CELVOLIT 1318 VAE Emulsion for Polymer Cement Waterproofing Coatings

In interior wet-area tiling systems where the primary waterproofing barrier is bonded directly to the concrete substrate before thin-set mortar application, the liquid-applied cementitious slurry must form a continuous, pinhole-free film capable of resisting lateral moisture migration under intermittent wetting. Formulations based on CELVOLIT 1318 VAE emulsion, dosed to deliver a solid polymer-to-cement weight ratio (p/c) of 0.45–0.55, which equates to an as-supplied emulsion loading of 82–100 parts per 100 parts of cement at the nominal 55 % solids, are designed to meet the water-impermeability and adhesion requirements of EN 14891:2017 for liquid-applied water-impermeable products (type CM). The dry component typically comprises CEM I 42.5 N Portland cement, graded 0.1–0.3 mm silica sand, a retarder-modified cellulose ether, and a non-ionic defoamer; the liquid side is CELVOLIT 1318 pre-diluted with clean water to yield a total water-to-cement ratio of approximately 0.35. On site, material is processed in a forced-action mixer—commonly a Collomix Xo 1 with rotating pan and counter-current paddle—operated at 300–400 rpm for 3–4 minutes after powder addition to ensure full dispersion without entraining air. The resulting slump-free mortar, with a flow consistency of 140–160 mm as determined by the flow-table method of EN 1015-3, is transferred to the substrate and applied by notched trowel in two coats to a total dry film thickness of 1.5–2.0 mm; each coat is lightly rolled with a spiked aerator to release entrapped bubbles. Curing at ≥90 % RH for a minimum of 24 h is required prior to tile fixing. The compliance verification campaign includes the water-impermeability test under 0.2 N/mm² positive pressure for 24 h (EN 14891, clause 7.2) and the tensile adhesion strength test after 7 d water immersion (EN 14891, clause 7.5) where values must exceed 0.5 N/mm² with failure occurring cohesively within the coating layer. The finished product configuration is a two-component kit: a 25 kg sealed bag of powder and a 18 kg liquid pail, labelled for behind-tile waterproofing in bathrooms, shower enclosures, and domestic kitchens. Operating boundaries are substrate temperatures above 5 °C and ambient relative humidity below 85 % at the time of application; contact with reactive metals such as aluminium and zinc must be avoided due to alkaline hydrogen evolution. The polymer film formation, which proceeds as the cement hydrates and water is consumed, delivers the necessary flexibility and adhesion, but exposure to freezing before the mortar reaches a compressive strength of 5 N/mm² can cause irreversible film disruption and loss of waterproof integrity.

When Temperature Fluctuations Exceed 40 °C and Crack-Bridging Becomes Mandatory

Exposed balcony decks and roof terraces subject to diurnal thermal swings greater than 40 °C and structural movement demand polymer-cement waterproofing membranes capable of bridging cracks that open and close under service conditions. CELVOLIT 1318-based formulations targeting the EN 14891:2017 crack-bridging class CB II (crack-bridging ability ≥0.75 mm at −5 °C, per clause 7.6) are adjusted to a solid polymer-to-cement weight ratio in the range 0.90–1.10, corresponding to an emulsion addition of 164–200 parts by weight per 100 parts of cement. The dry blend incorporates early-strength CEM I 52.5 N cement, graded 0.06–0.2 mm silica filler, and a small fraction of 0.5 mm maximum aggregate to limit shrinkage, while the liquid side relies on the CELVOLIT 1318 latex diluted to maintain a total w/c of 0.30–0.32. Production-scale application utilises continuous mixing pumps—such as a PFT G4 or Putzmeister MP 25 equipped with a DN 35 hose and spray gun—that blend the pre-batched liquid component with the powder, convey the slurry over distances up to 30 m, and spray a wet coat of 1.0–1.5 mm per pass. Between coats, an alkali-resistant glass fibre mesh (mesh opening 4×4 mm, weight ≥160 g/m²) is embedded to provide mechanical reinforcement against crack propagation. A total dry film thickness of 2.5–3.0 mm is built up in two or three applications; the mortar must not skin over in less than 15 minutes at 25 °C to allow proper mesh embedding. Curing proceeds for 48–72 h at >80 % RH, after which a flexible tile adhesive compliant with EN 12004 C2 S1 is installed over the membrane. Beyond crack bridging, the system is verified for tensile adhesion after freeze-thaw cycling according to EN 13687-4, requiring values above 0.5 N/mm², and for water impermeability under 0.2 N/mm² positive pressure for 7 d (EN 14891 clause 7.2). The commercial package is a two-component kit with 25 kg powder and 20 kg liquid pail, classified as a flexible waterproofing coating for exterior balconies, terraces, and walkways. Operational restrictions include a maximum substrate temperature of 30 °C during application to prevent rapid water evaporation and skinning, an interdiction to expose the uncured membrane to direct UV radiation for more than 14 d—the VAE polymer embrittles under prolonged actinic exposure—and the necessity to protect the freshly applied coat from rain for a minimum of 6 h to avoid wash-out of the unhydrated cement.

