WATERPROOFING OF ROOF GARDEN (EXISTING CONSTRUCTION)

Permanent waterproofing of roof garden (existing construction) with Penetron® integral capillary waterproofing system and with the use of polyurethane membrane Penecoat™ or with cement-based polymer-modified waterproofing coating Seal Coat™ system.

1. Repairing and waterproofing of honeycombed and spalled areas in the existing concrete slab by using the repairing mortar PENECRETE MORTAR® and the waterproofing cement-based slurry coat PENETRON®

Depending on the working procedures, the concrete surface can be cleaned and treated with high-pressure water blasting (300–500 bar), allowing better visual inspection of faulty areas.

Cracks, honeycombed and spalled areas, of new or existing concreting, should be routed out with mechanical means, to remove dirt, loose materials and aggregates. Clean honeycombed areas with excess water, to remove loose materials and moisten the surface to a dull dampness, which is prerequisite for the application of PENETRON® integral crystalline waterproofing system. When the concrete is damp, with no wet sheen on the surface, apply a slurry coat of PENETRON®, at a mixing ratio of 5 part PENETRON® powder to 3-3.5 parts of water (by volume), on the areas to be patched or repaired and 2/5” (10 mm) around them.

While PENETRON® coating is still “green” (tacky), mix PENECRETE MORTAR® with adequate amount of water, until the desired consistency is achieved [usual mixing ratio is 4.5 parts of PENECRETE MORTAR® to 1 part of water (by volume)] and filling the cracks and spalled areas. When PENECRETE MORTAR® has set, but is still moistened, apply a second layer of PENETRON® slurry coat, at a mixing ratio of 5 part PENETRON® powder to 3-3.5 parts of water (by volume), on the repaired areas. At this stage, if waterproofing of the total construction is required, apply a slurry coat of PENETRON® on the whole surface, in one layer, while the first layer is still “green” (approx. half to one hour later).

In lots of applications, to save time, the first layer of PENETRON® is applied post to surface preparation and dampening and approx. half an hour later, while the product is still “green”, the repairing mortar PΕΝΕCRETE MORTAR® is applied. Approx. half to one hour later, and while PΕΝΕCRETE MORTAR® is still “green”, the second layer of PENETRON® slurry coat is applied. The total consumption of PENETRON® is 1.1 kg/m2 in one layer.

2. Neutralization

As the application of PENETRON® products on the concrete surface cause the formation of silicic salts, not only in the concrete matrix, but most of the times on the surface of application as well, (usually after the first 48 hours since application), there is a technical issue, regarding the reduced adhesion of decorative coatings or paints. The problem is treated with the “neutralization” procedure. Neutralization is actually the good “wash” of the surface, approx. after 3 weeks, since the application of PENETRON® products (adequate time for the PENETRON® to act), with a low acidity "aggression" hydrochloric acid (HCl) aqueous solution 3-8% in content or a vinegar solution in water (at a mixing ration 1:3 to 1:10, depending on the vinegar acidity).

During the application, after the surface in cleaned with a vacuum cleaner, use a brush and a plastic pail, containing the solution for the neutralization, “wash” the surface with the solution and after a few minutes, wash the surface with excess water. Then, the surface, after it is dry, can be coated or painted. Alternatively, for the use of decorative screeds, they can be applied within the first 48 hours and before the formation of the silicic acids on the surface. In that case, the time for the coating application is minimized, but the drawback is the inability to control the correct application and operating of the system. Also, in that case, there is always a small possibility for a percent of the formed crystals to penetrate the coatings or screeds and appear on the surface.

3. Application of cementitious screed for slopes

Initially, a bonding layer is applied with PRIMER STX 100™. The cementitious screed should contain 400-500 kg cement per cubic meter. Also, PENETRON ADMIX® 0.8 – 1% per weight of cement can be added, as well as acrylic resin PENETRON® LATEX with consumption 5 – 10% by cement weight and polypropylene fibers.

4. Application of hyperelastic coating PENECOAT™ HYPER ELASTIC BLACK

Over the cementitious screed, it is applied the two components, solventbased, bitumen extended polyurethane membrane, for long lasting waterproofing, with high elasticity PENECOAT™ HYPER ELASTIC BLACK. The surface needs to be clean, dry and sound, free of any contamination, which may harmfully affect the adhesion of the primer. Maximum moisture content should not exceed 5%. Any loose surface pieces and grinding dust need to be thoroughly removed. Prime the porous substrates, such as concrete, mortars and wood, with PENEPRIMER™ PU. For non-porous substrates, such as metal, ceramic tiles, asphalt, asphalt felts and old coatings, use PENEPOX™ W. Allow primer to cure, according to its technical guidance. Apply PENECOAT™ HYPER ELASTIC BLACK A+B by brush, spike trawler or nap roller, until the surface is fully covered. Reinforcement of the entire surface with the FABRIC geotextile is recommended (in the first layer of wet product). After 12-24 hours (but no later than 72 hours), apply a second coat of PENECOAT™ HYPER ELASTIC BLACK A+B. After 24 hours, apply a third coat (sacrificial layer) of PENECOAT™ HYPER ELASTIC BLACK A+B with indicative consumption 0.5 kg/m2 and disperse dry quartz sand (QUARTZ SAND MIX grade 0.4-0.8 mm) over the surface, until the surface is fully covered, while the last coat is still damp. PENECOAT™ HYPER ELASTIC BLACK coverage is at least 1.1 – 1.5 Lt/m2, applied in one or two layers. The use of FABRIC is expected to double the PENECOAT™ HYPER ELASTIC BLACK A+B consumption per m2. This coverage is based on practical application by roller onto a smooth surface in optimum conditions. Surface porosity, temperature, humidity, application method and finishing can alter this consumption.

Alternatively, SEAL COAT™, waterproofing, ementitious base with modified polymers coating could be applied Dampen surface with clean water just prior to PENETRON® SEAL COAT™ ELASTIC ή FLEX application. Uniformly apply the first coat with a short bristle brush, making sure to fill in all surface pores and voids. PENETRON® SEAL COAT™ ELASTIC ή FLEX must be reinforced with a fiberglass grid between layers (mesh 5x5 mm) when applied between wall and floor. The next day a vertical second layer is applied. Indicative consumption for PENETRON® SEAL COAT: ~2.5 - 3 Kg/m2 The consumption depends on the roughness of the substrate and the waterproofing demands. The use of fiberglass grid is expected to increase the total coverage of the system up to approximately 3 kg/m2 in 2 layers
PENETRON® SEAL COAT™ (1 bag 22,68 kg) with the mix of 12 kg PENECRYL™ ELASTIC offers waterproofing with very good adhesion, flexibility, hyper elastic characteristics and excellent crack bridging ability. (In the product data sheet of SEAL COAT™, the system SEAL COAT™ ELASTIC is referred as system C and is described at the end of page 2 and on page 3)

5. Covering of the coating with the use of geotextile.

In the end, follows the covering PENECOAT™ HYPER ELASTIC BLACK or SEAL COAT FLEX or SEAL COAT ELASTIC, with the use of appropriate geotextile FABRIC or similar protective drainage membrane, for protection reasons.

NOTE: The above waterproofing system is called double secured safety system with the concrete slab to be protected by the integral crystalline system and by the help of the conventional waterproofing system.

The description texts mentioned above are not subject of a case study, but technical propositions, according to our best of knowledge and based on our experience and knowledge up to date. For more information, regarding the safe use, treatment and storage of our products, contact PENETRON HELLAS and refer to the Product Data Sheet and Material Safety Data Sheet of every product you use.