Several factors can cause concrete foundations to fail. Before deciding whether to repair foundation cracks from the inside or outside, prioritize reaching out to Crackmasters Basement Waterproofing Specialists over a generic handyperson or plumber. Opting to save a bit of money at the risk of compromising structural integrity might end up being an expensive oversight.

Properly sealing foundation cracks, whether from the inside or outside, can be equally effective. When obstacles like a deck or patio exist, or if the basement remains unfinished, sealing from the inside often proves best. Conversely, if drywall, paneling, or a furnace occupies the space inside, experts recommend an external repair technique.

Should you find yourself uncertain about how best to address foundation cracks, trust the repair expert’s judgement. Factors such as the crack’s location, its type, the depth of damage, among others, determine the best approach. Always ensure a specialist conducts a thorough on-site assessment before you make the final decision.

Foundation Crack Repairs From InteriorFoundation Crack Repair From the Interior

Years ago, repairing a crack involved chipping it out and patching it up. Professionals used a rotary chipping hammer to remove concrete, and then they applied hydraulic cement. Although these methods offered a quick fix, they lacked durability. These repairs didn’t fully seal the crack, leaving it weak. Moreover, the hydraulic cement used didn’t have lasting strength. While people once favoured epoxy resins for such repairs, they now see them as better suited for structural challenges.

Now, the prevalent approach to internal foundation crack repair is crack injection, using either epoxy or urethane. Epoxy injection first seals the inside of the fracture with epoxy paste and then fills the crack entirely with a resin, whether epoxy or urethane. Most experts believe that urethanes provide better waterproofing as they maintain their flexibility.

When Interior Crack Repair is Preferred

Interior Foundation Crack RepairWhen a crack leads to a damp basement, specialists often advise repairing from the inside, and several reasons back this recommendation.

  • Inspecting the entire inner wall from the inside pinpoints the exact leak issue, especially when multiple rod holes might be leaking externally.
  • Repairing from the inside allows for the injection of a polymer into the foundation wall fissure, filling the gaps entirely. In contrast, external repairs only address the problem from the outside.
  • Interior repairs avoid the hassles associated with exterior restorations, like removing soil or dealing with external drainage systems, decks, fences, landscaping, and utility lines. Such outside repairs also carry a higher risk of damaging tiles, utility lines, and root systems.
  • Interior repairs prove more cost-efficient. While an internal injection might cost just a few hundred dollars, removing and replacing soil and landscaping could run into the thousands. This method also cuts down on additional expenses linked to repairing or replacing damaged utilities, fences, decks, and landscaping.
  • You can undertake internal crack repairs in any weather condition, requiring only one person. However, exterior tasks demand dry weather planning.
  • While exterior repairs often rely on concrete patches that might crack and leak, interior repairs use waterproof polymers. These polymers adjust to temperature fluctuations without compromising structural integrity.
  • Interior repairs enhance safety. Excavating holes outside a foundation wall can lead to potential cave-ins or other excavation site accidents.

Foundation Crack Repair From the Exterior

You need to be vigilant about foundation cracks, particularly those external ones that can let in water and cause other issues. While walls and ceilings might present gaps, it’s crucial not to overlook foundation cracks. Ground movement or flaws in concrete often cause internal cracks, while weathering causes external ones. As temperatures shift throughout the seasons, homes become vulnerable to such damage.

Many homeowners believe repairing foundation cracks from the outside offers the best solution. A specialist might remove a small exterior section of the foundation to determine if the entire wall or just the plaster is damaged. To seal an external breach, you should excavate from the wall’s top down to its footing and then fill it using granular clay, forming a solid water barrier.

Since internal fissures can sometimes result in external cracks, always inspect your foundation’s interior thoroughly. Given the nature of the crack, specialists adjust their repair methods. Therefore, conducting comprehensive inspections is essential before finalizing the best repair strategy.

When Exterior Crack Repair is Preferred

Exterior Foundation Crack RepairExterior repair may be more desirable and less expensive in a few of the following instances:

  • Removing and replacing interior walls and fixtures like wood paneling, built-in bookshelves, or brick fireplaces can be costly and time-consuming.
  • If you need to repair a bent wall, address or update exterior drainage systems, or adjust the soil’s composition, voids, or grading around the foundation, you’ll require excavation. Doing this from the outside is best.
  • When part of the foundation lies underground, experts often use a mini-excavator to reach the problem area. In these situations, repairing from the outside becomes logical.
  • To repair foundation cracks, start by cleaning and opening the crack into a V-shape. Then apply quick-setting cement and seal it using a high-performance, polymer-based sealer that can flex with ground movement.

Next Steps

You have options with both interior and exterior crack repair methods. The best choice hinges on specific challenges and conditions you face in your home. From a warranty perspective, the location of the repair—whether inside or outside—doesn’t affect the assurance of quality.

Always weigh the advantages and disadvantages of each approach, considering factors like cost, potential property disruption, and effectiveness. Engaging a professional to evaluate your situation will also provide clarity in making an informed decision.


At Crackmasters, our team has over 20+ years of professional experience with cutting-edge basement waterproofing, basement crack repair, and foundation crack repair systems. A lifetime guarantee backs our foundation repair services. For a free estimate and inspection, contact us today.

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