Project Guide

Repairing Cracked Concrete

Project Level: easy

Project Length: 15 Minutes

Products Used

Concrete Crack Filler

Data Sheet

Concrete Repair Tube

Data Sheet

Hybrid Polymer Non-Sag Sealant

Data Sheet

Hybrid Polymer Self-Leveling Sealant

Data Sheet

Tools Needed

Project Guide – Repairing Cracked Concrete

Why Do You Seal Cracks?

Cracks in concrete indicate an underlying problem that has caused the slab to shift. The most common issue is soil instability caused by moisture intrusion, improper site preparation or poor soil conditions. Most cracks are “active, meaning that patching with a cementitious product is a losing battle – the crack will appear again until the underlying issue is remedied.

Once a crack appears, the most important thing to do is seal it with a flexible material to prevent moisture intrusion which could further accelerate the instability causing the crack.

Choosing the Right Product

Many crack repair products can solve the same problem – knowing how to choose the right option for your project is the first step.

Latex-based products, including Sakrete Crack Filler and Sakrete Concrete Repair offer good performance – suitable for cracks up to 3/8” deep and 1/2″ wide. Latex-based products offer easy clean-up and will last for a couple of years depending on application conditions.

Polyurethane-based products, including Sakrete Non-Sag Sealant and Sakrete Self-Leveling Sealant offer better performance with a superior bond and flexibility for cracks up to ½” deep and wide. Polyurethane-based products require acetone or similar chemicals for cleaning but deliver superior durability and longevity.

Project Prep

The most important consideration is that the crack is large – and clean – enough to accept the crack repair material chosen for the job.

  1. Estimate the amount of material required. One bottle of Sakrete Crack Filler will seal about 35 linear feet. All tube products will seal about 12 linear feet, depending on depth and width of the crack.
  2. Use the Crack Repair Calculator  for fast results.
  3. Use a narrow chisel to widen the crack to a uniform width and form into a “V”-shaped channel. This is especially critical with narrow cracks.
  4. Clean out the crack with air or water to ensure all particulate is removed. Any dust or loose concrete can act as a bond breaker.
  5. Check the depth of the crack. If it exceeds 3/8” deep, back-fill with sand or closed-cell backer rod.
  6. Use the Slab Repair Calculator for precise estimates of the amount of product needed.

Project Tip: Use the Sakrete App to measure, estimate and purchase materials for the job straight from your phone.

Application

All repair materials are ready to use straight out of the tube – just shake, load and apply!

  1. Cut the tip of the repair product tube to the same width as the crack, pierce the inner seal and load into a caulk gun (if applicable). Sakrete Crack Filler is applied straight out of the bottle!
  2. Apply the material in a steady bead along the crack. Note that all repair materials will “settle” into the crack, so expect to apply a second layer. Do not over-fill.
  3. Using a wet sponge (for latex-based products) or acetone (for polyurethane-based products), smooth out the material to remove excess and match the level of the slab.
  4. Wait 15 minutes, then apply a second layer, if necessary.
  5. Allow to cure for at least 24 hours before opening to traffic. See instructions on product for specific curing requirements.
  6. Generally-speaking, latex-based products are paintable after 7 days. See instructions on product for specific curing requirements.

Project Tip: For best results, cracks should be inspected annually and re-sealed as necessary to maintain a good seal against moisture.

Related Projects
Repairing Thin Concrete Damage