Sealing Concrete Cracks in Basement Walls

Are you dealing with a damp basement due to leaking walls? Water seeping into your below-grade rooms can ruin living spaces, destroy stored items, and lead to mold growth. However, you can stop this problem by hiring a contractor trained in sealing concrete cracks.

What Causes Concrete Wall Cracks?

Several factors can cause basement wall cracks that allow water intrusion:

• Imperfect construction: New homes often develop leaks if builders don't properly waterproof them
• Aging concrete: Exposure to hot/cold cycles and general aging creates cracks over time
• Unstable soil: Soil issues like erosion, poor compaction, and freeze/thaw cycles undermine foundations

While temporary surface repairs exist, polyurethane injection from the inside provides the best long-term solution. Depending on your situation, trained waterproofing contractors will likely use one of two methods.

Option 1 - Polyurethane Crack Injection

Polyurethane crack injection offers several advantages. Depending on the structure, contractors may be able to do it from either side of the wall, allowing the space to remain in use during repair. Additionally, the polyurethane material reacts with the leaking water to cure into a flexible seal (allowing for slight structural movement over time).

The Crack Injection Process

1. Locate and prepare the crack surface
2. Drill injection holes along the crack at an angle
3. Flush the holes with water to remove debris
4. Install injection ports and inject water to confirm the flow direction
5. Inject polyurethane grout, normally starting at the lowest point
6. Reinject grout a second time
7. Inject a final round of water to reactivate any remaining grout

Contractors need about 1 gallon of grout per 25 linear feet of cracks. Although this process is straightforward, it's not a DIY or handyman project. Always consult a professional to ensure they use proper techniques and materials.

Option 2 - Polyurethane Curtain Wall Grouting

Curtain wall grouting involves injecting an entire wall or section with polyurethane to create a waterproof barrier. This method is ideal when a wall has numerous cracks that are difficult to locate and inject individually.

The Curtain Wall Grouting Process

1. Drill a diamond-shaped grid of injection holes across the wall
2. Beginning at the bottom, inject each hole with polyurethane grout
3. Work up the wall, with each new row of grout flowing over the previous
4. Continue until the entire area is sealed

The injected grout penetrates into the soil behind the wall, forming a water-impermeable curtain. Consequently, this "positive side" waterproofing stops the water at its source. As a result, it blocks any seepage from entering the wall.

Contractors pioneered this technique in the 1960s for leaking manholes, and it's effective on concrete, block, stone, brick, and even wood or metal. They often use it for basements with hard-to-find cracks, previously failed injections, or masonry walls unsuitable for individual crack injection.

The specific polyurethane grout used for a curtain wall depends on soil conditions, voids, and water volumes. Therefore, always consult with a waterproofing professional so they can choose the ideal grout and injection pattern.

Hiring a Professional Trained in Sealing Concrete Cracks

Both polyurethane crack injection and curtain wall grouting are highly effective when trained experts do them properly. With either approach, the injected grout creates a permanent, flexible water barrier that reacts with the leaking water.

Once professionals permanently seal the leaks, you can confidently use your below-grade room without worrying about future water damage. As a result, you'll enjoy your dry, comfortable space for decades to come!

Fill out this form or call 404-618-0438 for a contractor referral today!

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