1. Different adaptability to base layers
Waterproofing membranes: Mostly in the form of sheet-like solids (such as asphalt membranes, polymer membranes), they have higher requirements for the flatness of the base layer. The base layer must be dry, flat, and free of sharp protrusions; otherwise, problems like hollowing or edge warping (especially at membrane joints) are likely to occur.
Suitable for: Large-area, flat base layer scenarios (e.g., roof surfaces, large basement floors).
Waterproofing coatings: Mostly in liquid form (emulsion-type, solvent-based), they form a continuous film after curing through brushing. They can self-level, adapt to irregular base layers (such as internal and external corners, pipe roots, and special-shaped structures), and tightly wrap around detailed parts of the base layer, avoiding "dead corners" that are difficult for membranes to cover.
Suitable for: Scenarios with complex base layers and many edges/corners (e.g., bathrooms, kitchens, balconies, special-shaped sections of tunnels).
2. Different construction conditions and flexibility
Waterproofing membranes: Construction relies on "laying" (adhesive bonding, heat fusion, mechanical fastening, etc.). They are sensitive to the ambient temperature during construction (e.g., asphalt membranes tend to embrittle at low temperatures and flow at high temperatures). While efficient for large-area laying, they are cumbersome to operate in small areas or complex parts (requiring cutting and splicing).
Waterproofing coatings: Construction is mainly based on "brushing/spraying", no cutting is needed, and they have strong adaptability to small areas and special-shaped structures. They can also be constructed on damp base layers (some emulsion-type coatings), offering higher construction flexibility. However, their efficiency is lower than that of membranes for large-area construction (requiring multiple coats for curing).
3. Differences in deformation resistance and durability
Waterproofing membranes: They have high physical strength (excellent tensile and tear resistance) and are suitable for scenarios where the base layer may undergo significant deformation (e.g., roofs affected by temperature changes and structural settlement). However, the joints of membranes are weak points, which may leak if improperly constructed.
Waterproofing coatings: After curing, they form a seamless integral film, with better impermeability. They also have good elasticity (e.g., polyurethane coatings) and can adapt to micro-cracks in the base layer. However, the coating thickness is relatively thin (usually 1-3mm), and they are prone to aging when exposed to sunlight for a long time (requiring a protective layer) and have lower abrasion resistance than membranes.
4. Typical application scenarios
Waterproofing membranes:
Roof waterproofing (especially large-area laying on flat roofs and sloped roofs);
Basement floors and side walls (needing to withstand structural settlement);
Engineering projects with high strength requirements, such as large pools and dams.
Waterproofing coatings:
Bathrooms, kitchens, and balconies (with many pipes and internal/external corners, requiring detailed sealing);
External wall waterproofing (adapting to micro-deformations of walls);
Renovation of old roofs and old buildings (can be directly brushed on the original waterproof layer).
Summary
Waterproofing membranes are suitable for large-area, flat base layers with high requirements for strength and deformation resistance; waterproofing coatings are suitable for small-area, complex base layers needing detailed sealing. In actual projects, "membranes + coatings" are often used in combination (e.g., membranes for main waterproofing and coatings for treating joints and corners) to complement each other's advantages and enhance the waterproofing effect.
