller a two-component, high flexibility cementitious mortar for waterproofing concrete surfaces. Apply a High-performance deformable cementitious adhesive with no vertical slip and extended open time for ceramic tiles, recommended for laying large porcelain and natural stone tiles in adhesive thicknesses 3 to 15 mm. Apply as a sealing joint wherever required a high-performance, anti-efflorescence grout, polymer-modified, for joints from 2 to 20 mm solvent-free, acetic-cross-linking mildew-resistant silicone sealant.