Permanent immersion in chlorinated water, with residual free chlorine concentrations maintained between 1.0 and 3.0 mg/L and pH 7.2–7.6, establishes a chemically aggressive environment that accelerates calcium hydroxide leaching and can hydrolyse ester groups in vinyl acetate copolymers if the coating is under-cured. Polymer-cement waterproofing membranes for swimming pool shells formulated with CELVOLIT 1318 operate at a solid p/c of 0.65–0.85, or an emulsion dose of 118–155 parts per 100 parts of cement, balancing low capillary porosity with sufficient polymer coalescence to resist chlorine attack. The powder fraction is built from sulfate-resisting cement (CEM I 42.5 R-SR, EN 197-1) blended with microsilica (5–7 wt% of binder) and calcined bauxite filler to mitigate sulfate-induced expansion and to densify the pore structure; the liquid component is CELVOLIT 1318 diluted to a total w/c of 0.33. Mixing is performed in a slow-speed planetary mixer for 5 minutes after the initial wetting phase, and the mortar is forced-fed into the concrete substrate pores using a sharp-edged stainless steel trowel in the first pass, followed by a flat trowel finish in the second pass to close the surface; total dry thickness is 2.0 mm. After 7 d of moist curing under wet hessian, the coating is sponge-floated to obtain a non-porous finish that minimises biofilm adhesion. Compliance with EN 1504-2:2004, principles 1.3 and 6.1, is demonstrated through water absorption <5 % per EN 1062-3, capillary water absorption <0.1 kg/(m²·h⁰·⁵) per EN 13057, and adhesion on saturated concrete ≥0.8 N/mm² per EN 1542. For drinking water contact in combined pool/tank applications, additional testing under EN 14944-1:2006 is required, with the total organic carbon migration limit set at 2.5 mg/L. The end product is supplied as a 20 kg liquid component and 25 kg powder component kit, approved for use in public and private swimming pool shells, splash-water channels, and water reservoirs. Process boundaries dictate that application be avoided when water temperature is below 10 °C; moreover, ozone-based disinfection shocks that raise dissolved ozone above 0.5 mg/L must not occur within the first 28 d of curing, as residual peroxide species can oxidise the polymer film and reduce adhesion.

Negative-Side Hydrostatic Pressure Resistance in Subterranean Retaining Walls

Basement retaining walls accessed only from the interior impose a stringent requirement: the waterproofing membrane must resist hydrostatic pressure acting on its reverse face—negative-side water pressure—while remaining fully bonded to a substrate that is often permanently damp. CELVOLIT 1318 polymer-modified mortars employed for this service rely on a solid p/c of 0.55–0.75 (100–136 parts emulsion per 100 parts cement) to enhance adhesion under moisture-saturated conditions and to lower the modulus of the cured matrix, thereby accommodating minor substrate movements without debonding. The dry component combines rapid-hardening CEM I 52.5 R with finely ground granulated blast-furnace slag (20 % replacement) to reduce heat of hydration and minimise early shrinkage cracking. Mixing is executed in a heavy-duty paddle mixer at low speed (300 rpm) for 4 min, and the slurry must be applied within a pot life not exceeding 45 min at 20 °C. Before coating, the concrete substrate is prepared by dry grit blasting to an ICRI surface profile CSP 3; a bonding primer consisting of the liquid component diluted to p/c 0.30 and brushed in a thin film is allowed to become tacky. The main waterproofing body is then trowelled in two layers to a total dry thickness of 2.5 mm, with the first coat vigorously compacted into the profile. Curing is conducted by covering with water-saturated, non-bleeding hessian for a minimum of 5 d; any drying during this period will result in tensile adhesion values below the threshold of 0.8 N/mm² required by EN 1542 when tested after 7 d water immersion. Performance against negative hydrostatic pressure is evaluated by a modified water-penetration test following EN 12390-8: the coating, applied to a concrete slab and subjected to 0.5 N/mm² water pressure for 72 h, must restrict the penetration depth to less than 20 mm. Compliance with EN 1504-2:2004 surface protection products is mandatory, and the system is classified under principle 1.3 for water impermeability and 6.1 for resistance to moisture. The product is commercialised as a two-component kit comprising 25 kg bagged powder and 18 kg liquid, designated for interior-applied waterproofing of basement walls, lift pits, and underground car park retaining structures. Incompatibilities exist with active water-running cracks—these must be pre-injected with hydrophobic polyurethane resin—and with substrates having a moisture content above the saturated surface-dry condition, as the bonding primer cannot adequately penetrate water-filled capillaries. The coating must be protected from sub-zero temperatures for at least 72 h after application, and exposure to early hydrostatic loading before 14 d of curing can cause blistering and detachment.

