Strong-Plug^® Rapid-Acting Leak Stop Cement

A hydraulic cement that hardens on contact with water. Press it into an active leak in a manhole, tank or pipe and hold it until it sets.

<1 minfinal set

1,000+psi compressive strength in 1 hour

14,000 lbpull-out strength (ASTM C234)

Stop the water first

Hold it in place, and it sets. Strong-Plug^® is hand mixed and hand applied. Use it as a slurry, or press it in as a dry powder and let the leaking water harden it. Once it sets, Strong-Seal^® products can go right over it.

2 waysSlurry or dry powder

Mix to a slurry, or apply dry straight to the leak. No mixing needed for dry.

2,500+ psiIn 24 hours

Over 1,000 psi in 1 hour.

STRONG-PLUG 50 lb bucket

No lossSulfate resistant

No mass loss after 15 cycles at 2,000 ppm sulfate (ASTM C267).

100 cyclesFreeze/thaw tested

Passes ASTM C666 with no damage.

Five steps to a stopped leak

CleanPressure wash to a sound surface, 3,000 psi minimum. Remove loose brick, mortar and concrete.
Open the crackChip small cracks wider with a hammer and chisel so the slurry or dry pack can fill them.
MixFor slurry, use 3 to 4 fluid ounces of water per pound, water first. Mix only what you can place in 1 minute. Dry powder needs no mixing.
Apply and holdPress it firmly into the leak by hand or trowel. Hold it in place until it sets. With dry powder, the leaking water hardens it.
Plug weep holesIf you used weep holes to steer the water, plug them last the same way. No special curing needed.

Then line: once Strong-Plug^® sets, Strong-Seal^® products can be applied right over it.

After the leak stops

Strong-Plug^® is the first step in a manhole rehab. Once the water is stopped, rebuild what’s damaged and line the structure.

Next, patch and rebuildStrong-Seal QSRFast-setting mortar for benches, inverts and voids. Final set in 15 to 30 minutes.See QSR ›

Then line the structureStrong-Seal linersSpray MS-2^®A, MS-2^®C or High Performance Mix over the repaired structure to stop infiltration and restore strength. Pick by how much corrosion you see.See the liners ›

Meet Fernco Infrastructure

An overview of our manhole rehabilitation and trenchless pipe repair solutions.

Specifications

Part number	STRONG-PLUG
Packaging	50 lb bucket
Final set	Under 1 minute
Compressive strength (ASTM C109)	Over 1,000 psi at 1 hour, 2,500 psi at 24 hours
Flexural strength (ASTM C293)	Over 1,200 psi at 28 days
Freeze/thaw (ASTM C666)	Pass, no damage, 100 cycles
Bond strength (ASTM C882)	Over 2,000 psi at 28 days
Sulfate resistance (ASTM C267)	No mass loss, 15 cycles at 2,000 ppm
Pull-out strength (ASTM C234)	14,000 lb
Yield per bucket	0.45 ft³, or 10.8 ft² at ½″ thick
Made with	Hydraulic cement, masonry sand and performance admixtures
Water	3 to 4 fluid ounces per pound for slurry; none for dry application
Typical structures	Manholes, tanks and containment, tunnels and pipelines, wastewater facilities

Common questions

Slurry or dry?

Either. Slurry is mixed and pressed in by hand or trowel. Dry powder goes straight onto the leak and the infiltrating water hardens it. With either one, hold it in place until it sets.

How much do I mix?

Only what you can apply within 1 minute, mixed near the leak.

Can I line right over it?

Yes. No special curing is needed. Once it sets, Strong-Seal^® products can be applied right over it.

What about big leaks?

Some leaks need weep holes to steer the water while you work. Plug those last. Severe infiltration may need pressure grouting.

What weather can I apply it in?

Don’t apply below 40°F, on frozen surfaces, or if the surface could freeze within 24 hours. Keep the material under 90°F and the mix water under 80°F. Chill with ice if you need to.

For distributors

Interested in carrying Fernco Infrastructure?

Fernco Infrastructure covers manhole, structure and pipe rehab with three product lines. Add them to your line card to serve municipal and contractor customers.

Strong-SealCementitious mortars, liners and grouts for manholes, structures and culverts