Description
Overview
Sika Thoroseal 581, formerly MasterSeal 581, is a Portland-cement-based waterproofing and air-barrier coating for concrete and masonry. Mixed with Sika Thoroseal Acryl 60 as specified, it resists positive and negative hydrostatic pressure while allowing moisture vapor to escape.
Features
- Helps protect building interiors from dampness and moisture penetration.
- Reduces air infiltration without creating an impermeable vapor barrier.
- Conceals minor concrete surface defects and accepts a range of compatible architectural coatings and textured finishes.
- Certified to NSF/ANSI Standard 61 for potable-water contact, subject to the application and curing requirements.
What's Included
- 1 × 50 lb bag of Thoroseal 581 in the selected color
- Acryl 60 mixing additive is a separate product required by the application instructions.
Specifications
- Package: 50 lb bag
- Colors: Gray or White
- Base-coat coverage: Up to 225 sq. ft. per 50 lb at 1/16 in. dry-film thickness
- Topcoat coverage: Up to 450 sq. ft. per 50 lb at 1/32 in. dry-film thickness
- Coverage variation: Depends on substrate texture and porosity
- Laboratory set times: Initial: approximately 10 minutes; final: approximately 90 minutes at 70°F and 50% RH
- Mixed pot life: Approximately 60–90 minutes at 70°F; shorter in hot, dry conditions
- Shelf life: 1 year when properly stored unopened in a clean, dry location
Color Options
- Gray
- White
Downloads
Applications
Use on cast-in-place or precast concrete, concrete block, brick and porous stone. Suitable applications include interior or exterior foundations, basements, retaining walls, concrete or masonry rough-opening flashing, water cisterns, and non-traffic-bearing bridge or tunnel surfaces. Horizontal use is limited to light pedestrian service.
Selection and Use
- Acryl 60 modification is required to achieve the published properties. The specified maximum dilution is 1 part Acryl 60 to 3 parts water, with approximately 6 quarts of total mixing liquid per 50 lb of powder; follow the complete mixing and application instructions.
- Do not coat active water leaks or moving cracks. Prepare the substrate and repair static defects before coating.
- Follow the data sheet’s application-specific details for below-grade work, stucco and water tanks; these are not interchangeable assemblies.
- Allow 7–10 days of curing before immersion. Check water quality before specifying: the coating is not intended for continuous acid- or sulfate-containing water, and very soft water can adversely affect it.
- The listed coating set times are laboratory measurements, not permission for immediate immersion or full service.
