Skip to Content

How to Fix Crumbling Concrete

How to Fix Crumbling Concrete

Crumbing concrete is caused due to general wear & tear, extreme temperature changes, moisture, or even ingrown roots. It infringes the structural stability of concrete and makes the area look fragile.

The general method to fix crumbling concrete is to remove all loose concrete debris and clean it thoroughly, apply a concrete bonding agent to the area and patch it up with a concrete patcher with some final touches.

Follow the steps below to understand the entire patching process better.

How to Fix Crumbling Concrete

Crumbling concrete might occur on driveways, concrete steps, Patios, Foundations walls, or plastered concrete walls. The general patching steps are the same, with slight variations according to the specific areas.

Proper Items/Tools for a Proper Job

Following is a list of tools that might be required. Acquire them as needed for the steps.

  • Flat Trowel
  • Masonry Trowel
  • Concrete Bonding Agent
  • Concrete Patcher- Quick Setting or Regular
  • Epoxy Resin Bond Concrete Sealers ( Situational)
  • Applicator Gun ( Situational)
  • Edgers (Situational)
  • Screed
  • Float
  • Sponge/Brush
  • Paintbrush
  • Safety Attire & Shoes
  • Tapcon Screw (Situational)
  • Drill (Masonry Rotary Hammer Recommended)
  • Power Spray (If available)
  • Pressure Washer (If available)
  • Garden Hose / Bucket with water
  • Plastic Tub
  • Hauk
  • Broom/Stiff Brush/Wired Brush
  • Grease Fittings (Situational)
  • Wooden Forms (Situational)
  • Vacuum Cleaner (Recommended but optional)

How to Repair Crumbling Concrete (Patios, Driveways)

These are general steps for all crumbling concrete instances. Follow the specific measures for variations as specified below.

 General Preparation

  • Check the temperature first before starting the project. It is not viable to do concrete repairs in extremely cold temperatures. It is best to do these jobs when the temperature is at least above 50 degrees Fahrenheit as a general norm. We recommend doing a 5-day average temperature check before opting for these repairs.
  • Irrespective of the area, the first step to repairing crumbling concrete is always cleaning up the area. Use a stiff broom, stiff-bristled brush, or wired brush to clean off all loose concrete from the area along with any other debris.
  • You might need to use a hammer & chisel in some areas where deteriorating concrete is not coming off easily. There are masonry rotary hammer drills with a chipping attachment to get the job done for large areas.
  • We also recommend using a pressure washer or power spray if available. A garden hose or bucket with water and a sponge can do the trick in the worst-case scenario. There are also commercial concrete & asphalt cleaners that you can use for an extra cleaning kick.
  • Be extra thorough in this step. Failure to remove loose concrete will make the concrete crumble again later.
  • If you are doing a vertical repair, place plastic sheeting on the bottom of the area to catch any future excess patch falling downwards.
  • If this is an indoor job on the walls, place wide masking tapes to not ruin the paint on the rest of the areas. If you are fixing a section for outdoor driveways, use duct tape to mark the area. Do not forget to use masking tapes on the drain cover if nearby.
  • If this is an indoor job on the floor, use masking tapes on the base moldings.

Are Sections Missing/ Do Sections Need Replacement?

  • If big chunks of concrete are missing for outdoor patios, please use wooden forms to make a frame for that area. Make sure you use vertical wooden stakes to provide rigidity to the frame.
  • For entire sections of patios that need to be created new, you will need to dig the substrate, create a subbase of gravel, and tamp it down using a tamper. You will also need to form the area with wooden planks and vertical stakes to rigidify it.
  • This process is needed before applying the concrete paste from the base to the level of the previous concrete. If the new section is horizontally wide, rebars will need to be inserted into the existing concrete.
  • We need to use a masonry drill to drill holes on previous concrete and use a masonry bonding agent to hold the rebar to the concrete. Rebars are compulsory in high-traffic areas. Always opt for rebars wherever you can.

