How to Seal Cracks in Concrete

Structural Damage in Concrete

Concrete repair is simple and economical with the new advances in technology. It is no longer necessary to pour new concrete to fix a simple crack. This how to will talk about repair as well as diagnosis to prevent future problems.

Things You'll Need

• Epoxy injection kit
• chisel
• hammer
• wire brush
• sand
• plaster sealant

Instructions

1. 

   Cracks in a floor can be a real hassle, however, cracks in a basement wall can be dangerous. Cracks can occur during normal settling of a house, extreme temperature change, or commonly landscaping issues.

2. 

   Before trying to seal any crack it is important to diagnose the cause. If you have cracks larger than one inch you could have a structural system failure. Diagnosis is an important part of repair because, you will then know how to prevent future problems.

3. 

   A structural crack can be repaired with a flexible sealant but, this can make it difficult to diagnose problems later. A flexible sealant can stretch and you may not notice that a crack has become larger. Additionally, using a flexible sealant does not address the causes of major settling or frost heaving which need to be corrected immediately.

4. 

   For small cracks under one inch. Clean the concrete, use a wire brush to remove dirt and debris. Wash with water and allow to dry. This makes sure the epoxy sealant will adhere to the crack. If you are sealing the crack with a plaster sealant chip a inverted V into the concrete with a chisel and hammer.

5. 

   Mix the epoxy or plaster sealant using the manufacturers instructions. Some sealants are in a dispenser which mixes the appropriate ratio automatically.

6. 

   If you are filling an expansion joint fill it with a backer rod specified by the sealer manufacturer. Sand may be used as an easier filler for cracks if you are filling a crack in a floor. Sand should stop about 3/4 of an inch from the top of the crack. Apply your epoxy or plaster using the manufacturers instructions. Once that has dried you can apply a bead of caulk for finishing if you desire.

Tips & Warnings

• Use the manufacturers instructions when applying epoxy or plaster sealants.

• Wear gloves as epoxy can be harmful if it contacts your skin.

• Epoxy is dangerous and should not be ingested. Call the poison control hot line if this happens.

Resources

• Concrete Sealer
• Video on selaing cracks in concrete