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Foundation Crack Repair Methods – Epoxy vs. Urethane Injection

Ever since poured concrete has been used to form foundation walls, cracks have been a main source of wall seepage. Cracks happen for a lot of reasons — foundation settling, external vibrations and over-saturation of the soil among them.

Not all cracks leak, but all have the potential to leak if the conditions are right. However, if a crack leaks once, you can pretty much count on it leaking again with each good rain. Repairing the crack can not only save you a lot of time mopping up water, but more importantly, can prevent mold and mildew problems in your home.

The easiest and most economical way to repair wall cracks is from the inside by injecting sealant into the crack that will stop the flow of water from the outside.  Your basement waterproofing contractor will first attach plastic injection ports to the crack at intervals along its length.  A surface sealer is then applied, usually Epoxy, over the entire crack to hold the injected material inside until it fully cures.

Finally, the contractor fills the crack by injecting sealant through each port.  Two types of material are commonly used for this purpose, Epoxy and Urethane.  Epoxy is the old-school method, still used by some contractors; Urethane offers significant advantages to the homeowner.

Epoxy Injection

Epoxy was used exclusively by basement waterproofing contractors for many years to inject wall cracks for waterproofing purposes.  A few companies still use Epoxy as a primary waterproofing application because it forms a strong bond with concrete. However, unless a “structural solution,” such as wall bracing or resistance piers, is part of the job, the epoxy will still be subject to further shifting or settlement of the foundation.  Because the epoxy is rigid, this movement will cause it to crack and water seepage will return.

Injecting a flexible material such as Urethane is now the preferred method.

Urethane Injection

When the traditional method of crack injection was popular, basement waterproofing contractors could not fill an actively leaking crack with epoxy because it wouldn’t adhere to wet concrete.  This often meant that a homeowner would have to wait for the rain to stop and the ground to dry out before leaks could be fixed.  Today’s more advanced contractor uses Urethane, an expanding sealant that uses water as a catalyst to form an impenetrable gasket to fill the crack all the way through to the outside soil.

The greatest advantage of Urethane, however, is its flexibility.  When a repaired foundation shifts, as it likely will, the flexible urethane maintains contact with the concrete and moves with the wall. Epoxy, on the other hand, being rigid, will tend to crack and expose the basement to renewed leakage.

Despite the advantages of Urethane, some basement waterproofers still use Epoxy and tout its structural benefits.  If you’re considering using one of these companies, you should ask the representative if their company will warranty the Epoxy injection as a structural solution when not performed in conjunction with expensive bracing or piers.  The answer will probably be “no.”  Also, ask what the follow-up repair will be if the repaired crack leaks again.  Surprisingly, they’ll probably tell you they’ll use Urethane, so why not get it right the first time?

Until the mid-1990s, Epoxy was the only thing available to basement waterproofing contractors to fill cracks. When Urethane became available we quickly realized its potential and began using it exclusively.  Since then, we’ve successfully stopped basement leaks for thousands of satisfied homeowners by filling cracks in the more effective and longer-lasting method.

Filling cracks in foundations was how U.S. Waterproofing got its start, so why not listen to the advice of the company that has injected more cracks than any other waterproofing company over the past 30 years!  Contact us at Le Fong Contractor to learn more about the right way to stop foundation leaks.