Apply Concrete Bonding Agent

  • Do not skip this step. Concrete bonding agents are required so that the patching mixture later applied will stick on the crumbled area. These products, in simple terms, are the glue that we apply to hold the patching down.
  • Follow manufacturing specifications on the application and the recommended dry time as it varies according to brand.
  • Use a paintbrush to apply the bonding agent to the intended concrete area. We are to create a thick coat that is tacky but not so thick that there are puddles.
  • We can easily find these products in local hardware stores. Popular brands include Quikrete, Elmer’s, Larsen, Weld-Crete, Silka, etc.
  • Some products change the opacity during application. This phenomenon is normal, and they will most likely change to a clear coating at the end of dry time. Please adhere to manufacturing instructions for the dry time needed before applying the concrete patching agent.


The old-school way is to use slurry mix for a bonding agent. You will need to mix pure cement into the water till you have a paste-like consistency.

Use this option in the worst-case scenario. We recommend using a commercial bonding agent made specifically for the adhesion of concrete.

Apply Concrete Patching Agent on Crumbled/Cracked Area

  • There are various alternatives for concrete patching agents. There are epoxy, latex, and mortar mix options. For small cracks, epoxy and latex are fine, but when repairing big chunks of concrete missing, big gaps, or small cracks, mortar mix patching compounds are the best.
  • You can get caulk guns for small hairline cracks and fill the gaps with epoxy patchers or vinyl concrete patchers. It will be a lot faster.
    hairline cracks
  • There are plenty of brands like QuestMark, Sikacryl, Red Devil, MRO Chem, Damtite, Rust-Oleum, Quikrete, etc. Just visit any one of your local hardware stores; the store employees will generally advise on the product to use.
  • Mix the concrete patching agent according to the manufacturing instructions. Most of these are quick-setting patching compounds, so the work time is generally around 45 minutes from the mix. Be quick and precise, apply the patching compounds on the cracks and void areas, and plug them in using a trowel. We recommend doing the patching in two installations. Do the first pour, trowel, and screed if need be, and do a second layer for the finishing.

Apply Finishing Touches

Use your trowel or handheld float to smoothen the surface of the repair. Use edgers as needed to create a sharp line. Once done, take a broom and apply it to the area to develop traction or create a clean look with a wet sponge. If you fixed hairlines crack with fillers, we recommend sanding it down to have a uniform look.

 Protect Your Work

Apply a plastic sheet on the area repaired and wait for the concrete to cure and harden. Spray the area with water 3-4 times a day and leave the plastic sheet on once done spraying.

We recommend doing this for a minimum of 7 days. Remove the plastic sheet once the concrete repair has cured completely.

Apply Concrete Sealer, Primer or Paint Accordingly

After the concrete cures, we recommend sealing it with a masonry sealer. If you want to paint it later, use a primer layer and paint it to your needs.

How to Repair Crumbling Concrete on Steps

  • The first step is to put screws or rebars needed for concrete steps.
  • We can purchase Tapcon Screws through local hardware stores. Screw plenty of them on the previously crumbled area. Remember, the screw should come up about ½ to ¼ inches from the surface. The goal of these screws is small to act as small homemade rebars so that concrete has something to latch onto.
  • If the steps are severely damaged, and the bottom part is completely missing, you can get bigger-sized bolts. Drill those bolts on the floor on both sides of the steps and attach rebars with twist ties.
  • If a big chunk of concrete is missing from the front part of the steps, we will need to create wooden forms which will act as frames for the step. For smaller edge chunks that are missing, forms might not be necessary.
  • For repairing just the upper surface of the concrete steps, forms will not be required. You may need to use some blocks to hold the form into place.
  • Once the above-stated steps are complete, apply a concrete bonding adhesive or fortifier on the area to be fixed with a paintbrush. Follow manufacturing specifications for this. A general norm is two coats. We want the glue to be tacky, but no puddling should be done.
  • Get some quick setting concrete patch and mix it according to the manufacturing directions in a plastic tub or wheelbarrow.
  • Use your trowel and start placing the patch on the area to be filled. Make sure the bottom of the parts is being loaded properly.
  • Once the step is filled, use a trowel to smoothen the surface on the top. If possible, get a small screed to do this.
  • Use your edger to make smooth edges of the steps, and use a handheld float on top to smoothen the area.
  • Plastic sheet the area to keep moisture till the concrete is cured properly.
  • Once the concrete curing period is over, seal the concrete area with a concrete sealer.concrete steps

 For Extremely Damaged Steps

There are deep repair mortars found in the market which we can use to create a relayer on all the damaged steps. Please opt for relaying the whole staircase if the steps are old and disfigured. Do not forget to slope the steps slightly outward to prevent water pooling.

