One of the most common questions we are asked is can cracked concrete be repaired. The industry answer is yes with disclaimers. Typically, concrete is about 4 inches thick and often is steel reinforced. If 4 inches of steel reinforced concrete can crack, there is a pretty good chance that anything you place on top of it will crack as well which is called mirroring. The crack just comes back as the underlying crack continues to move.
Using epoxy injections to weld the two slabs back together is fairly successful but you can still see the epoxy repair. Contractors will often cover the repairs using Micro-toppings a polymer, sand and cement application applied in a desired color. Micro-topping’s are extremely versatile to include a stone and texture finish in an endless array of colors and stains.
There is also Quartz/Epoxy Systems that are far more durable made from the 4th hardest mineral below diamonds. Quartz Epoxy and injections are made with an epoxy base combining epoxy ejection and Quartz/epoxy finish makes for a pretty indestructible surface.
Another popular re-surfacing system is Grind, Stain and Seal. These are exceptionally beautiful applications that use the characteristics of your existing concrete along with the natural mottling of the stains to make one unique and beautiful work of art. This application does not require a topical application other than the stain and sealer. Most clients like its look even if there are cracks showing. It just looks a little more rustic and in Colorado that is usually a good thing!
But hold on, didn’t you say that with epoxy injection, the cracks could mirror back thru the re-surfacing application? There is always that possibility yes but not always. Well then what can I do? To properly answer that question, we need to review why the crack could potentially come back which requires a little more knowledge about concrete itself.
Beyond the concrete’s psi, which is how many sacks of cement is in each yard of concrete, what type of steel was used of mesh or re-bar and what size the aggregate that was used to make the concrete are all important factors but the most important deterrent to avoiding cracks is the control joints. You might ask what are control joints?
As a kid you may remember skipping down the sidewalk and jumping over the cracks to avoid breaking your Mother’s back. These crack’s are control joints. In a walkway they are spaced about every 4 feet. In a large concrete area such as patios and driveways they have a maximum spacing of 10 feet. If you have a greater than 10′ x 10′ slab or no control joints at all, you will get cracks.
So injecting them with epoxy will help to weld the slabs back together but if you don’t have control joints these cracks will invariably mirror back into the slab. So once you inject the epoxy, it is best to whenever possible to create control joints near the repair or even better in the repair. This is accomplished by using a small right angle grinder and a diamond crack chasing blade. It is a “V” shaped blade that creates joints that look like the joints on your driveways and walkways if you go deep enough with them.
Here at Concrete Restoration Systems LLC, we use the negatives of a concrete slab to our advantage. Take below this residential patio that was about 30 feet wide by 30 feet wide and had no control joints at all. If you look closely you can see cracks running in every direction. So we used a right angle grinder and a diamond crack chaser and started with the existing cracks opening them up to create a joint. We then craved a flagstone pattern off those main cracks creating a unique stone pattern.
We then injected the epoxy into the crack joints to weld the slabs back together. You could use any of the application described above but for this patio we chose grind, stain and seal application in smokey beige stain. We then stained all of the joints with a midnight black exterior concrete dye and WOW what a difference! You can’t even tell where the original cracks were. If there is any future movement, it will be in those control joints and unnoticeable.
Its not just concrete renovation, it art! We invite you to visit our website for more creative solutions to your concrete needs or call us at 303-435-3334 for a free consultation.