Division 02 — Construction / Joint Sealants

Joint Sealants

Construction joint sealants are flexible, adhesive compounds applied to movement joints, construction joints, and perimeter gaps in concrete, masonry, and facade assemblies to seal against water, air, and dust ingress while accommodating the cyclic relative movement between adjacent structural elements caused by thermal expansion, loading, and settlement.

CFC Egypt's joint sealant range addresses the full spectrum of construction sealing requirements. EGYFLEX PU polyurethane sealant is the standard workhorse for floor joints, expansion joints in concrete structures, and general building sealing — offering high elongation capacity, strong adhesion to concrete and masonry, and trafficability after cure. EGYROD closed-cell polyethylene backing rods provide the correct depth control and bond-breaker function that every properly designed sealant joint requires. EGYCELL SHEET foam provides compression-controlled joint backing for wide or irregular joints. All products are manufactured at our Sadat City, Egypt facility.

01

What It Covers

The joint sealant category covers three interconnected product types that together deliver a complete, correctly designed joint sealing system.

01

Polyurethane Sealants

EGYFLEX PU is a one- or two-component polyurethane elastomeric sealant for movement joints in concrete floors, facades, expansion joints, window perimeters, and general construction sealing. It offers high elongation capacity (typically 25% or greater joint movement accommodation), strong adhesion to concrete, masonry, metals, and most construction substrates without priming on prepared surfaces, and resistance to foot and light vehicular traffic once cured. Paintable after cure; low odour formulation available.

02

Backing Rods

EGYROD closed-cell polyethylene foam rods are inserted into the joint before sealant application to control the depth-to-width ratio of the sealant bead and prevent bonding at the base of the joint. Three-sided adhesion is the most common cause of sealant joint failure — EGYROD eliminates this risk by acting as both a bond breaker and a depth gauge. Available in a range of diameters to suit joint widths from 8 mm to 50 mm; selected oversize relative to joint width for positive compression.

03

Compression Foam Backing

EGYCELL SHEET is a closed-cell polyethylene foam sheet used as a compressible backing and bond breaker for wide joints, irregular joint profiles, and transition details where cylindrical rods cannot be used. It is also used as pre-compressed expansion joint filler in concrete elements where slab-to-slab gaps must be maintained through the pour. Cut easily on site to the required dimensions; compatible with polyurethane and polysulphide sealants.

02

Where They're Used

Construction joint sealants are specified wherever water exclusion, air tightness, or movement accommodation is required at a gap between structural or facade elements. The following applications represent the most critical sealing requirements in modern construction.

Building Facades & Curtain Walls

External facade joints between precast concrete panels, aluminium curtain wall sections, and cladding elements must accommodate thermal movement — in Egypt's climate, a one-metre aluminium section can move up to 2 mm through daily temperature cycles — while remaining permanently watertight and weather-resistant. High-movement sealants with proven UV stability and adhesion to concrete, masonry, and coated aluminium are specified for all primary weathering joints in facade assemblies.

Concrete Floor Expansion Joints

Industrial and commercial concrete floor slabs incorporate expansion and contraction joints at regular intervals to manage the thermal and drying shrinkage movements of the slab. These joints must be sealed to prevent dust, liquids, and debris from entering the joint and lifting slab edges under forklift impacts. Polyurethane sealants provide the right combination of flexibility, trafficability, and adhesion to concrete for floor joint sealing in warehouses, factories, retail, and car parks.

Water-Retaining Structures

Reservoirs, tanks, treatment plant basins, swimming pools, and water channels require sealants that maintain impermeability under continuous water pressure and resist biological growth and water treatment chemicals. Joint sealing in water-retaining structures uses high-performance elastomeric sealants with permanent flexibility and excellent adhesion; proper backing rod installation ensures that the sealant geometry allows free movement without cohesive failure at the joint centre.

Window & Door Perimeter Sealing

The perimeter joint between a window or door frame and the surrounding concrete or masonry must be continuously waterproof and airtight over the building's lifetime, accommodating the differential movement between the lightweight frame and the heavy structure. Polyurethane sealants provide the necessary adhesion to both aluminium and concrete without priming in most cases, and remain permanently flexible, preventing water penetration at one of the most vulnerable weathering interfaces in any building envelope.