How to Repair Crumbling Plaster on the Concrete-Mortar Wall

  • Get some premixed plaster sealer/bonding agent and apply it to the area with a paintbrush. This product will help the new plaster stick to the wall.
  • Get a bag or multiple bags of readymade plaster mix from your local hardware store. The amount needed will be easily calculated while purchasing the product. Some popular brands are Polycell, Everbuild, Bond it, Patching plaster, etc. The prices generally range from 9 to 20 pounds depending on the volume and brand.
  • Mix the plaster mix with water according to manufacturing instructions.
  • Take a bit of plaster on your Hauk, take your masonry trowel, and apply a thin layer of plaster mix to a crumbled area. A general norm is around ¼ of an inch, but that may vary according to how deep the crumbled area is. Use a masonry trowel to do it.
  • Let this coat dry for about 30-45 minutes and add another layer of plaster mix to the area. Use your trowel to remove any excess and smooth the surface. Our goal is to create a level wall.
  • Once the layering is complete, wait around 7-8 hours for the area to dry. Once the area is dry, you can sand it to create an even layer.
  • You can use sandpaper designed for masonry or an electrical palm sander if there are a lot of places to be fixed.
  • Plaster walls are generally painted so, prep the wall with sealer and put a layer of primer and paint to make it look snazzy.

How to Fix Small Cracks on Basement Walls

  • Buy some Epoxy resin base bonding for concrete systems from local hardware stores.
  • Please read the manufacturing specification while using these products. There are temperature requirements; we cant use some products if the surface isn’t dry, and there are mixing instructions.
  • Clean the area with a wired brush drill to open up the cracks. Mark every 4 -6 inches on the cracks.
  • Separate the port and plugs from each other.
  • Use an applicator gun and insert the epoxy resin Cartlidge.
  • Get about 4 ounces of paste from the gun into a bowl and mix the paste. Use the paste to stick the gaskets on the marked areas. Let the epoxy cure for 10-15 minutes before sealing.
  • Make additional batches of epoxy paste and start sealing the cracked areas. Seal the whole, cracked area. You should only see the gaskets.
  • Take your injection gun with a hose assembly and inject the filler into the ports. Start from the bottom gasket to the top. Once the bottom gasket fills, attach the hose to the higher port and plug the lower port.
  • Follow the manufacturing instruction on time needed for the resin to harden, cure, and remove the gasket according to the manufacturer’s stated time. You can chisel or grind them away. You can also sand the level of the repair to the level of the rest of the wall.
  • Paint the area if needed.
    cracked concrete walls

How to Fix Huge Cracks on Foundation/ Basement Walls 

Big Foundation walls fixes are hard to do DIY, and we always recommend having a professional do it as the structure’s integrity is at the question. Also, the crumbling of foundation walls floors generally relates to a deeper waterproofing problem. We recommend consulting a professional contractor with this.

However, the general steps to understand are as follows.

  • Clean and chisel out all dust, debris, and loose chunks of concrete from the cracks and crumbling. You will need a big masonry drill for this job.
  • You will need to drill multiple holes vertically with Grease fittings. It has a gasket that we can tighten that holds on the concrete. You can pump materials into the crack with the grease fittings. You will need to add a hydro active expansion epoxy or cement gel for these cracks.
  • We brush super slurry or sealer on the crumbled area of the crack. These solutions have crystal ingredients that grow inside the concrete and make the concrete nonporous, and activate the concrete around it. It fills all the nooks and crannies & makes it a waterproof membrane.
  • Once the full crack is covered with a slurry pump, the hydro active expansion gel through all the grease fittings; once you start pumping, the expansion filling starts to fill the wall, and you can see when it’s done, it will pour a little through the upper gasket.
  • Take off any masking tape and let the wall cure. You might also have to check the outside wall area of the crack and seal it with the super slurry or sealer.