The Concrete Network

Decorative concrete expert, Chris Sullivan, provides in-depth answers to common problems associated with acid staining concrete. Find answers to common questions and ask your own questions.
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How to Fix Shrinkage Cracking in Concrete Overlays

Why did this integrally colored stampable overlay crack so drastically? It was applied at 8 a.m. on a hot July day. The air temperature was 85 F, but the surface temperature was over 100 F.


Fixing White Streaks in Concrete Overlays

I used an 18%-solids water-based acrylic sealer on an interior stained microtopping. Certain areas of the floor remained white and hazy. Why did this happen, and how do I fix it?


Cause of Shadowing Through an Overlay

We did a "rough trowel" overlay on a driveway in Pennsylvania, and three weeks after the job was complete dark marks appeared. At first, they would come and go, but now they are permanent. When the homeowner washes his car, the water that gets on the driveway surface also starts to darken the overlay. We think that moisture from underneath the overlay and penetrating from the top in areas where the overlay and sealer have chipped off is causing the darkening. We are now looking for a fix to this problem.


Color Changes on a Black Concrete Overlay

We installed an overlay and applied a water-based black dye and an acrylic sealer. Now it's three months later and the customer would like us to stain the floor. Do we have to apply another overlay, or can we stain the dye?


Using Microtoppings and Stencils to Rejuvenate Ugly Concrete

I have a poured concrete walkway that is sound but worn and ugly. I have gotten quotes for overlaying it with brick or flagstone, but both will raise the level of the walkway too high (people will trip) and they cost too much.


Leveling Concrete Floors with a Colored Overlay

My wife and I are building a home on St. Croix, in the U.S. Virgin Islands. The floor was poured some time ago, and is rough and uneven. We plan on mixing concrete slurry to level the floor. Is there a pigment we could mix in with it to color the floor?


Overlays over Wood Surfaces

We have experience resurfacing concrete with microtoppings and polymer overlays, and we are now just starting to do this process over wood—either interior floors or upper-level patios that do not have enough clearance for concrete. What is the best practice for this process?


To Overlay or Not to Overlay

I am getting ready to resurface concrete in front of two double garage entries. I have been told to have the concrete resurfaced with an acrylic overlay. But I have an estimate from a contractor to resurface using a cement-based overlay.


Concrete Coloring Techniques for Tinted Overlays

I have not had much success tinting overlays on site with tint packs. What is the best way to tint overlays to ensure color consistency?


Fixing Cracks before Overlay Application

What is the best method for fixing cracks in concrete prior to applying a decorative overlay?


Smooth Finish Overlays Installed over Broom Finished Concrete

I have broom-finished concrete and want to acid stain it. All the acid-stained floors I have seen, and like, are smooth with hard-troweled finishes. Is there anything I can do to change my broom finish to a smooth finish so the stain will look better?


Don't Use Overlays to Fix Bad Concrete

Our condominium board plans to have a decorative concrete overlay applied to our 35- year-old concrete walkways, which have existing cracks and many unlevel areas. That concerns some of us. The board members want to apply a 1/8- to 3/8-inch overlay, but that doesn't seem to be thick enough. Please advise. Our location is right on the Gulf of Mexico, so the walks are exposed to a coastal environment.


What Type of Pool Deck Overlay Will Stay Cool?

We need a product to resurface a concrete pool deck in a community complex in Las Vegas. The summer heat is unbearable, and the concrete gets so hot you can't walk on it. I have heard about a product called Kool Deck, but pool stores tell me it's really just a paint. Can you recommend a product for our needs?


Moisture Causes Microtopping Failure

Q&A on the cause and solution to a bubbling microtopping due to moisture emission in the slab.


Placing Overlays over Tile Floors

What is the best self-leveling concrete overlay to apply over ceramic or clay tiles? Do the tiles need to be treated before applying the overlay?


Shadowing Through a Microtopping

What would cause these problems, and what can be done to remedy to them?


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