We earn a commission if you buy through links on this page, at no cost to you. How we choose products
Buy the epoxy paste kit if your wall is ever damp or you want the lower price. Buy the peel-off kit if the wall is dry, the basement is warm and the wall will stay exposed, so a clean finish matters. The foam that seals the crack is the same in both; only the surface paste that holds the ports differs.
The paste is the surface seal: it glues the injection ports over the crack and keeps the foam inside the wall until it cures. Epoxy paste stays on the wall afterward; peel-off paste is pulled off with the ports.
What is the difference between peel off and epoxy paste?
Epoxy paste is a two-part epoxy that bonds hard to the concrete and stays put. Peel-off paste is a polyurea that holds well enough for injection, then pulls off in a strip.
According to each kit’s product page, the epoxy paste “will cure in the presence of moisture,” while the peel-off paste “will not cure in the presence of moisture and should not be applied to damp or wet surfaces.” That one line decides the choice for many basements.
Both kits use the same polyurethane injection foam and the same steps, which the foam injection guide walks through.
| Epoxy paste | Peel-off paste | |
|---|---|---|
| Material | Two-part epoxy, mixed by hand from jars (10 ft kit) | Polyurea, from cartridges |
| Damp wall | Cures in damp conditions; still apply to a dry surface | Won't cure on a damp or wet surface |
| Wait before injecting (10 ft kit) | About 2 to 4 hours, until fingernail hard | About 1 hour, until fingernail hard |
| Wait before injecting (30 ft kit) | About 20 minutes | About 20 minutes |
| Working temperature | No range given in the kit's instructions | Condition the paste to 65°F to 85°F before use |
| After the foam cures | Stays on the wall; chisel, sand or grind to remove | Pull the starter tab and it peels off with the ports |
| Finish | Gray strip along the crack, paintable | Bare concrete |
| Extra item needed | Scrap cardboard for mixing | A 4 inch piece of duct tape as a starter tab |
Each kit's product page and technical data sheet
When should you choose the epoxy paste kit?
Choose epoxy paste when the wall is ever damp or when you’d rather pay less. The 10 ft epoxy paste kit is $204.95, against $239.95 for the peel-off version.
The epoxy paste’s data sheet calls it moisture insensitive, so a wall that sweats or wicks a little won’t stop it curing. You still have to apply it to a dry surface, which the kit’s instructions say you can get by waiting a few days or drying the strip with a hair dryer, heat gun or oil-free compressed air.
It’s also the better pick for an unfinished basement where a gray strip along the crack doesn’t matter, or a wall you plan to paint. The kit’s instructions say the surface seal is paintable once the ports are off.
When should you choose the peel-off kit?
Choose peel-off when the wall is dry, the room is warm and the wall will stay exposed, such as a finished space with bare concrete. The paste comes off in one pull, so there’s no grinding.
The peel-off paste’s data sheet says to condition it to 65°F to 85°F before use, and lists its tack-free time as 25 to 30 minutes at 73°F but 1 to 1 1/2 hours at 40°F. In a cold basement, that means a longer wait, and on a damp wall it won’t cure at all.
The injection troubleshooting guide covers what to do if the paste won’t stick or stays soft.
How do you remove peel off or epoxy paste after injection?
Peel-off paste comes off by hand; epoxy paste stays unless you chisel, sand or grind it. With either kit, wait about 3 or 4 hours for the foam to finish before you touch the ports.
- Peel-off paste: pull down on the duct tape starter tab at the top of the crack, and the paste and ports come away together. Its data sheet notes that the more you roughen the wall before pasting, the harder it is to peel, so wire brushing is enough.
- Epoxy paste: knock the ports off with a hammer. The kit’s product page says the paste may be removed with a chisel, sander or grinder, or you can leave it.
ACI’s crack injection bulletin says the surface seal can be left in place (opens in a new tab) if its appearance isn’t objectionable, and that if a cosmetic coating will follow, the surface should be prepared by grinding. That applies to the epoxy paste; the peel-off leaves bare concrete either way.
Which size kit do you need?
The 10 ft kits cover about 6 to 10 feet of crack, and the 30 ft kits cover about 30 feet. Both 30 ft kits include a manual dispensing tool and both say the paste is ready to inject over in about 20 minutes.
- 10 ft kit with epoxy paste: $204.95
- 10 ft kit with peel-off paste: $239.95
- 30 ft kit with epoxy paste: $574.95
- 30 ft kit with peel-off paste: $654.95
For several cracks or one long one, the 30 ft epoxy paste kit or peel-off kit is the better buy. The kit sizing guide helps you measure, and the product chooser covers every crack type.
When is neither kit the right choice?
Neither kit fixes a crack that’s structural. Horizontal cracks, bowing walls, wall cracks wider than 1/4 inch, cracks with one side sticking out and stair-step cracks in block walls need an engineer, not a foam kit.
The foam is a water seal, and its maker says it is not intended for structural cracks. If you’re deciding between a seal and a structural bond, read epoxy vs polyurethane injection first.
Questions
Is the peel-off paste weaker than the epoxy paste?
It holds the ports for the low-pressure injection these kits use. Its data sheet says wire brushing is usually enough for low-pressure work, and that deeper surface prep makes it harder to peel off.
Can I paint over the epoxy paste?
Yes. The epoxy paste kit's instructions say the surface seal is paintable after the ports are knocked off. For a smooth finish under paint, grind it flush first, as ACI suggests before a cosmetic coating.
Does the paste choice change how well the crack is sealed?
No. Both kits use the same polyurethane injection foam, which does the sealing inside the crack. The paste only holds the ports and keeps the foam from squeezing out of the wall face while it cures.
Can I use these kits on a block wall?
No. Injection is for poured concrete walls. Block walls are hollow, and stair-step cracks in block often mean the wall has moved, so have an engineer look first.