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Sika Thoroseal 581 White 50lb Bag
Thoroseal 581 is a Portland cement-based coating for concrete and masonry that resists both air infiltration and positive as well as negative hydrostatic pressure. Creates a low maintenance and highly durable waterproof barrier.
- Breathable
- Protects from dampness and moisture damage
- Compatible with coatings
$45.85
SKU
21449
Sika Thoroseal 581 White Waterproof Coating – 50 lb Bag
Sika Thoroseal 581 is a Portland cement-based coating for concrete and masonry that resists air infiltration and both positive and negative hydrostatic pressure. When polymer-modified with Sika Thoroseal Acryl 60, it is used to create a durable waterproof barrier for interior or exterior applications above or below grade where breathability and moisture resistance are required.
Key Features
- Resists positive and negative hydrostatic pressure for below-grade and water-side applications.
- Air barrier performance helps reduce air infiltration through concrete and masonry substrates.
- Breathable coating allows internal moisture vapor to escape without damaging the finish.
- Compatible with many architectural coatings and textured finishes after curing.
- Certified to NSF/ANSI Standard 61 for potable water contact when used as directed.
- White finish for bright, clean appearance and improved reflectance in utility spaces.
Applications
- Basement and retaining walls (interior and exterior conditions as applicable).
- Foundations and below-grade concrete or masonry surfaces.
- Water cisterns and water treatment construction where hydrostatic resistance is needed.
- Bridges and tunnels on non-traffic-bearing surfaces.
- Concrete masonry units, brick, porous stone, cast-in-place concrete, and precast concrete.
Technical Specifications:
| Property | Value |
|---|---|
| Chemical Base | Contains cement, graded sand, and proprietary additives |
| Packaging | 50 lb (22.7 kg) polyethylene-lined bag |
| Appearance / Color | White |
| Shelf Life | 1 year when properly stored |
| Storage Conditions | Store unopened in a clean, dry place protected from rain, dew, and humidity. Do not stack bags more than two pallets high. |
| Density (cured) | 129 lbs/ft3 (2,080 kg/m3) when cured (Lab Method) |
| Coverage (base coat) | 225 ft2 per 50 lb bag at 1/16 in (1.6 mm) dry-film thickness |
| Coverage (topcoat) | 450 ft2 per 50 lb bag at 1/32 in (0.8 mm) dry-film thickness |
| Set Time | 10 minutes at 70 F (21 C), 50% RH (Lab Method) |
| Final Set Time | 90 minutes at 70 F (21 C), 50% RH (Lab Method) |
| Compressive Strength | 6,030 psi (42 MPa) at 28 days (ASTM C109) |
| Tensile Adhesion Strength | 418 psi (2.9 MPa) (Test by tensile bond) |
| Water Penetration (positive pressure) | 752 hours at 200 psi (1.4 MPa), no leakage, no softening (CRD C48, modified) |
| Water Penetration (negative pressure) | 664 hours at 200 psi (1.4 MPa), limited dampness (CRD C48, modified) |
| Permeability to Water Vapor | 12 perms (ASTM E96 water-vapor transmission) |
| Freeze-Thaw Stability | No change after 200 cycles (ASTM C666 Procedure B) |
| Potable Water Contact | Certified to NSF/ANSI Standard 61 |
Frequently Asked Questions
Can Sika Thoroseal 581 be used for negative-side waterproofing?
Yes. It is designed to resist both positive and negative hydrostatic pressure when used as directed.
Do I need to use Acryl 60 with this product?
Yes. The product must be modified with Sika Thoroseal Acryl 60 to achieve the properties listed in the technical data.
What coverage should I expect from a 50 lb bag?
A 50 lb bag covers about 225 ft2 as a base coat at 1/16 in dry-film thickness and about 450 ft2 as a topcoat at 1/32 in dry-film thickness. Coverage varies with surface texture and porosity.
Where is this coating typically used?
Common uses include basement and retaining walls, foundations, water cisterns, and concrete or masonry surfaces above or below grade where water resistance and breathability are needed.
How should the material be stored on site?
Keep unopened bags in a clean, dry place protected from rain, dew, and humidity, and do not stack bags more than two pallets high.
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