Infrastructure & Civil Engineering Joints

Bridge deck expansion joints, road pavement joints, airport apron joints, and tunnel lining joints represent the most demanding sealing applications in terms of movement, traffic loading, and chemical exposure. These joints require sealants with high Shore hardness for trafficability, wide temperature performance, and resistance to fuel, de-icing salts, and UV exposure. Correct joint geometry design — width, depth, backing rod size — is as critical as sealant product selection for long-term infrastructure joint performance.

03

CFC Joint Sealant Products

Polyurethane sealants, backing rods, and foam backing sheets for movement joints and construction joints — all manufactured in Sadat City, Egypt.

EGYCELL SHEET

Замедлитель схватывания бетона и суперпластификатор (ASTM C-494 - тип A, D и G)

EGYFLEX PU

Замедлитель схватывания бетона и суперпластификатор (ASTM C-494 - тип A, D и G)

EGYROD

Замедлитель схватывания бетона и суперпластификатор (ASTM C-494 - тип A, D и G)

04

Frequently Asked Questions

Technical and commercial questions on construction joint sealants answered plainly. For a specific application or joint design recommendation, contact our technical team.

A joint sealant is a flexible, adhesive compound applied to the gap between two construction elements — concrete panels, facade units, floor slabs, or structural members — to seal the joint against water ingress, air infiltration, dust, and noise while accommodating the relative movement that occurs due to thermal expansion and contraction, structural loading, and settlement. Joint sealants are required wherever two adjacent elements cannot be rigidly bonded and must remain watertight and weathertight despite the cyclic movement of the joint over the building's service life.

A movement joint sealant must accommodate significant, repeated cyclic movement — typically ±12.5% to ±25% of the joint width — and is selected for high elongation capacity and fatigue resistance. Movement joints occur at expansion joints in facades and floors, and at perimeter joints between floor slabs and walls. A construction joint sealant seals the gap at a planned construction break in a concrete pour where movement is limited; these joints require good adhesion and waterproofing performance but lower elongation capacity. Polyurethane sealants are most commonly used for both joint types in Egyptian construction.

Polyurethane sealants offer excellent adhesion to concrete, masonry, and most construction substrates, good mechanical strength, and resistance to foot and vehicular traffic — making them the standard choice for floor joints, expansion joints, and general construction sealing. They can be painted once cured. Polysulphide sealants provide outstanding resistance to water, fuel, and chemicals, with very long service life in permanently submerged or chemically exposed conditions. Silicone sealants offer the widest temperature range, best UV stability, and excellent weathering resistance, making them the preferred choice for glazing, curtain wall, and exposed facade joints.

The joint width should be at least four times the expected maximum movement, so that the sealant is never stressed beyond its rated elongation capacity. For a movement of 5 mm, the joint should be at least 20 mm wide. The depth of sealant is typically equal to half the width for joints up to 20 mm wide, and fixed at 10–12 mm for wider joints, controlled by a correctly sized backing rod (EGYROD) that supports the sealant and ensures the correct depth-to-width ratio for a compliant two-sided adhesion geometry.

A backing rod is a compressible closed-cell polyethylene foam rod (EGYROD) inserted into a joint before sealant application to control sealant depth and prevent three-sided adhesion. Three-sided adhesion — where the sealant bonds to both joint faces and the joint bottom — prevents the sealant from elongating freely under movement, leading to cohesive failure. The backing rod acts as a bond breaker at the joint base and positions the sealant at the correct depth-to-width ratio for optimum performance. Correct backing rod selection and installation is as important as the sealant product itself for long-term joint durability.

Поговорите с нами

Ready to seal your construction joints correctly?

Tell us the joint type, substrate materials, expected movement, and exposure conditions. Our technical team will recommend the right sealant system — including sealant product, primer requirements, and backing rod sizing — for a long-lasting, maintenance-free seal.