renovate  maintenance  how To Repair Cracked Concrete
Unsightly cracks in concrete not only detract from the look of a garage or patio, they can also lead to further problems as moisture seeps into the concrete.
Luckily, theres an easy way you can repair a cracked concrete slab or wall and prevent further damage down the track.
Sikadur Concrete Fix is a two part epoxy adhesive and filler that can be used as a bonding bridge adhesive paste for concrete and most building materials.
Its simple and easy to apply and can be used for repairing cracks, holes and voids in concrete floors and walls.
It also works as a structural adhesive for a range of materials including stone, ceramics, fibre cement, masonry, metal and timber.
To repair cracks in a concrete floor, first ensure that the area is free from dust, grease and surface contaminants.
Concrete fix can be applied to both dry and damp surfaces, but standing water in any voids, pits or pores should be removed prior to application.
While wearing safety glasses and chemical resistant gloves, pre-mix both parts separately, then mix equal parts of each together in a suitable container. Mix thoroughly for three minutes with an electric drill and paddle mixer.
Use a trowel to apply concrete fix to the prepared substrate and smooth it into the crack or to form the desired shape.
Apply Sika Concrete Fix to corners using a shaped trowel
The paste cures rock-hard, so make sure you clean all tools and surfaces using Sika Colma Cleaner before it hardens.
How Do I Clean Everything Up After Making My Concrete Repairs
Resin based materials are usually hard to clean and the solvents used to clean them are pretty harsh on the hands. Rizistal however have delivered a solution which you will be able to see in all of the product reviews mentioned above. It is called Safer Solvent, and it is called that because it is!
Dip a rag into the safer solvent and clean your tools easly. The safer solvent can also be used to wipe your trowels down as you smooth over the repair mortars we have mentioned above. As they are all resin based, they tend to stick to the trowels which makes it hard to get the surface smooth.
Use safer solvent to clean tools down after working with epoxy repair mortars
We hope this project has helped you solve a problem that is experienced by thousands of home improvers every year.
Concrete is perishable, it will deteriorate very quickly when it is allowed to crack and the only method of repairing it properly is with epoxy repair mortars. We only recommend Rizistal mortars and concretes because we have worked with them for a couple of years but there are many others out there so please do go and have a look round.
All project content written and produced by Mike Edwards, founder of DIY Doctor and industry expert in building technology.
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Options For Repairing Your Patio
REPLACEMENTThe oldest and most expensive method for repairing a sinking concrete patio is to jackhammer it into pieces and start over. Once the patio is broken up and loaded into a dump truck, the ground is leveled, the forms are installed and a new patio poured.; One of the downsides to doing it this way, besides the cost, is the disruption to your landscaping and the very real possibility you will need to also repair your landscaping afterward.; Concrete workers want to take up the concrete quickly so its likely theyll use a skid-steer loader to remove your back patio. This means they will be driving that mini-tractor back and forth over your lawn to take the concrete pieces to a dump truck parked in front. If patio replacement still sounds appealing, keep in mind that once the concrete is poured, you cant use the patio for a few days while you wait for it to cure properly. And if hot weather is in the forecast while its curing, expect to be out watering the new concrete to keep it from curing too;quickly.
There are your three options for repairing a sinking concrete patio.; Feel free to contact us if you would like a free estimate on polyurethane concrete raising.; We have the experience and expertise to handle this kind of heavy lifting whenever your concrete patio, sidewalk or driveway needs to be;raised.
Ready to get started?
How Do I Fix It
So, what causes a patio to settle in the first place? Prior to the concrete being installed, the ground is prepared by compacting the earth underneath with heavy machinery. In most cases, this compacted surface will either be gravel or at least covered with a layer of gravel. These steps are taken to prevent the ground from settling under the weight of the patio installed above. However, sometimes settlement is inevitable due to weather conditions, namely rain water washing away the soil underneath. Also, sometimes the compacting is not done correctly or thoroughly enough.
How Do I Mix Epoxy Repair Mortars
All epoxy repair mortars come in tubs with ready measured amounts of resin aggregate and hardener. The hardener is tipped into the resin aggregate and a mixer paddle is used to get a good, uniform mix. It takes about 4 6 minutes to mix a 20Kg tub of epoxy mortar.
