MC-Flex 1K
Single-Component Polyurethane Liquid Waterproofing Membrane for Roofs, Terraces, Balconies, and Wet Areas
Authorized Project Distributor — MC-Bauchemie India | Space Arc Engineering, Ghaziabad
Product Overview
MC-Flex 1K is a single-component, moisture-curing, liquid-applied polyurethane elastomeric waterproofing membrane from MC-Bauchemie used for the waterproofing of flat roofs, terraces, podiums, balconies, drainage channels, and wet rooms in residential, commercial, and industrial buildings. Unlike traditional bituminous or modified bitumen sheet membranes that require flame torch application (creating fire hazard on occupied buildings), or two-component polyurethane systems that require precise on-site mixing, MC-Flex 1K is supplied ready-to-use in sealed drums or containers and cures by reaction with atmospheric moisture — the same principle as moisture-curing polyurethane joint sealants — to form a permanently elastic, seamless polyurethane membrane bonded directly to the prepared substrate. The single-component moisture-curing system eliminates the mixing ratio errors and incomplete curing problems that can occur with two-component PU systems, and allows application by simple brush, roller, or airless spray without specialist mixing or dosing equipment. The cured MC-Flex 1K membrane is a fully elastic, rubber-like material with elongation at break of 200 to 400 percent — substantially higher than cementitious or bituminous coatings — which allows it to bridge and accommodate active cracks and movement joints in the concrete substrate without cracking through. This crack-bridging elongation is the critical advantage of polyurethane membranes over rigid waterproofing coatings for roof and terrace applications in the Delhi NCR climate: the large seasonal temperature differential (5 to 7 degrees C in January versus 45 to 50 degrees C concrete surface temperature in May and June on an exposed rooftop) drives significant thermal movement in the concrete slab, and any rigid waterproofing coating will crack at stress concentrations — re-entrant corners, upstands, drain flanges, and parapet junctions — as the concrete moves beneath it. The elastic polyurethane membrane of MC-Flex 1K stretches and contracts with the concrete movement without cracking. Space Arc Engineering supplies MC-Flex 1K for waterproofing contractors, building material dealers, and building renovation specialists across Ghaziabad, Delhi NCR, Noida, and Uttar Pradesh.
Applications
- Flat roof and terrace waterproofing — seamless liquid-applied polyurethane membrane for residential and commercial building exposed roof slabs
- Balcony and podium waterproofing — crack-bridging elastic membrane under tile bedding for balcony and elevated podium slab waterproofing
- Drainage channel and gutter lining — seamless, flexible PU membrane lining for precast or in-situ concrete drainage channels and valley gutters
- Wet room and bathroom waterproofing — elastic liquid-applied membrane under ceramic tile for bathrooms, showers, and kitchen splash areas
- Green roof and planter box waterproofing — root-resistant PU membrane for planted roof and balcony planter box applications
- Podium deck and parking deck waterproofing — heavy-duty PU membrane system for trafficked podium decks over occupied basement areas
Key Advantages
- Single-component — no mixing required, no pot-life risk, no operator error — simple consistent membrane from drum to surface
- Seamless and joint-free — liquid-applied membrane covers complex geometry including drains, upstands, corners, and penetrations without joints
- High elongation — 200 to 400 percent elongation at break bridges active cracks and accommodates thermal movement without membrane cracking
- No flame or heat application — moisture-curing system — no fire risk on occupied buildings, no hot works permit required
- UV-stable topcoat available — UV-reflective or coloured topcoat (silver, grey, red) for exposed roof membrane protection and solar reflectance
- Vapour-permeable formulations available — allows concrete substrate to breathe while maintaining waterproofing — reduces osmotic blistering risk
Technical Data
| Type | Single-component moisture-curing aromatic or aliphatic polyurethane liquid-applied waterproofing membrane |
| Application Thickness | 1.0 to 1.5 mm dry film thickness minimum — applied in 2 to 3 coats at 0.4 to 0.6 kg per square metre per coat |
| Elongation at Break | 200 to 400 percent — permanently elastic after full cure — accommodates active crack movement and thermal displacement |
| Tensile Strength | Greater than 1.5 MPa at break — adequate tensile capacity for movement accommodation and mechanical resistance |
| Curing Rate | Tack-free in 2 to 4 hours — rain-resistant in 6 to 8 hours — fully cured in 3 to 7 days depending on temperature and humidity |
| Conformance | EN 14891 (Liquid-applied bridge membranes — hydraulically bonded) — ASTM D6134 (Standard Specification for Vulcanized Rubber Sheets) |
Get a Quote
+91 9999155255 | info@space-arc.com | Space Arc Engineering, Sahibabad, Ghaziabad
Frequently Asked Questions
For waterproofing a flat RCC terrace of a residential building in Ghaziabad that has existing cracks and failed bituminous felt waterproofing, should a contractor strip out the old felt and replace it with MC-Flex 1K polyurethane membrane, and what preparation and application procedure should be followed?
