One of the most obvious places to get a major bang-for-your-buck in a bathroom update is the countertop. However, this can also be an expensive upgrade, particularly if you love luxurious options such as Carrera marble. But if you had a budget-friendly option that required a little elbow grease and some concrete that would result in a marble-esque countertop, would you be interested? Of course you would! You’re going to absolutely love the finished product of a faux marble concrete countertop. Here’s how you do it. (Or, if you love the look of a regular concrete countertop, like this kitchen concrete countertop tutorial, that’s a lovely option as well.)
- White Ardex feather finish
- Grey Ardex feather finish
- Disposable mixing cup, mixing bucket, wooden paint stirring stick
- Putty knife and trowel
- Coarse, medium, fine, and very fine sandpaper
- Gloves (optional but recommended)
- Wet/dry shop vacuum
- 511 Impregnator
- SafecoatAcrylacq in satin finish
This solid surface vanity countertop is fine for what it is; however, because the bathroom is undergoing an entire facelift, the countertop’s beige and brown undertones no longer work for the space.
Remove sink fixtures. (Check out this article on how to remove and install a bathroom faucet, if you’d like.)
Clean the countertop thoroughly with some sort of degreasing cleaner. Let it dry.
If you’re moving from a three-part faucet to a one-hole, you will want to fill in the two outer holes with concrete. As a temporary means of support (to hold the concrete in place while it dries), stick two pieces of duct tape underneath the holes to be filled.
Use painters’ tape to tape off the sides. This step is optional. It helps to keep the wall free from concrete splotches, but you have to remember to remove the tape while the concrete is still wet, or it will be a pain to remove.
To create a subtle marble effect with Ardex feather finish, I recommend doing five or six layers. You’ll need both white and grey Ardex. Use white for the first layer, so your baseline is white. It likely won’t show through after five or six layers, but on the off-chance that it does, white is a good way to go.
Follow the instructions on the Ardex packaging. Measure and pour the powder into a large disposable container. I found a gallon ice cream bucket to work well here.
Measure half of that powder amount for water, and pour the water into your powder bucket.
Mix the water and powder thoroughly. Although the packaging recommended a 2:1 powder to water ratio, I had better luck with roughly a 1.5:1 ratio. This photo shows a 2:1 mix, and it is a little too firm.
Start anywhere on the countertop you want, and begin troweling on the concrete in smooth strokes. If you start on the top of the counter, cover the entire flat surface before moving onto the sides because the Ardex feather finish will start to dry fairly quickly, and then you can’t smooth it out anymore.
Once you’ve applied your feather finish to the flat top, remove the painters’ tape even before moving onto the side surfaces.
Use a trowel or putty knife to spread the concrete on side surfaces.
Apply more concrete than you’ll actually need to the edge corners. When you go to sand the concrete, thin layers at the corners will disappear faster than you think, leaving you with very little concrete coverage on the corners. Beef these up, and you can always sand them down later.
You will want to apply the feather finish around the inside rim of your sink (wherever the solid surface countertop is). This is another place to add in more concrete than what you’ll actually need, so you can sand it down to a smooth surface later.
I did use my fingers to smooth the obvious excess before it started to dry, however. One thing to remember is that rounded surfaces are harder to sand than flat surfaces, so the smoother you can get the wet concrete, the easier the sanding steps will be.
Depending on how your original countertop is designed, you might be looking at a rounded front edge. My first idea for the rounded edge was to simply smear loads of feather finish onto the edge, from the bottom up to the flat countertop surface, and let it dry that way.
I don’t recommend this method, and I’ll show you a better technique later in this tutorial. Let this photo demonstrate the way NOT to do it.
Let the first layer of white feather finish dry for at least 24 hours.
I recommend covering the sink surface with plastic grocery bags taped to the sides of the sink. This will help to keep your drain clear of the copious amounts of dust that occur with the sanding you’re about to do.
Grab your coarse (80-grit) sandpaper, and get ready to sand down the first layer of feather finish. Be sure to wear a mask and protective eyewear for this step; the dust is going to get everywhere. Keep your space well ventilated.
Sand the countertop. The goal is to create a smooth surface without sanding all the way through to the solid surface, although it’s bound to happen with this first layer.
Wrap a piece of coarse sandpaper around a sanding block and use for corners, edges, and any places that you feel need a little more control and care in sanding.
The best way I found to sand a rounded lip is to gently place the sander on the underside of the rounded edge, then rotate the sander up over the rounded edge until it’s on the flat (top) surface of the countertop. This way, you can watch the level of sanding (view the line where sandpaper touches the concrete) for most of the wrist rotation and adjust your sanding pressure accordingly. Then pick up the sander, move it down a few inches on the underside of the rounded edge, and go again. Repeat all the way down the rounded edge.
After the electric sander has done the heavy lifting on the rounded edge, follow up with a piece of coarse sandpaper wrapped around the edge to smooth it out a little more.
Use the sandpaper piece in this same technique around the lip of the sink.
Vacuum up all the dust. It’s everywhere.
The next layer you’ll add is a grey one. Mix up your grey powder in the same way. Note: For your reference, on this small vanity countertop, I only needed about 2 cups of powder (plus water) for each layer.
Trowel on a thin layer of grey feather finish.
Pinch the corners to bulk them up a little more than the surfaces again. I found this easiest to do after the concrete had sat for a minute or two, when it was just barely starting to dry.
