Frequently Asked Questions

Why is joint sealing with Colpor 200PF important and what happens if floor joints are left unsealed?

Concrete floor joints must be sealed to prevent two main types of damage. First, small stones, grit, and debris from forklift tyres and foot traffic fall into open joints and compact at the base of the joint. When the concrete slab expands in warm weather, the joint must close — but incompressible debris prevents this, and the expanding slab transfers very high compressive load to the joint edges. The concrete at the joint edges then fails in tension (the top arris of the joint edge cracks and spalls away), creating a wheel path obstruction that damages forklift tyres, damages goods carried on forklifts, and rapidly widens into a major floor defect. Second, water entering the open joint — from floor washing, rain (for external slabs), or process water — attacks the sub-base and can cause differential settlement of the slab panels, producing differential slab edges at joints that are even more damaging to forklift operations. Sealing joints immediately after the concrete has been cut and has achieved initial strength (typically 28 days) prevents both of these damage mechanisms.

What is the correct joint preparation procedure before applying Colpor 200PF?

Joint preparation is critical for achieving the required bond between Colpor 200PF and the concrete joint faces. The saw-cut joint must be cleaned of all concrete dust, debris, curing compound, and contamination by blowing out with compressed air and vacuuming — any residual cutting dust will prevent adhesion of the sealant to the joint faces. The joint width and depth must be within the specification range (typically the joint is routed to a width of 8 to 20 mm if the saw cut is narrower, using a concrete router to produce a clean rectangular joint profile). A foam backing rod of appropriate diameter is inserted to the correct depth to control the sealant depth-to-width ratio (typically 1:1 to 1:2). The joint faces must be dry (or surface-dry in a damp floor condition). A polyurethane primer is applied to the concrete joint faces and allowed to cure to the specified tack before Colpor 200PF is poured in. The primer significantly improves adhesion of the sealant to the concrete and must not be omitted.

How long after floor completion should Colpor 200PF be used to seal the joints and how long does it take to cure before traffic?

The timing of joint sealing after concrete slab completion is important. The concrete slab must have achieved sufficient drying shrinkage and carbonation-related contraction before the joints are sealed — if sealed too early, the subsequent shrinkage of the concrete will pull the joint open further than the sealant was installed at, potentially overstressing the sealant in tension at its adhesion interface. A minimum of 28 days after concrete placement is typically recommended before sealing floor joints, with some specifications requiring 42 to 60 days for heavy-duty slabs or in humid conditions where drying is slow. After Colpor 200PF is poured into the prepared joints, foot traffic can typically be permitted after 24 hours and light rubber-tyred forklift traffic after 48 to 72 hours depending on the ambient temperature. Heavy steel-wheeled pallet jack traffic should be avoided for 7 days to allow full cure of the sealant.