Waterproofing renovation of a flat RCC terrace with failed bituminous felt in a Ghaziabad residential building is a very common assignment for waterproofing contractors, and MC-Flex 1K liquid-applied polyurethane membrane is an excellent choice for this application — it can be applied over prepared concrete substrate after stripping the failed felt, or in some cases can be applied over sound, well-bonded existing felt, eliminating the need for full stripping. The decision on whether to strip the failed felt or overlay it depends on the condition of the existing felt: if the existing felt is blistered, debonded, extensively torn, or has multiple layers of old felt and bituminous coating that together form an unstable, irregular surface, it should be completely stripped. If the existing felt is generally in contact with the substrate with only localised debonding at cracks and upstands, it may be possible to cut out the debonded sections, remove them, fill the voids with repair mortar, and overlay the repaired surface with MC-Flex 1K — subject to trial adhesion testing. The following procedure covers the full strip and MC-Flex 1K replacement scenario for a typical Ghaziabad terrace. Strip existing waterproofing: remove all existing bituminous felt, modified bitumen sheets, lime mortar, and any loose or debonded concrete surface by mechanical scraping, chipping, or disc grinding. Remove all material to expose the solid concrete deck surface. Substrate repair: inspect the exposed concrete deck for cracks, surface defects, and spalling. All cracks wider than 0.3 mm should be routed (cut to 5 to 10 mm width by 10 to 15 mm depth using an angle grinder with crack chaser disc) and filled with MC-Seal 180 polyurethane joint sealant to provide a flexible crack seal within the waterproofing system. Surface irregularities, honeycombing, and blowholes should be filled with MC-RocTec 222 F repair mortar to produce a smooth, even surface. The entire terrace deck must be swept, vacuumed, and blown clean of dust. Critical detail areas: apply a reinforcing fleece (polyester or glass fibre fleece mat, 100 to 150 g per square metre) embedded in the first coat of MC-Flex 1K at all detail areas that are prone to failure: drains (200 mm radius around each drain outlet), upstand and parapet junctions (300 mm wide strip from horizontal surface up the vertical upstand), re-entrant corners (100 mm wide strip at each internal corner), and any repaired cracks. The fleece reinforcement in these areas provides a crack-bridging layer that prevents point stress concentrations from causing membrane tears at detail terminations. Primer application: apply MC-Bauchemie or recommended PU-compatible primer to the entire concrete deck surface at the specified coverage rate by roller — allow to dry tack-free (typically 1 to 2 hours) before first membrane coat. For porous or dusty concrete substrates, two primer coats may be required to achieve a sealed, low-porosity primed surface. First membrane coat: apply the first coat of MC-Flex 1K at 0.5 to 0.6 kg per square metre by brush or roller in a single direction, ensuring full coverage of all primed surfaces and careful working of the membrane into all corners, upstands, drain flanges, and penetrations. At detail areas, embed the reinforcing fleece into the wet first coat and brush over to fully encapsulate the fleece in membrane material. Allow the first coat to cure until tack-free (2 to 4 hours at 25 degrees C, longer in humid conditions). Second and third membrane coats: apply subsequent coats at right angles to the previous coat direction at 0.5 to 0.6 kg per square metre per coat, achieving a total wet film thickness corresponding to a minimum 1.5 mm dry film thickness (measured with a wet film thickness comb during application or confirmed by weighing the applied material). A total of 2 to 3 coats is typically required. In hot conditions (above 35 degrees C), do not apply MC-Flex 1K in direct afternoon sunlight when the concrete surface temperature exceeds 40 degrees C — schedule application for early morning. UV protection topcoat: MC-Flex 1K is formulated with aromatic diisocyanate chemistry (standard for most single-component moisture-curing PU membranes) and will yellow and chalk on prolonged UV exposure if left unprotected. Apply a UV-stable aliphatic polyurethane topcoat or aluminium reflective coating over the cured MC-Flex 1K membrane at the specified rate to provide UV protection and extend membrane service life. For exposed terraces in Ghaziabad, a solar-reflective silver or light grey topcoat also provides significant reduction in roof surface temperature (reducing heat island effect and solar heat gain into the building below). Space Arc Engineering provides MC-Flex 1K, associated primers, fleece reinforcement, and UV topcoat supply, and technical support for terrace and roof waterproofing renovation projects across Delhi NCR, Ghaziabad, Noida, and Uttar Pradesh.
Source MC-Flex 1K for Your Project
Space Arc Engineering is an Authorized Project Distributor for MC-Bauchemie India serving Delhi NCR, Ghaziabad, Noida and Uttar Pradesh.
Get MC-Flex 1K — Single-Component Polyurethane Liquid Waterproofing Membrane for Roofs, Terraces, Balconies, and Wet Areas — pricing, TDS & technical help
Space Arc Engineering is an authorized MC-Bauchemie distributor & applicator in Delhi NCR & pan-India. Fast quotes, datasheets and on-site support.
Get a Quote on WhatsAppRequest TDS on WhatsAppRelated waterproofing products
Other waterproofing systems we supply & apply across Delhi NCR and pan-India.