Drinking water contact surfaces require a demonstrably low leaching profile governed by EN 14944-1:2006 and the European Acceptance Scheme for construction products in contact with water intended for human consumption. Cementitious waterproofing coatings for potable water storage tanks using CELVOLIT 1318 as the polymer binder are formulated at a restricted solid p/c of 0.40–0.50 (73–91 parts emulsion per 100 parts cement) to minimise the organic fraction that contributes to soluble total organic carbon (TOC) while retaining adequate water-impermeability. The powder mass comprises white Portland cement (CEM I 52.5 N, low in Cr^VI), and an inert limestone filler (CaCO₃ >98 %) to control the rheology and reduce the alkali background; no cellulosic thickening agents are used that could serve as nutrients for microbial growth. The liquid component is CELVOLIT 1318 diluted with deionised water to a total w/c of 0.35. The mortar is prepared in a clean stainless-steel planetary mixer with PTFE-coated paddles, mixed for 4 min, and applied by medium-stiff nylon-bristle brush in three layers to a cumulative dry film thickness of 1.5 mm. Between successive coats, a minimum 12 h curing interval at >95 % RH is observed to prevent delamination and to allow full hydration of the cement at the interface. After the final coat, curing is extended for 14 d under moist conditions before water can be stored. Conformity assessment includes the migration test for TOC (EN 14944-1, Annex B) with a pass limit of 2.5 mg/L and for specific organic substances per the positive list of the applicable national regulation. Adhesion on saturated concrete must still exceed 0.8 N/mm² per EN 1542. The terminal product is a two-component kit in 20 kg and 20 kg packaging, bearing a formal certificate of conformity for drinking water contact, and is specified for rehabilitation and new construction of concrete service reservoirs, clear water tanks, and treatment basins. Operational boundaries are critical: the carbonate-rich coating must be shielded from carbon dioxide exposure during the first 14 d because rapid carbonation reduces pH and solubilises the polymer-cement interphase; water with a Langlier Saturation Index below −0.5 should not be stored unless the cement matrix has been fully carbonated and re-passivated; and the contact water pH must remain above 6.8 to avoid progressive lime leaching that increases porosity and TOC release.

What Limits the Wet-Adhesion Retention of Polymer-Modified Cementitious Slurries on Damp Concrete in Elevator Pit Sumps?

Elevator pits and industrial sumps present a severe environment in which the waterproofing lining is constantly exposed to standing water, intermittent oil contamination, and limiting access for surface preparation. The ability of CELVOLIT 1318-modified mortars to maintain wet adhesion on permanently damp concrete is governed by the polymer-cement ratio and the film coalescence mechanism under high humidity. Formulations for this duty adopt a solid p/c of 0.70–0.90, translating to an emulsion addition of 127–164 parts per 100 parts cement, which yields a continuous polymer network that accommodates the osmotic pressure at the cement-polymer interface during prolonged water immersion. The powder base is a blend of CEM I 42.5 N with fly ash (15 %) and a combination of quartz flour and 0.2–0.5 mm aggregate to improve crack resistance. In the field, the two-component mix is combined with a hand-held paddle mixer operating at 600 rpm and must be placed within a working time of 30 min when ambient temperature reaches 30 °C. After substrate cleaning to remove laitance and oil residues, a thin scratch coat is scrubbed into the saturated surface, immediately followed by embedding an alkali-resistant glass fibre mesh (80 g/m²), and then a top layer applied at 90 min interval to a total dry thickness of 3.0 mm. Wet adhesion is evaluated according to EN 1542 after 7 d water immersion, with a minimum required pull-off strength of 0.8 N/mm²; failure mode must be cohesive in the substrate or the coating. A complementary test per EN 14891 for water impermeability under 0.2 N/mm² for 7 d confirms zero leakage across the lining. The system is not suited for substrates heavily contaminated with mineral oils: a preliminary coating of a two-component epoxy primer is mandatory when oil stains remain after mechanical cleaning. The finished product type remains the standard two-component kit, labelled for waterproofing sumps, cable trenches, elevator pits, and other subsurface utility structures. Exposure to vehicle traffic or mechanical loads is permissible only after a curing period of 7 d at a compressive strength of at least 20 N/mm², and the lining must be protected from freezing for the first 72 h; residual water ponding on the surface during the initial 24 h of curing must be removed to prevent polymer skin at the surface that becomes soft on re-wetting.