About MC-Bauchemie MC-Protect 1K

MC-Protect 1K is MC-Bauchemie’s answer to a recurring site headache: two-part cementitious systems that go wrong when a crew mis-measures the liquid-to-powder ratio in the heat of a pour schedule. By pre-blending the polymer binders, waterproofing additives, ordinary Portland cement and graded aggregates into a single dry powder, the product removes that variable entirely. The applicator adds only clean water, which means every batch on a large basement or reservoir job carries the same engineered dosage. For contractors managing multiple gangs across a site, that repeatability is often worth as much as the raw performance figures.

The coating works on two fronts. The polymer modification gives it flexibility and a strong mechanical grip on concrete and masonry, developing a pull-off bond of more than 1.5 MPa on a properly prepared substrate. Alongside that, crystalline components in the mix react with free calcium hydroxide from cement hydration to grow insoluble calcium silicate hydrate crystals inside the pore structure and hairline capillaries. This is what lets a relatively thin coat hold back water not just from the wet face (positive side, tested to around 7 bar) but also from the dry face (negative side, to around 3 bar) — a genuine advantage when you can only reach a leaking basement wall from the inside.

The technical insight

The performance comes from two mechanisms working together rather than one. First, the acrylic-style polymer binder films the cement matrix as it cures, adding tensile flexibility and creating an intimate, high-adhesion bond to the substrate — this is why the coating resists delamination and can survive the pressure trying to push it off the wall on the negative side. Second, and less visible, is the crystalline reaction: soluble active compounds migrate through the moisture already present in the concrete and react with calcium hydroxide to precipitate needle-like CSH crystals that physically block capillary pores. Because that reaction is water-driven, the sealing tends to reactivate whenever moisture reappears, giving the treated concrete a degree of self-sealing against fine capillary tracking. The practical takeaway for a specifier is that MC-Protect 1K does not merely sit on the surface as a barrier film; it partly integrates into the top layer of the concrete itself, which is why it tolerates negative-side hydrostatic pressure that would lift a purely superficial membrane.

Where it is used

• Positive-side (external) tanking of underground basement rafts and retaining walls before backfill
• Negative-side (internal) waterproofing of basement walls where the external face is inaccessible
• Overhead and underground potable-water storage tanks and reservoirs
• Swimming pool shells, balancing tanks and water features
• Sewage treatment structures, wet wells and effluent tanks
• Planter boxes, terrace gardens and landscaped decks over occupied space
• Lift pits, machine foundations and buried service ducts
• Metro, utility and cable tunnels requiring a bonded cementitious seal

Key advantages

• Single-pack, just-add-water format eliminates on-site ratio errors and speeds up batching
• Works against both positive and negative hydrostatic pressure, so inaccessible faces can still be sealed
• Crystalline action seals capillaries within the concrete and reactivates on renewed moisture contact
• High pull-off bond exceeding 1.5 MPa keeps the coating fixed to the substrate under pressure
• Formulated for potable-water contact, suiting drinking-water tanks and reservoirs
• Applies by brush, trowel or spray, giving flexibility across geometries and access conditions
• Cementitious base breathes with the structure and bonds without a separate primer on sound concrete
• Backed by MC-Bauchemie’s international quality control and Space Arc’s local technical support

Limitations & considerations

• It is a rigid-to-semi-flexible cementitious coating; it is not designed to bridge live, moving cracks or expansion joints, which need a dedicated elastomeric or joint system
• The substrate must be structurally sound, clean and brought to a saturated-surface-dry condition — poor preparation is the most common cause of failure
• Curing depends on retained moisture; hot, windy or highly absorbent conditions call for pre-wetting and protection from rapid drying
• Potable-water suitability requires the batch and application to meet the applicable local certification, which should be confirmed for the project
• As a thin coat it does not compensate for structural water paths, honeycombing or active leaks, which must be plugged or grouted first

Selection & best practice

Specifications

Industry use cases

How we position MC-Bauchemie MC-Protect 1K

MC-Protect 1K sits in the single-component, positive-and-negative cementitious tier of the waterproofing range — the practical default when a project values batching simplicity, potable-water suitability and negative-side capability. Where a job needs greater flexibility and crack accommodation, MC-Bauchemie’s flexible two-component sealing slurries in the MC-Proof / Zentrifix family are the natural step up, and for admixture-based integral protection the Centrament waterproofing admixtures complement the coating from within the concrete. Across our other brands, we would pair or contrast it with two-pack acrylic membranes such as Fosroc Brushbond and Dr. Fixit’s cementitious coatings where a client already specifies those systems, and with polyurethane or bituminous membranes from Sika and STP for exposed, high-movement or terrace applications where a rigid cementitious coat is not the right tool. Our role at Space Arc is to match the mechanism to the exposure rather than push a single product.

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