Mixing epoxy repair concrete with a mixer paddle
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The Concrete Repair Process
In general, repairing a crack in concrete is pretty straightforward. Once the area is clean and completely free of dirt and oil, the steps are as follows.
Add The Concrete Crack Filler
Cut off the end of the applicator tip. Shake the crack filler container if necessary. Some crack fillers will separate, so squirt a small amount of filler onto a piece of cardboard until thicker filler emerges. Force a bead of the filler into the crack, slowly drawing it along and making sure that the filler fully settles into the crack before moving on.
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How To Fix Cracked Concrete Patio
When you go out to sit in your backyard, the last thing you want to see is a cracked patio. Cracked patios are an eyesore and most people have no idea what to do to fix it.
Well go through why your patio gets cracks and what you can do to repair it so you can start enjoying your backyard again.
Removing A Difficult Single Paving Brick From A Brick Or Block Paved Path
If you cannot lever out the offending paving brick with the tools suggested you may only have one option left and that is to remove it as you would remove a single brick from a brick wall or a single tile from a bathroom wall.
Paving bricks can be removed in the same way as wall bricks
Drill a series of holes in the brick with a good drill and a 7mm masonry bit. When the brick is weak enough you can hit it with a hammer and chisel to break it up. It can then be pulled out piece by piece.
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Deep Clean The Concrete
The next step is cleaning the slab of concrete. This will make it look better, but there are other advantages, too. If theres dirt or grime sitting on top, then the leveler that youll apply later will not stick as well as it could do. And while that might not have an immediate impact on the repair job, it can have a detrimental impact over time. You can clean the slab with whatever you have in the home even soapy water and a brush will do the job.;
Option : Resurface The Top
If replacing the patio doesnt sound like your cup of tea,;resurfacing it might sound like a better option. However, resurfacing the patios top only hides the real issue. While cracks and furrows may now be out of sight, the initial problem of sinking and settling has left voids under the patio, and these holes will still exist. Severe voids will cause the patio slabs to rock from side to side, causing an annoying, and potentially dangerous, situation.;Also, should the edge of your resurfaced patio be a part of a step, this step will now be higher, perhaps not meeting local codes and posing a hazard.
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Why Does Concrete Crack
There are several reasons why concrete cracks, with the most common being drying shrinkage. Concrete, when placed in the plastic state, is at its largest volume. As the concrete sets and hardens, it begins to shrink. On average, concrete shrinks 1/8 inch in twenty feet.
Concrete is typically designed for compressive strength and has significantly lower tensile strength. If the internal tensile stresses are greater than the tensile strength of the concrete, a crack can develop.
Get Safe Smooth Concrete Surfaces For Your Home
Uneven, cracked concrete is unsightly and unsafebut theres no need to put up with that problem. Our friendly, professional team will help you get your driveway, walkways, steps and patio flooring back in tip-top shape. Youll love how our High Density Polyurethane Lifting Foam makes your concrete look and perform beautifully.
Insert Foam Tubing Into Large Cracks
The crack I had to repair was about 1/2 inch wide.
Although Sakrete crack filler can be used for cracks up to this size its best to fill in large gaps with the foam tubing.
The foam tubing should be slightly wider than the crack to create a tight fit. I used a 5/8 inch wide variety.
Place the tubing in the crack and push it down. There should be a 1/4 inch space between the top of the foam tubing and the top of the concrete crack.
This 1/4 inch space is where the concrete crack filler will be poured.
Click on this link for more details on the polyfoam caulk saver.
Its made by Frost King who also has a ton of other great weatherizing products.
Check out their website because youll get a lot of great ideas of how to keep the cold weather from increasing your heating bill.
Ground Movement As A Cause Of Cracked Paths
The initial cause of a crack in a path, concrete or otherwise, is almost always ground movement. Notwithstanding the number of objects dropped onto paths every day, unless you are determined to break up the concrete with a sledge hammer or a kango hammer, it is very unlikely you will break a path simply by dropping things on it.
The ground under your feet is moving. Maybe only a couple of mm per year, but it is still moving, and it is moving in every conceivable direction. The tectonic plates that make up the earths structure are slipping and sliding about all the time as the earths core heats up and cools down.
This heat differential causes expansion and contraction in the earth, just as it does with every substance known to man. This movement then causes cracks.
Even the surface heat of the sun, when it dries the earth out quickly, causes cracks and as we have said beforeIf your path is not flexible enough; it will crack.
