MC-Bauchemie Emcephob SX / AC
MC-Bauchemie’s breathable silane-siloxane impregnation and UV-stable topcoat system that keeps water, chlorides and carbonation out of exposed concrete and masonry facades — without sealing or discolouring the surface.
What is it?
A two-part MC-Bauchemie water-repellent system for concrete and masonry: Emcephob SX is a colourless, non-film-forming silane-siloxane impregnation, and Emcephob AC is a transparent, film-forming siloxane-acrylate topcoat with high UV stability.
Where is it used?
Exposed RCC facades, masonry and brick elevations, precast cladding, parapets, balconies, bridge piers and heritage stonework — anywhere a vertical or exposed mineral surface needs to shed water without being sealed or visually altered.
Why use it?
It blocks capillary water and salt ingress — the drivers of carbonation- and chloride-induced rebar corrosion — while staying breathable, so trapped moisture inside the wall can still escape instead of being sealed in behind a film.
How is it applied?
Emcephob SX is worked into the surface by low-pressure spray, brush or roller to visible saturation; once it has penetrated and dried tack-free, Emcephob AC is applied over it as a uniform film coat where UV and weathering resistance is also needed.
About MC-Bauchemie Emcephob SX / AC
MC-Bauchemie brought Emcephob SX and Emcephob AC to the Indian market as a two-part answer to a problem every RCC facade in the country eventually faces: water finds its way in, and once it does, it carries carbonation and chloride ions straight to the rebar. Emcephob SX is the workhorse of the pair — a colourless, solvent-based silane-siloxane impregnation that soaks into the capillary pores of concrete, mortar and masonry and lines them with a hydrophobic layer. It doesn’t sit on the surface as a film; it dries tack-free and disappears into the substrate, which is exactly why specifiers reach for it on facades where changing the look of the building isn’t an option. What makes it worth specifying over a generic silane product is its alkali resistance, which MC-Bauchemie rates as especially high — useful on younger concrete that’s still carrying a high pH, where lesser impregnations can break down early.
Emcephob AC is the companion coat, and it does a different job. Built as a siloxane-acrylate combination, it forms an actual transparent film with strong UV stability, so where SX blocks water at the pore wall, AC adds a weatherable skin on top that shrugs off years of sun without chalking or yellowing. Used together — SX first to penetrate and protect, AC over it to seal and weather — you get a combination system that’s breathable (water vapour still escapes, so you’re not trapping moisture behind a membrane) but far more resistant to driving rain, salt spray and UV than either product alone. Space Arc supplies and applies this system across Delhi NCR and pan-India projects on exposed RCC, masonry facades and heritage stonework, and it’s one of the more honest products in the water-repellent category precisely because it doesn’t pretend to be a waterproofing membrane — it’s a facade protection system, and it’s very good at that specific job.
The technical insight
The distinction that matters most between SX and AC is film versus no film, because that’s what governs breathability. Emcephob SX works by lining the internal pore walls of the concrete with a hydrophobic layer — the pore stays open, water vapour can still move through it, but liquid water beads and rolls off instead of being drawn in by capillary action. That’s fundamentally different from a coating that sits on top and physically blocks the pore mouth; because nothing bridges the surface, there’s no film to crack, peel or trap vapour pressure behind it, which is exactly why silane-siloxane impregnations are the standard answer for facades where the substrate needs to keep breathing. Emcephob AC deliberately trades some of that invisibility for durability: its acrylate component builds an actual transparent film over the siloxane, and that film is what gives it the extremely high UV resistance MC-Bauchemie claims — an impregnation alone has nothing to protect against ultraviolet degradation, but a film can be formulated to resist it. Run them as a system and you get a substrate that’s hydrophobic all the way into its pore structure from the SX pass, with a weatherable, UV-stable skin from the AC pass sitting on top of that. The alkali resistance callout on SX is worth taking seriously in Indian conditions specifically: a lot of facade impregnation failures aren’t UV failures at all, they’re the product breaking down under the sustained high pH of concrete that hasn’t fully carbonated at the surface yet, and that’s the exact failure mode SX is formulated against.
