How do sealants and joints fail over time?

Sealants and expansion joints are essential for protecting commercial building envelopes by preventing water intrusion and accommodating structural movement. Over time, these materials naturally degrade due to several factors specific to the New England climate, building materials, and use cycle.

The most common causes of sealant and joint failure include:

• Weathering and UV Exposure: Prolonged exposure to sunlight, rain, and wind causes sealant compounds to lose their flexibility and adhesion. UV breakdown can result in surface cracking, chalking, or brittleness.

• Thermal Movement: Buildings in New England experience significant temperature swings and freeze-thaw cycles. As materials expand and contract, sealants must flex accordingly. Over time, repeated thermal cycling can lead to loss of adhesion (cohesive or adhesive failure), tearing, or separation from the substrate.

• Moisture and Water Intrusion: Persistent moisture, especially from wind-driven rain or snow and ice accumulation, can infiltrate joints or deteriorate poorly bonded sealant. Water ingress may accelerate degradation and result in hidden substrate damage.

• Chemical Exposure: In parking garages or plaza decks, de-icing salts and environmental pollutants may attack certain sealants, causing premature breakdown or staining.

• Aging and Curing: All sealants have a service life. As they age, elasticity, adhesion, and overall performance decline. Old or improperly cured sealants may harden, shrink, or lose key properties sooner than specified.

• Improper Specification or Installation: Using the wrong sealant for the substrate, improper joint design, inadequate surface preparation, or incorrect application techniques can all lead to early failure.

Visible signs of failure include cracking, splitting, separation from the building material, discoloration, or loss of flexibility. In severe cases, failed sealants or joints may allow water entry, which can damage underlying masonry, concrete, or structural components, leading to more costly repairs down the line.

Regular inspection of building joints, especially at high-movement transitions and critical penetrations, is essential for commercial property owners and managers. Preventative maintenance planning, using high-quality, manufacturer-approved materials, and professional installation are key for long-term waterproofing performance and protecting building assets in New England’s challenging climate.