Protect your terrace. Prevent water seepage. Extend the life of your concrete structure.

FEMCO provides cementitious terrace waterproofing solutions using polymer-modified cementitious coatings reinforced with a continuous single layer of alkali-resistant fibreglass reinforcement.

This application method combines the bonding and waterproofing properties of polymer-modified cementitious materials with the tensile reinforcement of fibreglass mesh, helping create a continuous protective barrier over the concrete terrace.

Whether it is a residential terrace, commercial rooftop, industrial building or RCC roof slab, proper surface preparation and systematic application are essential for long-term waterproofing performance.

Why does your terrace need waterproofing?

Terraces are continuously exposed to:

• Rainwater and prolonged water exposure.

• Direct sunlight and temperature fluctuations.

• Expansion and contraction of concrete.

• Hairline cracks and shrinkage cracks.

• Water seepage through concrete pores and weak joints.

• Deterioration of the concrete surface over time.

Water penetration can result in damp ceilings, peeling paint, plaster damage, corrosion of reinforcement and deterioration of the building structure.

A properly executed waterproofing treatment helps minimise these risks.

STEP 01 – Inspection of the existing terrace

Before commencing work, the terrace is thoroughly inspected to identify:

• Existing cracks and structural joints.

• Loose or damaged concrete.

• Existing waterproofing layers, if any.

• Low-lying areas where water accumulates.

• Drainage outlets and rainwater pipes.

• Junctions between the terrace slab and parapet walls.

• Pipe penetrations and other service openings.

The condition of the existing substrate determines the extent of surface preparation and repair required.

STEP 02 – Surface cleaning and preparation

The entire terrace surface is cleaned to remove dust, dirt, algae, moss, loose cement particles, oil, grease and deteriorated coatings.

Mechanical wire brushing, scraping or grinding is carried out wherever necessary.

The surface is then cleaned using water or suitable cleaning equipment.

Loose and weak concrete must be removed until a sound substrate is exposed.

Objective: To ensure proper adhesion between the existing RCC surface and the new waterproofing system.

STEP 03 – Crack treatment and concrete repairs

All visible cracks are identified and treated before applying the waterproofing coating.

• Hairline and non-moving cracks are cleaned and filled using a compatible polymer-modified cementitious repair compound.

• Wider cracks and damaged concrete are opened up and repaired using an appropriate repair mortar.

• Structural or active movement cracks require separate engineering assessment and suitable flexible joint treatment.

• Honeycombs and surface voids are repaired using appropriate repair mortar.

Special attention is given to construction joints and areas where water penetration is already visible.

• STEP 04 – Treatment of slab and parapet wall junctions

• The junction between the horizontal terrace slab and vertical parapet wall is one of the critical locations for water seepage.

• A suitable cement-sand polymer-modified mortar is used to create a rounded coving (Vata) at the junction.

• The coving provides a smooth transition between the horizontal and vertical surfaces, avoiding sharp corners where the waterproofing coating could become thin or vulnerable.

• The treatment is extended approximately 300 mm up the parapet wall, subject to site conditions and system specifications.

• STEP 05 – Preparation of drainage and slope

• The terrace must have adequate slope towards the rainwater outlets.

• Low-lying areas and water-retaining pockets are corrected using suitable repair or slope-correction mortar.

• Drain outlets are cleaned and their surrounding surfaces repaired.

• Water should not remain stagnant on the finished terrace.

• STEP 06 – Application of first cementitious waterproofing coat

• The prepared RCC surface is brought to the moisture condition specified by the waterproofing material manufacturer. For many cementitious systems, this means a saturated surface-dry substrate without standing water.

• The two-component polymer-modified cementitious waterproofing material is mixed according to the manufacturer's prescribed liquid-to-powder ratio.

• The material is mixed until a uniform, lump-free consistency is obtained.

• The first coat is applied uniformly using a suitable brush, roller or trowel, ensuring complete coverage of the concrete surface.

• Particular attention is given to corners, repaired cracks, drain outlets and parapet junctions.

Application guidelines:

• Lay the reinforcement without wrinkles or air pockets.

• Maintain continuous coverage over the designated terrace area.

• Overlap adjoining sheets by approximately 50–100 mm, or as specified by the reinforcement manufacturer.

• Ensure proper embedding at corners and junctions.

• Provide suitable reinforcement detailing around drain outlets and pipe penetrations.

• Ensure the reinforcement is fully embedded and does not remain exposed.

Important: Only one continuous layer of fibreglass reinforcement is used in this system. The reinforcement is not intended to remain exposed.

STEP 08 – Application of second cementitious waterproofing coat

After the first coat has reached the appropriate condition specified by the product manufacturer, the second coat of polymer-modified cementitious waterproofing material is applied.

This coat completely covers the fibreglass reinforcement.

The application is carried out uniformly to achieve the specified coating thickness and to ensure that no fibres remain exposed.

The second coat also helps create a continuous waterproofing layer across the entire treated surface.

STEP 09 – Final inspection and curing

After completion of the coating application, the treated terrace is protected from:

• Direct rain during the initial curing period.

• Premature foot traffic.

• Mechanical damage.

• Excessive heat and rapid drying.

• Contamination by dust and debris.

Curing and protection are carried out strictly according to the cementitious waterproofing manufacturer's technical instructions.

The water level is marked and monitored for approximately 24–72 hours, subject to site conditions and project specifications.

The underside of the slab and adjoining walls are inspected for signs of moisture or leakage.

Any identified defects must be rectified and retested before handover.

Key Benefits of Cementitious Waterproofing

• Crack-control reinforcement: Fibreglass helps distribute tensile stresses within the coating.

• Continuous protection: A properly embedded reinforcement layer helps maintain coating continuity.

• Improved coating integrity: Reinforcement helps reduce localised cracking in the waterproofing layer.

• Concrete compatibility: Cementitious materials can bond effectively with properly prepared concrete substrates.

• Seamless application: The coating is applied as a continuous liquid/paste system rather than using sheet joints across the entire terrace.

• Versatile application: Suitable for different terrace configurations, subject to substrate condition and product compatibility.

• Repairability: Localised defects can be treated using compatible repair and waterproofing materials.