Beat the Heat! Key Construction Tips for Summer High Temperatures in Waterproofing Materials

Summer Construction Precautions for Waterproofing Materials

Currently, many regions across the country are experiencing abnormal high temperatures, significantly affecting waterproofing sub-projects. After installing non-exposed waterproof layers, timely protective measures or construction protection layers must be applied. High temperatures cause excessive thermal expansion in the base layer, leading to trapped air and vapor pressure beneath the tightly sealed waterproof membrane. This may result in blistering, delamination at joints or edges, and even surface peeling. Under intense sunlight and heat, non-exposed waterproof membranes are prone to shrinkage and cracking—especially self-adhesive membranes, which are more severely affected.To prevent the above issues, the following recommendations are provided:

Edge Shrinkage Phenomenon

• Root Cause Analysis

Modified asphalt waterproof membranes experience a rapid increase in surface temperature under high heat. If not fully adhered, moisture vapor generated from the heated base cannot escape, easily causing voids within the membrane. This leads to tensile stress on the membrane, resulting in edge shrinkage (especially noticeable at short edges) when adhesion is weak or vapor accumulates excessively.

• Recommended Measures

① Pre-release membrane stress: Unroll and lay the asphalt membrane flat 1–2 hours before installation.

② Fully adhere during installation to ensure joint openings remain accessible.

③ Complete the protective layer or proceed with the next construction step as soon as possible after installation to minimize adverse effects caused by high temperatures.

Surface Aging of Polyethylene Tape

• Root Cause Analysis

Non-exposed waterproof materials, if not promptly protected or followed by the next construction phase after installation, are exposed to direct sunlight, rain, and other environmental factors. This leads to cracking, aging, and weathering phenomena.

• Recommended Measures

① Immediately inspect and protect or proceed with the next construction phase after non-exposed waterproofing material installation.

② Preferably schedule work during cooler periods in summer.

③ Store materials according to specifications—avoid direct exposure to sunlight.

Self-Adhesive Membranes Are Less Prone to Cracking

• Root Cause Analysis

High summer temperatures cause self-adhesive membranes to absorb heat, softening the modified asphalt layer and increasing surface tackiness. When the adhesive strength exceeds the separation resistance of the insulation layer, it can lead to difficulties in construction efficiency. Additionally, these membranes are more susceptible to damage during transport and handling; damaged membranes or compromised insulation layers after storage can also cause adhesion failure.

• Recommended Measures

① Store materials properly—avoid direct sunlight—and minimize work during peak heat hours.

② Use cold water soaking during high-temperature installation to effectively reduce the adhesion force between the insulation layer and asphalt.

③ Handle and roll the membrane gently to avoid deformation or physical damage.

Membrane Blisters / Blistering, Pinholes

• Root Cause Analysis

High temperatures generate significant thermal expansion in the base layer. After the waterproof membrane is bonded to the structural layer, the tightly sealed membrane traps heat and vapor. This causes blistering (particularly when using pre-adhesive, lap, strip, or spot adhesion methods). High base temperature leads to pinholes and gas pockets.

• Recommended Measures

① Avoid high-temperature work whenever possible; complete the next construction phase as quickly as possible after installation. Do not leave the membrane exposed for long periods (e.g., if blisters appear, vent them first, then reinforce sealing).

② For cold-membrane application in summer, prefer lower base temperatures for optimal results.