After applying more concrete to the inner rim of the sink edge, curve one finger, hook it onto the rim so that the actual side edge hits between the knuckles, and gently run that finger all the way around the sink edge. This was how I found would create the smoothest possible edge while applying the feather finish.
Similarly, apply enough concrete to the rounded edge that there are no gaps, then curve your thumb and run it all the way down the lower curve of the rounded edge. Then do the same with your thumb on the edge’s upper curve.
Clear out the center faucet hole, if any concrete fell in or adhered to the side.
Wipe off any excess while it is still wet. Although it’s possible to wipe off the feather finish after it dries (as long as it’s not sealed yet), it’s much easier to do this while the mixture is still moist.
Wipe off the walls if you opted to not use painters’ tape for protection.
Let this layer of grey dry thoroughly, then sand lightly. Don’t worry about getting this layer perfectly smooth, as you want some grey to come through to create a marbling effect. In fact, the more marbling you want, the more texture or lines you’ll want to leave exposed in this grey layer. (This tutorial shows a very subtle marbling, so the grey layer is not super textured.)
The third layer can be a mixture of white and grey powder. This will add depth to the “veining” in your marble effect. Spread it on thinly, with some texture. Pay attention to the directly of your lines; you will want to keep your trowel marks moving in roughly the same direction, similar to wood grain, so that if and when the lines are exposed, it looks similar to marble.
You will not be sanding this grey-white layer.
Let the grey-white (third) layer dry thoroughly.
Can you see how marble veining might appear when white feather finish is applied on top of this and then sanded down?
Mix up your fourth layer of Ardex feather finish in white, and apply a thin layer. Use your finger to smooth out the corners where countertop meets wall, as these joints are hard to sand smooth.
Decide how much grey you want exposed. This is really a subjective decision – if you want less grey, add thicker layers of white. If you want more grey, make your white layers thin and sand down more to expose more grey. Do what you love and what you want for your own space.
Beef up the corners with white, though, so you don’t end up with a shabby chic version of marble after sanding. That’s not what we’re going for – marble doesn’t work that way.
This “veining” next to the sink itself has turned out nicely. When you find a spot you like, with the grey showing through in a way that really resembles marble, do your best to leave it alone. Generally, the more you sand the area, the thicker the grey lines will become.
On this side of the sink, we’ve ended up a little to blotchy. That will get another coat of white to try again for subtlety.
When you use an electric sander on the white layers, you’re going to be challenged in keeping the edges and corners somewhat white and crisp. This is a good illustration for why building up the corners and edges is a good idea – they are the most quickly sanded down. This doesn’t look like marble, so it’ll be redone with another layer of white as well.
Here is a shot of the overall vanity countertop. It’s beginning to feel a little like marble, but as I mentioned before, there are some spots that definitely need touching up with another layer of white. Repeat the steps for applying and sanding the white top layer of feather finish. Repeat as many times as you’d like, actually – it doesn’t hurt anything to add layers to cover up mistakes. That’s one of the great things about this process, actually.
When you’ve reached a point that you’re satisfied with the faux marble appearance of your concrete countertop (remember, everyone’s preferences for veining are different – go with what YOU like), it’s time to sand it for smoothness. Use 220, 400, 600, then 800 grit sandpaper to get an ultra-smooth finish.
Wipe the countertop thoroughly after each sanding.
Before you seal your countertop, you should apply two or three coats of 511 Impregnator, which will soak into the concrete and help to keep it stain resistance from the inside out.
Apply the impregnator in smooth, easy brush strokes.
Follow the directions on the bottle – let it sit for a few minutes, then wipe off any excess with a clean, white towel. To be honest, there was very little excess for me to wipe up. It seemed to just soak right in.
Let the impregnator dry completely (your countertop will appear splotchy and darker while drying; don’t be alarmed), then repeat another time or two.
After you’ve completed your coats of 511 Impregnator, it’s time to seal your vanity countertop. Because this is a bathroom, where toothbrushes and toothpaste abound, I recommend a food-safe, non-toxic sealer, such as this SafecoatAcrylacq.
Pour a bit onto your countertop, then use your paintbrush to spread. It’s important when working with acrylacq to keep a wet “edge” to your brush – the sealer dries relatively quickly, and brush strokes will show when your brush starts to get dry or you are trying to apply too little of the acrylacq.
You may be tempted to go over a spot with your brush that you’ve already finished, but don’t do this. It will only lead to brush strokes galore.
This sealer will make the feather finish appear slightly darker than it was unfinished.
The satin finish, though, is gorgeous in person. It really makes the marbling effect come to life. (May not translate via photos as well, though.)
Be sure to gently sand with very fine (800 grit) sandpaper between each coat of acrylacq. You don’t need to sand the very last coat, but you can if you’d like. I recommend five, six, maybe even seven coats of sealer. It certainly doesn’t hurt anything and will only protect your surface.
Reinstall a faucet onto your new countertop, and step back to admire the new look. Very luxe.
Who would’ve thought you could DIY your own durable, long-lasting faux marble countertop out of concrete?!
The end result is much whiter, lighter, and brighter than the tired-looking, yellowy countertop from before.
Even in the midst of a bathroom renovation, with the vanity itself under construction, you can start to get a feel for a high-end bathroom transformation just with this marble countertop alone. We hope you give it a try…and love the result.
Note: The author is an experienced, although not professional, DIYer. Neither the author nor Homedit is responsible for any injury or damage that may be a result of following this tutorial.