Inspecting the substrate is paramount in waterproofing membrane construction, directly determining its success or failure. Here's a breakdown of the key points and steps to ensure a flawless process:
Inspection Content and Standards
Smoothness: Use a 2-meter straightedge. The gap between the substrate and the straightedge should not exceed 5mm, and the gap should change smoothly.
Dryness: Use the "plastic film covering method" test. Lay 1㎡ of plastic film flat on the leveling layer and let it stand for 3-4 hours. If there are no watermarks on the covered area or the film, the substrate is dry enough.
Cleanliness: Thoroughly remove dust, oil, laitance, and other debris to ensure a clean substrate surface.
Corner Treatment: Inside and outside corners should be rounded. A radius of at least 50mm (bathrooms, kitchens) or 100mm (roofs, exterior walls) is recommended to prevent stress concentration and cracking of the waterproofing layer.
Firmness: The substrate should be firm, without looseness or hollow areas.
Inspection Methods
Flatness: Check using a 2-meter straightedge and wedge gauge.
Dryness: Test using the "plastic film covering method".
Cleanliness: Visually inspect and confirm by touch.
Inside and outside corners: Measure the radius of the arc with a tape measure.
Firmness: Check for looseness or hollow areas.