How to waterproof polished concrete floor

How to waterproof polished concrete floor

Would you like to have a polished concrete floor, but you don’t know how waterproof it is? Or maybe you’re planning for a room that has water use, but don’t know how to get the slab waterproof?

I chose these two questions as the answers will be for two different problems. The first question is about a situation where the polished concrete is already there, but you don’t know what kind of water use it can handle.

The second question is something we have many ways to solve as nothing might be built yet. It’s natural to have more solutions at that point.

How is polished concrete done? There is an article about that in the link and there is also one about honing concrete if you’re interested in the subject.

Here I will concentrate more on the other things such as sealers and the final part will be the waterproofing.

How long do polished concrete floors last

Before we get to the business it’s good to know how long does polished concrete last. It will help us to see the worth of waterproofing properly.

It will also show how proper care is important to protect the value of decorative concrete. As we all know, it will last as long as we take good care of it.

If there are no structural defects on the concrete slab or anything else that might cause the slab to be damaged, the polished concrete floor is most often promised to last 20 years.

If it’s well maintained and sealed when it’s supposed to, some speak of a lifetime. Personally, I have no experience with that, but when you think about how long can concrete last it’s quite possible.

In that sense, in a room that has water use like a laundry room or kitchen, it might make sense to waterproof the slab properly. Some waterproofing can also last from 20 years to a half-century, depending on the material used.

Most bathroom waterproofing systems talk about 10 years guarantee. You can draw some rough outlines from this kind of information.

It will also depend a lot on how much space sees use. When it’s used a lot, maintenance is the key to long life.

Sealing polished concrete floors will prolong its age

Waterproofing polished concrete

So how can we waterproof polished concrete? The surface itself is a little water-resistant after polishing and a densifier has been used to the surface. If it’s sealed well, it’s even more resistant.

Still, it’s only resistant against spills and such, and depending on how the house is built, the edges of the concrete might not be resistant to water. If a water pipe breaks or some other accident with water happens, water might get in the structures from the edges of the slab.

It always finds a way.

Polished concrete sealer

As stated before, concrete densifiers can and should be used on polished concrete floor surfaces. It will stop dusting, make the surface harder and fill the concrete pores.

When the pores on the surface are filled, it’s harder for moisture and dirt to enter them. For normal everyday use, it’s enough.

When you’re sealing polished concrete floors, you will add more to that protective layer. Just remember when you’re shopping for a polished concrete sealer that you need to explain to the sellers what kind of room it’s used in.

Depending on if it’s a water-based sealer or solvent-based, they will have different qualities and looks.

You can also think about a burnished concrete sealer, which is done a little bit differently. A high rpm burnisher is used to spread the topical coating. It will heat and melt to provide some extra protection and provides a high gloss surface for the polished concrete.

If you want to maintain the shine, you can try buffing polished concrete floors when it starts to get dim. Or just burnish again.

The problem with sealers is that if and when it cracks, the water can get through the cracks to the concrete. For that, we might need a stronger solution,

How to waterproof polished concrete

Now to the interesting part. I guess we could say that concrete densifiers, sealers, etc. can give us enough practical waterproof for normal use, but what about real waterproof.

The kind of that can handle water pipe that starts to spray water or sudden rise of water on the floor from drainage and such accidents. I personally used this method on my garage that has a water drain.

The problem was that whenever the sewer stopped draining, it could fill the floor to the floors if no one wouldn’t notice. I wanted to keep it as a concrete surface so I did the following and poured another slab on top.

Step 1: Install puddle flange on the garage concrete floor drain. If you don’t have a floor drain, you can ignore this step.

You can install it on top of the slab, but it might not look that good with polished concrete. I installed it on the old garage floor level. You can read more about how to install it in the linked article.

Step 2: Waterproof the edges of the floor with waterproofing corner tape or whatever is recommended with the waterproof you choose. It’s meant to reinforce the corners so if there is a wall moving and such, it won’t crack and not provide protection from water anymore.

There are self-adhesive tapes on the market, I usually use ones that are not. I use waterproof to attach them to the wall and the floor. Half and half.

Now here it’s good to remember that if you’re raising the concrete floor, you should add at least 2 inches to the height when you put waterproof on the walls. You want it to reach a good height so it will provide protection if water is rising.

Step 3: Once the corners have cured, It’s time to do the floor and I’d do a second coating on the corners and walls as well. For them to be thick as it’s the weak point.

It’s important to follow the waterproof system manufacturer info with curing times and such. If they have a method to do corners, use those, etc. These are built to work together so why not use them.

Also, search local info about what is recommended under the slab in a situation like this. Not every product can handle it I would guess.

Step 4: After the waterproof has cured, you can pour the slab on top of it. Use the method you like the most to do it.

Remember to float it well so that there is “cream” on top to polish it. If you don’t want the exposed aggregates to look.

Remember that it takes 28 days to cure before you start polishing it. Also, remember that if you want it to reach maximum strength, you need to water it a little if you water cure.

Step 5: After the concrete has cured, it’s time for grinding and polishing. There were guides linked at the beginning of the article.

Step 6: Once you have the ground concrete floor at your hand and you have polished it, nothing stops you from using sealer or some other means like burnishing on it or using floor polish for concrete floors. It will provide some extra protection and help your concrete to last longer.


You should know now how to waterproof polished concrete floor in two ways. Both have their own use and I’d not go through with the later method if there is no potential water damage risk.

Pretty much floors that have equipment for handling the water heating and such, laundry rooms and other rooms that have the potential for water damage.

I know many of these aren’t done usually, but if you have a chance to make some changes it could be one way to go. Or if you’re planning to DIY.

I know I sleep better with my garage more waterproof now, I don’t have to stress the sewer overflowing there that much. I’m a little more sensitive to water damage as I’ve seen early in my career how easily it travels through a building with multiple floors.

It finds a way in the structures and can come out of surprising places. For that reason, I try to watch my back with the previously mentioned rooms.

Also, if you’re interested in polished concrete floor finishes, there is still acid staining that could be done on the floor. It changes the color by the chemical reaction so it could be polished in theory.

If you’re looking for alternatives for traditional reflective polish or the exposed aggregates.