Curing compound
Dissipating Curing Compound Explained
A dissipating curing compound is a resin film that breaks down under sunlight and traffic, usually starting in about 4 to 8 weeks. Wax compounds do not dissipate. Indoors and in shade, breakdown is slow and hard to predict, so plan to test the slab and clean it before any flooring goes down.
If flooring, coatings or a topping go on the slab later, the cure you spray on day one decides how much prep you face weeks from now. A dissipating compound is the usual answer, but “dissipating” describes what the film does in sun and traffic, not a promise that the slab will be clean on move-in day.
What is a dissipating curing compound?
A dissipating curing compound is a resin based membrane, with no wax, that oxidizes and breaks down under UV light and traffic. Nox-Crete describes its Res-Cure DH 100 as a dissipating hydrocarbon resin without waxes, paraffins, gums or oils, rated ASTM C309 Type 1, Class A and B.
The opposite is a non dissipating compound. Wax based cures and acrylic cure and seals stay on the slab. The Dayton Superior Guide to Curing says wax membranes “do not dissipate and will be present until removed.”
How long does dissipating curing compound take to break down?
Most data sheets say breakdown starts somewhere between about 4 and 8 weeks with sun and traffic, and some give a wider range. Read these as starting points under good exposure, not finish dates. W.R. Meadows says on its dissipation FAQ that full dissipation is “extremely difficult to predict.”
| Product | What the maker says | Conditions stated |
|---|---|---|
| W.R. Meadows CC-309-1WS | Begins to break down after about 4 weeks | UV exposure |
| SpecChem SpecRez | Breakdown starts in 4 to 6 weeks | Normal conditions |
| Tenon Dissipating Cure 1315 WB | Breaks down in 5 to 8 weeks | UV and sunlight |
| Nox-Crete Res-Cure DH 100 | Typically dissipates within 30 to 90 days | Not stated |
| Dayton Clear Cure J7WB | Begins to dissipate in 7 to 10 days | Without UV |
| Dayton J11W | Begins to dissipate in 60 to 90 days | Product table (the guide’s text says 30 to 60) |
Sources: CC-309-1WS data sheet, SpecRez product page, Dissipating Cure 1315 WB data sheet, and the Nox-Crete and Dayton documents linked above.
What slows dissipation down?
Anything that keeps sun and traffic off the film, or puts more film down, slows it. W.R. Meadows lists porosity, application rate, UV light, temperature, humidity and traffic as the variables. Euclid’s Kurez DR VOX data sheet adds that the film must stay uncovered and unprotected to dissipate.
- No sunlight. Interior slabs, slabs under a roof deck and shaded areas get little UV.
- Heavy or uneven spraying. Euclid warns heavy application slows dissipation and makes removal harder.
- Covering the slab. Plastic, hardboard or stored material blocks UV and traffic.
- Cold and damp weather. Temperature and humidity are on the W.R. Meadows list.
Spray at the maker’s rate and no heavier. Euclid lists 300 ft²/gal (7.4 m²/L) on textured concrete and 400 ft²/gal (9.8 m²/L) on smooth, and says not to apply a thicker film. Check your order with the curing compound coverage calculator.
Is dissipating curing compound safe under flooring?
Only once the film is gone or cleaned off. “Dissipating” does not mean the flooring maker will accept it. An AECOM Hunt quality bulletin says almost all floor leveling and flooring manufacturers require the concrete to be free of curing compounds.
ACI 302.1R, as quoted by Floor Expert, says curing compounds should be avoided on surfaces that will later get resilient flooring. The same page says any compatibility letter must come from the compound’s manufacturer, not the flooring supplier. For the full picture on adhesives and bond, see curing compound and flooring.
How do you use a dissipating compound when flooring goes on later?
Treat the compound as something you will verify and probably clean off, not something that will vanish. AECOM’s bulletin goes further and recommends 7 days of wet curing under plastic or burlap when flooring is planned. If you do spray, work the steps below.
- Pick a resin product with no wax, listed as Class B or as dissipating. The curing compound chooser can narrow it down.
- Get the flooring and adhesive maker’s slab requirements before the pour.
- Ask the compound maker for a compatibility letter if you plan to leave any residue.
- Spray one even coat at the data sheet rate, no puddles.
- Leave the slab uncovered and in sun where you can.
- Before flooring, water drop test the slab across sunny, shaded and heavy areas. See how to test for curing compound.
- Clean any area that fails, then run a bond test. Floor Expert says if the bond fails after 72 hours, the compound must be removed.
If the curing compound has not dissipated
On interior slabs this is common, so it is not a sign the product was bad. Dayton’s guide describes a dissipating cure as mottled, yellow and dusty, and says that if water is not readily absorbed, more cleaning may be needed.
Concrete Decor describes a slab where the roof was already on and the compound went on heavy, so it never broke down. The fix there was to strip it chemically or wet grind. Retest with water drops after cleaning, then bond test before the full install.
Frequently asked questions
What is a self dissipating water borne curing compound?
It is a water-based resin curing compound made to break down on its own under UV light and traffic. Products such as SpecChem SpecRez and W.R. Meadows CC-309-1WS are sold this way. Self dissipating does not mean it disappears indoors on a schedule; it still needs checking before flooring.
How long does curing compound take to dissipate?
Manufacturer data sheets give anything from about 4 weeks to 90 days, with full sun and traffic. W.R. Meadows says it is extremely difficult to predict, because porosity, application rate, UV, temperature, humidity and traffic all change it.
What is a non dissipating curing compound?
One whose film stays until it is worn off or removed. Wax based compounds and acrylic cure and seals are non dissipating. Dayton Superior's guide says wax membranes will be present until removed.
Can I install flooring over a dissipating curing compound?
Only once it is gone or removed and a bond test passes. Most flooring and leveler makers require the slab to be free of curing compound. Get the flooring maker's requirements in writing before the pour if you can.
How do I know if the curing compound is gone?
Put drops of water on the slab. If they soak in readily, the film is likely gone in that spot. If they bead or sit, more cleaning is needed. Test several spots, especially shaded areas and places the crew sprayed heavy.