Where it is used
- Fair-faced and exposed architectural RCC facades where the natural concrete finish must be preserved
- Brick and stone masonry facades, including heritage structures where breathability is non-negotiable
- Exposed balconies, parapets, chajjas and sunshades that take direct rain
- Precast concrete cladding panels and architectural elements
- Bridge piers, parapets and other exposed RCC elements in coastal or industrial (high-chloride/sulphate) environments
- External face of basement or retaining walls above grade, as back-of-wall protection before backfilling
- Sun-exposed concrete and masonry facades where UV-driven coating breakdown is a recurring maintenance problem
Key advantages
- Breathable protection — water vapour trapped inside the wall can still escape, unlike a film-forming membrane that seals moisture in
- Emcephob SX penetrates into the capillary pore structure rather than forming a surface skin, so it blocks water at the source without altering the concrete’s texture
- Especially high alkali resistance on the SX component means it holds up on fresher, high-pH concrete where ordinary silane treatments can degrade early
- Emcephob AC’s siloxane-acrylate film carries extremely high UV resistance, so sun-facing facades don’t chalk or lose protection as fast as with acrylate-only coatings
- Cuts the rate at which water and chloride/carbonation-carrying moisture reach the rebar, which is the real long-term saving — corrosion repair costs far more than the impregnation itself
- Improves resistance to frost-spalling and freeze-thaw distress on exposed concrete and masonry
- Emcephob SX alone leaves the substrate visually unchanged, so it’s the safer starting point on heritage or fair-faced work where an owner won’t tolerate any colour shift
- Roller, brush or low-pressure spray application means no heavy plant or specialised crew — a trained waterproofing applicator can handle it
Limitations & considerations
- Not a substitute for a waterproofing membrane — it won’t bridge structural cracks or hold up under ponding water or hydrostatic pressure
- Emcephob AC’s film-forming nature causes a visible wetting/darkening effect on application, which some owners find unacceptable on fair-faced work — always trial first
- Effectiveness depends entirely on substrate porosity; painted, previously sealed, oil-contaminated or heavily laitance-covered surfaces won’t take up the impregnation properly
- Won’t stop active water ingress through open structural cracks — those need to be repaired or injected before this system is applied
- As a UV-exposed surface film, Emcephob AC will need periodic recoating over the building’s life; it is a maintained protection system, not a one-time application
- Not intended for constantly submerged or below-grade positive-hydrostatic-pressure conditions
Selection & best practice
Substrate condition decides the outcome here more than anything in the tin. The surface has to be sound, clean, dry and free of laitance, curing compound, algae, paint or any prior sealer — porosity is what makes the impregnation work, and a sealed or painted surface simply won’t take it up. Run a water-absorption check on a test patch first, and always do a small trial application before committing to the full facade, because Emcephob AC’s wetting effect changes the appearance the moment it goes on, and that’s not something you want to discover on the client’s front elevation. Apply Emcephob SX generously — to visible saturation, working wet-on-wet if a second pass is needed — by low-pressure airless spray, brush or roller, and give it the dry time MC-Bauchemie’s applicator instructions call for before topcoating. Apply Emcephob AC as a uniform film without pooling or runs, and keep the treated surface protected from rain during the cure window; a shower within a few hours can wash out an otherwise sound application. Mask glazing, anodised aluminium and any surface you don’t want treated — siloxanes are difficult to remove once cured. And set expectations with the client up front: this is a facade protection system with a recoat cycle, not a one-time, forever fix.
Specifications
| Emcephob SX chemistry | Silane-siloxane impregnation, colourless and transparent, non-film-forming |
| Emcephob AC chemistry | Siloxane-acrylate combination, transparent, film-forming |
| Alkali resistance (SX) | Especially high — suited to fresh, high-pH concrete and mortar |
| UV resistance (AC) | Extremely high — formulated for sun-exposed facades |
| Surface finish | SX dries tack-free with no visual change; AC forms a film with a wetting/darkening effect on application |
| System configuration | Two-coat combination system — SX as penetrating base coat, AC as protective UV-stable topcoat |
| Substrate types | Mineral substrates — concrete, mortar and masonry |
| Manufacturer category | Listed under Waterproofing > Water Repellent Systems and Hydrophobic Agents & Impregnation on mc-bauchemie.in |
Industry use cases
Residential high-rise, Delhi NCR
SX/AC applied to exposed RCC columns and facade bands on a cover-deficient elevation to slow carbonation ingress and control monsoon staining without changing the architect’s exposed-concrete finish.
Heritage conservation
Emcephob SX used alone on sandstone and lime masonry restoration work, chosen specifically because it leaves the stone breathable and visually unchanged — a hard requirement on protected heritage facades.
Coastal industrial facility
Precast concrete cladding treated with the full SX/AC system to resist combined UV exposure and chloride-laden sea air, where a film-only coating would have failed faster under salt spray.
Highway infrastructure
Exposed parapets and pier faces on an elevated corridor treated to reduce chloride and carbonation ingress into cover concrete, cutting long-term rebar corrosion risk on structures that are expensive to access for repair.
Basement/retaining wall
External face of a retaining wall treated with Emcephob SX above the primary membrane line as supplementary back-of-wall protection before backfilling.
Frequently asked questions
Do I need to apply both Emcephob SX and Emcephob AC, or can I use just one?
Will Emcephob AC change the colour or look of my concrete?
Can Emcephob SX/AC replace a waterproofing membrane on my terrace or roof?
How often does the coating need to be reapplied?
Can it go over existing paint or a previous sealer?
Is it suitable for newly cast, green concrete?
How we position MC-Bauchemie Emcephob SX / AC
Within MC-Bauchemie’s own India range, Emcephob SX/AC sits alongside a broader hydrophobic-impregnation family — Emcephob HC, Emcephob WM, the Emcephob NanoPerm P/T pair and Emcephob LE — each tuned for slightly different substrates and exposure levels, so a specifier already on the Emcephob line should check whether SX/AC or one of those siblings is the better pore-size and exposure match before defaulting to this one. Against the wider market, the closest genuinely comparable products are Sika’s Sikagard-705 L and Sikagard-706 Thixo silane-siloxane impregnations, and on the Fosroc side, Nitocote SN522 — a single-component penetrating silane-siloxane that competes directly with Emcephob SX where a project wants one product rather than a two-coat system, or is already standardised on Fosroc. Space Arc’s honest read: choose Emcephob SX/AC where the two-coat, alkali-resistant-plus-UV-stable combination is worth the extra application step; choose a single-component alternative like Nitocote SN522 where the brief is simpler impregnation without the topcoat.
Fosroc Nitocote SN522 — A specifier who wants a single-component penetrating silane-siloxane impregnation without committing to a two-coat system, or who is already standardised on Fosroc across a project, would reach for Nitocote SN522 as the closest functional match to Emcephob SX on its own.
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