Standards
ASTM C1315 Explained
ASTM C1315 is the spec for liquid compounds that cure and seal concrete. Type I is clear and Type II is white; Classes A, B and C rate yellowing. Manufacturer summaries put the water loss limit at 0.40 kg/m² in 72 hours at 300 ft²/gal, with at least 25% solids. The current revision is C1315-25.
ASTM C1315 is the spec you cite when the product has to do more than hold water in. It covers compounds that cure fresh concrete and leave a sealing film behind. This page follows the C1315-25 revision. Where the free ASTM abstract stops, the numbers come from manufacturer summaries, each linked.
What does ASTM C1315 cover?
C1315 covers liquid membrane-forming compounds used to cure and seal fresh concrete, and to seal hardened concrete. The ASTM C1315-25 abstract says these compounds must also show alkali resistance, acid resistance, adhesion-promoting qualities and resistance to UV light.
Like C309, it is a performance spec. It sets what the film must do, not what it is made of, so both water-based and solvent-based acrylics can qualify. ASTM lists C1315-25 as active, last updated October 8, 2025. Earlier revisions include C1315-19, C1315-11 and C1315-08.
What are the ASTM C1315 types and classes?
C1315 sorts products by color (type) and by how much they yellow (class). The class letters mean something different from the C309 classes, which is the most common mix-up on submittals. The definitions below follow Dayton Superior’s Guide to Cure and Seals.
| Designation | What it means | Typical use |
|---|---|---|
| Type I | Clear | Colored, stamped and exposed slabs, interior floors |
| Type II | White pigmented | Exterior work where you want reflectance |
| Class A | Non-yellowing | Colored and decorative concrete |
| Class B | May have moderate yellowing | Plain gray slabs where some ambering is acceptable |
| Class C | May undergo severe darkening; no yellowing requirement | Work where color change does not matter |
Some blogs describe Class A as “ready to use” and Class B as “dilute on site.” That does not match the ASTM abstract, which classifies these products as non-yellowing, moderately yellowing, or yellowing and darkening without limit.
What limits does a C1315 compound have to meet?
A C1315 product has to hold more water than a C309 product, at a lighter application rate, with a thicker solids load. On top of that it has to pass resistance and adhesion tests. The table pulls the numbers from the manufacturer summaries; the property list is from the ASTM abstract.
| Requirement | Limit | Source |
|---|---|---|
| Water loss (ASTM C156) | Not more than 0.40 kg/m² in 72 hours | Dayton cure and seal guide |
| Test application rate | 300 ft²/gal (7.4 m²/L) for Type I | Dayton; ChemMasters for metric |
| Solids content | At least 25% | Dayton; Euclid Chemical |
| Type II test rate and reflectance | 200 ft²/gal, 65% reflectance | ChemMasters summary |
| Added properties | UV, acid and alkali resistance; adhesion | ASTM abstract |
| Yellowing | Class A non-yellowing, B moderate, C unrestricted | ASTM abstract |
ChemMasters’ C1315 summary gives the Class A and B yellowing limits as Gardner color standards No. 1 and No. 3. Euclid Chemical puts a 25% solids product at about 1.3 mils dry film at 300 ft²/gal in one coat.
How is ASTM C1315 different from C309?
C1315 is the tougher spec. It asks for better water retention at a thinner application, a minimum solids content, and tests that ASTM C309 does not have. The ASTM abstract’s own Note 1 sends you to C309 for compounds specified mainly on water retention.
| Item | C309 | C1315 |
|---|---|---|
| Purpose | Curing only | Curing and sealing |
| Water loss in 72 hours | 0.55 kg/m² | 0.40 kg/m² |
| Test application rate | 200 ft²/gal (4.9 m²/L) | 300 ft²/gal (7.4 m²/L), Type I |
| Minimum solids | None | 25% |
| Class letters mean | Solids type (A any, B all resin) | Yellowing (A, B, C) |
| UV, acid, alkali tests | No | Yes |
| Adhesive pull-off test | No | Yes, one ceramic tile adhesive |
The C309 figures come from Dayton Superior’s Guide to Curing. Many products are listed under both specs. That is normal: a film that passes the tighter C1315 water test will usually pass the C309 test too.
