How to Repair a Cracked Concrete Patio – Part 2

How to Repair a Cracked Concrete Patio – insert backer rod, caulking and sealing the cracked patio. This project is continued from Part 1.

After applying a bead of the QUIKRETE® Concrete Repair (No. 8620-10) sanded caulk, work it into the crack with a fingertip to seal it against the concrete.

Smooth the QUIKRETE 8620 Caulk into the Concrete Crack

Finish the Concrete Caulk Line

The caulk line now has a U-shaped depression from your fingertip that must be filled to prevent water from pooling in the crack and to present a even surface for a nice looking appearance.

  1. Apply a 2nd thin layer of caulk along the crack.
  2. Pull a putty knife along the crack to smooth the caulk.
  3. Push the putty knife over crack to scrape away the excess caulk.

Scrape Off the Excess Concrete Caulk with a Putty Knife

The crack narrowed as it approached the house. No backer rod is needed when the crack narrowed to less than 1/4″. The crack is fully caulked and finished in this photo.

QUIKRETE 8620 Caulk, Backer Rod and Tools for Cracked Concrete Repair

The crack will be stained to blend with the rest of the patio concrete after it cures.

Patio Slab Edge Repair

The crack in the outside edge of the patio slab is patched using the same method with backer rod to fill the crack and QUIKRETE 8620 caulk.

The foam backer rod is pressed into the surface of the crack:

Cracked Concrete Patio Slab – Corner Repair

The backer rod is seated with a screw driver:

Backer Rod Filler Seated in the Cracked Concrete Slab

The crack is caulked and smoothed with a fingertip:

Concrete Crack Filled with QUIKRETE 8620 Caulk

A second thin bead of caulk is applied, then smoothed and scraped with a putty knife.

Finished Crack in the Patio Concrete Slab

QUIKRETE Concrete Repair Results

The QUIKRETE Concrete Repair No. 8620 caulk did a good job at an unbeatable price. Easy to apply with simple tools and has the sanded texture of concrete. I needed only one 10oz tube to patch the 13 foot long crack. The patch will not be noticeable when I apply a new coat of concrete stain.

My patio slab cracked because the soil foundation settled. I believe the soil and slab movement has stopped as the house is 10 years old. Caulk is best suited for stable slabs and cracks where a weather-seal will suffice. I’m curious to see how well the caulk will hold up over time and if peeling will be an issue.

Emecole 555 – Concrete Patio Large Crack Repair

The other end of my concrete patio slab has a large 1/2″ crack where the poured concrete steps have pulled away. Caulk and concrete would be insufficient because a high strength structural bond is needed glue the slab back together to prevent further movement. I used the Emecole 555 polyurea DIY Slab Repair Kit to mend the slab:

Emecole 555 polyurea Concrete Slab Repair Kit

See the Concrete Slab Crack Repair project for more about Emecole 555.

Take care,

Bob Jackson

Copyright © 2016   Reproduction strictly prohibited.

, , , , , , , , ,

4 Responses to How to Repair a Cracked Concrete Patio – Part 2

  1. dcg November 5, 2010 at 11:55 am #

    Did you try the Emecole 555 yet?

  2. Pam August 25, 2014 at 8:42 am #

    Thanks for the info. I have a pool deck of concrete with large chattahoochee stones, not the tiny ones. The house was built in 1991 in South Florida. I have cracks at several areas on the deck, many of which go through to the concrete slab.
    Can I put stones into the second coat of caulking? Then I would seal the deck with 2 coats of polymer acrylic. Do you think the stones would hold? Thanks for a reply. Any other advice would be appreciated.

    • Bob Jackson August 25, 2014 at 9:29 pm #

      Hi Pam,
      I don’t recommend the caulk concrete repair for the deep cracks in your pool deck because caulk is just a surface sealer and provides no strength. I used the caulk crack sealer mainly out of curiosity and it’s OK for small cracks if the slab is stable.

      A better option is a structural concrete crack repair product like Emecole 555. Carbon fiber stitching dogs can be set in the slab surface for extra stability. Then you can lay new stones and it’ll look as good a new.


Leave a Reply