Even the ground cracks with temperature variation
Once cracked, the process starts and trust us, cracks never get smaller on their own!
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Is It Worth Fixing Or Should It Be Replaced
Concrete that is cracked only on the surface, or has hairline cracks where both sides of the crack are still level can be successfully fixed. See basics of concrete repair and troubleshooting
Cracked concrete should be replaced if due to the three conditions listed below. Any patching material used to fill these types of cracks will only be a short term fix. You definitely would not want to patch these cracks and then spend money resurfacing the concrete or doing a decorative topping.
How To Mend Cracks In Concrete Paths
For more advice on mending cracks in concrete we have a whole page dedicated to the subject. Click on this link to see how to make permanent repairs to concrete paths and drives.
Epoxy resin mortar can be used to repair cracks in concrete
You will see how epoxy resin mortars can be used very effectively as a substitute concrete for repairing concrete paths and drives ensuring, because of the flexibility of epoxy mortars, that cracks do not develop again.
You will also see a range of materials developed to protect your patios, paths and drives against movement and cracking as well as a number of retrospective repair measures.
Common path materials such as stone slabs, concrete slabs and block paving slabs are ideal for making paths
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A Repair For Cracked Concrete That Almost Looks Perfect
Q: Tim, I need to replace a cracked section of my concrete driveway. My primary concern is matching the color and texture of the new patch to the existing driveway. It doesnt need to be perfect, just close. How does one accomplish this? Ive read your past concrete repair columns, so I understand how to mix, place and finish the concrete. Also, what do contractors use to paint the concrete to make it white?
Donn R., Clemson, S.C.
A: Many readers may be facing the same conundrum as Donn. Maybe theyre trying to match a wall stucco patch. Or perhaps they want to repair the mortar between brick on a home.
Im sure everyone has seen garish repairs where the new patching material stands out like a red wine stain on a white blouse. Its possible to get close when doing these types of masonry repairs, but its next to impossible to get a perfect match. If youve got patience and many dont you can really come very close to achieving perfection.
My advice is to do a thorough cleaning of the concrete before you start. You can accomplish this using a pressure washer equipped with a 15-degree tip at the end of the wand. Cleaning the concrete allows you to see exactly what you’ll be matching.
Pay attention to the different colors of the sand as well as the grain size. You may have to mix sand from different sources and blend them to get a close match. You have to get the sand right.
What Else Will Cause Cracks In Concrete
You know the old saying build your house on stone and not on sand or less cryptically the better the site is prepared and compacted the less likely your slab will crack, if the ground has been disturbed in any way or if you have to level the site then good preparation.
So what is good preparation? That will depend on the ground if it is a natural state and the topsoil and grass and any weeds or old tree stumps have been removed then a layer on road-building gravel with a thin layer of sand would do the job as long as the road base material is compacted there is no need to compact the sand or fine crusher dust.
Another thing to be mindful of is the correct placement and the use of a vibration tool to settle the concrete and leave no voids or hollows in the concrete the aim is to have a uniform thickness over the whole slab area.
Steel reinforcement can prevent concrete cracks if the right size is used for the expected load on the concrete. A footpath or sidewalk will carry pedestrian traffic but I wouldnt want to drive a truckload of concrete over it. Sizing of the reinforcement is critical to the life and therefore the structural integrity of the concrete.
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Why Does Concrete Buckle In Heat
Concrete expands when it gets hot, and when the concrete has nowhere to go, it buckles. The technical term is called thermal expansion. You may have heard the term expansion and contraction before. Almost all building materials will expand when they get hot and contract as they cool. Simply put, this means they grow a bit in heat and shrink when they cool. And concrete is no different. Heat causes concrete to expand as the material heats up and this expansion has to be accounted for during construction.
Concrete buckling can be caused by a difference in temperature throughout a concrete structure or by a rapid temperature change. Heat will expand concrete while an uneven temperature will create tension. But both warm temperature and variances in temperature can result in buckling.
Concrete is one of the most commonly used building materials in the world for both commercial and residential projects. One of the biggest issues when working with concrete is buckling, but why doesnt all concrete buckle in the heat. Its mainly due to relief cuts being used which allow for some expansion and the aggregate thats been used. Some aggregates expand a lot more than others so this should be accounted for in your design.
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