When should you specify C1315 Type I Class A?
Specify Type I Class A when the slab is colored, stamped or exposed and the finish has to look right for a few years. Dayton’s guide says ACI 308 recommends a C1315 Type I Class A cure and seal for colored concrete floors and slabs.
The same guide adds that even non-yellowing compounds discolor over time. For plain gray paving or a slab that gets flooring, C1315 is usually more film than you need. The trade-offs between a cure and seal and a plain curing compound are covered on that page.
Euclid Chemical notes solvent-based cure and seals are not recommended indoors because of the odor while they apply and dry. On interior floors, ask for a water-based C1315 product.
How do you read a C1315 label or submittal?
Read four things on the data sheet: the standard, the type, the class and the application rate the product was tested at. Check the class letter against the right standard, because a “Class A” under C309 means something else.
A real example: the Masco Cure and Seal 1315 data sheet lists ASTM C-1315 Type 1, Class A and ASTM C-309 Type 1, Class B. It is a solvent-based styrene acrylic, applied at 300 square feet per gallon on fresh concrete.
Check each submittal for:
- C1315 named, with a revision year if your spec gives one
- Type I (clear) or Type II (white) matching the spec
- The yellowing class, usually Class A on colored work
- An application rate no lighter than the 300 ft²/gal test rate
- Water-based or solvent-based, and whether that suits an interior space
- What the maker says about flooring adhesives, coatings and toppings
For a full spec section, use the specifier checklist for curing compounds.
If flooring is going over a C1315 cure and seal
Test before you install. The C1315 pull-off test uses a single ceramic tile adhesive, and The Construction Specifier points out that you cannot extrapolate other adhesives from a test of only one. Dayton states plainly that meeting C1315 does not assure compatibility with all mastics and adhesives.
What to do on the slab:
- Get the flooring maker’s position in writing. Many want the slab free of any film. Masco’s own sheet says to consult the floor covering maker and run a test section.
- Bond test with the job adhesive. Use the actual adhesive and flooring on a small area and check the bond before the full install.
- Remove the film if the test fails. A sealing film is built to last, so do not wait for it to wear off. See curing compound and flooring for removal and moisture testing.
- Plan ahead next time. If flooring or coatings follow, a C1315 product was likely the wrong pick for that area.
Frequently asked questions
What is the current revision of ASTM C1315?
The ASTM store lists C1315-25 as the active revision, last updated October 8, 2025. Earlier revisions include C1315-19, C1315-11 and C1315-08. If your spec names an older year, ask whether the newer revision is acceptable before you approve a submittal.
What is the difference between ASTM C309 and C1315?
C309 covers curing compounds rated mainly on water retention. C1315 covers compounds that cure and seal, with a tighter water loss limit (0.40 vs 0.55 kg/m² in 72 hours), a 25% minimum solids content, and added tests for UV, acid and alkali resistance and adhesive bond.
What does Type I Class A mean in ASTM C1315?
Type I is clear or translucent. Class A is the non-yellowing class. Dayton Superior's guide says ACI 308 recommends a C1315 Type I Class A cure and seal for colored concrete floors and slabs, and notes that even non-yellowing compounds discolor over time.
Does a C1315 cure and seal guarantee flooring adhesive will bond?
No. The C1315 pull-off test uses one ceramic tile adhesive, and Dayton Superior states that meeting C1315 does not assure compatibility with all mastics and adhesives. Test the actual adhesive on the actual slab before the flooring goes down.
Is ASTM C1315 only for water-based acrylics?
No. The standard is a performance spec and does not limit chemistry. Solvent-based products also claim it; Masco Cure and Seal 1315, for example, is a solvent-based styrene acrylic listed as C1315 Type 1, Class A.