APP Membrane Waterproofing: Where Torch-Applied Systems Succeed or Fail
Torch-applied APP membranes can provide robust sheet waterproofing, but overlaps, laps, detailing, substrate preparation and protection determine continuity.
Water tracks beneath an APP membrane after rain.
Use the site evidence to agree a project-specific method with the responsible engineer, concrete producer, manufacturer or specialist applicator.
Water tracks beneath an APP membrane after rain.
Inspect lap width, torch fusion, fishmouths, substrate adhesion and terminations.
Cold laps, overheating or wrinkles can interrupt sheet continuity.
Remove unsound areas and rebuild laps and details with compatible material.
Follow product-specific overlap and torch method; use fire controls and protect finished work.
Inspect every lap and termination before protection; carry out specified seam or water test.
Do not leave exposed fishmouths under protective screed.
References inform the topic; they do not endorse a specific product for this project.