The Best Tips I’ve Learned to Clean Rough Slate Floors

Inside: My honest first-hand experience with the best way to clean slate floors with a rustic, uneven surface. Plus easy tips and tools to use on this rough stone flooring and proper care to maintain its natural beauty for a long time!

You could say I’m a fan of slate tile floors for the heavily used kitchen and family room area—I’ve had it in my last two houses.

The floors in these highly lived-in rooms take a beating, and this durable stone floor laughs at it. I mean, it’s literally layers of metamorphic rock after all. While a little piece may chip off here and there, it only adds to its rustic charm.

Why else do I like it? Slate adds the right touch of rustic to the room, the natural stone is always timeless, and it’s not slippery when we come in dripping from the swimming pool. It’s not damaged by those standing puddles of pool water that no one cleans up. And its earthy colors hide dog hair, dirt, and dust bunnies.

While I love that I don’t have to babysit it, there is one issue that’s always bothered me. Getting it clean.

Every time I’d mop it, the water was brown. In our previous house, the slate was brand new so I chalked it up to “dust” from cutting the natural stone and that would be gone after a few moppings.

Nope. No matter how many years of mopping the slate in either house the mop water was brown, dirty, yucky. Every. Time.

Because I need to believe my house is clean, I was on a quest to know why. Was this just something I had to deal with in exchange for all of slate’s benefits? Why wasn’t anyone on the internet talking about this being an inherent problem with slate flooring?

I’m sharing here what I found out, and what’s worked best for me in my 20 years of first-hand experience with having a rough slate floor. Plus some of the best cleaning tips and tools I’ve found that have worked for others!

Why does my slate floor never come clean?

As it turns out, it’s not the slate. It is actually dirt. Because this kind of slate’s rough surface is covered in nooks, crannies, and crevices. Every edge holds onto the dirt.

If you look closely at my slate floor tiles, you can see what I’m talking about. This particular tile even has a huge natural cleft to collect dirt:

To make it worse, my slate floor is in high traffic areas, so the dirt accumulation is even greater.

I found in my research that slate tile comes in four different types of surfaces or “faces”.

• Cleft or Natural: Has the most edges and clefts but is the most durable because if any chips happen they look natural
• Tumbled: Still rough but the edges are slightly smoothed
• Honed: Mostly smooth with a slight texture
• Polished: Completely smooth with a shiny finish and not durable at all

As you may have guessed, my slate is the first kind with a cleft or natural face, and that is why I’ve had this cleaning problem whereas not everyone with a slate floor does. If you have slate and you’re wondering why cleaning is such an issue for me, you might have one of the other smoother types. Easier to clean, but a little less durable because the chips on the other kinds will be obvious.

Disclaimer: My cleaning tips and experience in this post are for rough surface, natural, cleft slate tile. Do not try any of these tips if you have slate tiles with a smoother surface, as you may scratch, damage, or make noticeable chips in them.

Deep Cleaning Slate Floors.

So how do you get all the dirt out of the crooks and creases? The best way is the old-fashioned way—scrubbing it out with a deep clean.

1. Clean up the loose dirt and debris.

Before starting the deep clean, first remove any loose dirt. I prefer to use a vacuum cleaner to ensure I’m removing the dirt and not just moving it around. (More about sweeping rough slate below).

2. Scrub the tile and the grout.

To stop the never-ending brown water, you have to strip away all of the dirt that’s built up in the rough parts of the slate.

There’s no magic remover for all this ground in dirt. Both the tile and the grout need a good major scrubbing.

The grout lines between the slate tiles are really what make the floor look dirty. If left without a deep cleaning for years, it often becomes the same dark brown color as the slate.

I’m not going to recommend any cleaning products and tools that will strip the sealer or surface off. If you want to go for this deeper deep clean, there are commercial stripping cleaning solutions for slate and you can rent or buy electric floor scrubbers with rotating scouring pads. Or you can leave stripping the tile, grout, and existing sealants to professionals.

After you’ve deep cleaned, there’s a good chance your floor still won’t look clean because the grout becomes stained over time. See how I fixed mine in the post “The Only Way to Refresh Dirty Tile Grout That Really Works“.

For a good deep clean you’ll need:

Cleaning Solution:

A mild dish soap mixed with warm water (about a 1/4 cup soap to 1 gallon of water). Or buy a specially made pH-neutral slate floor cleaner or stone cleaner. Whatever you choose, don’t use harsh or acidic cleaners (no vinegar, lemon, or bleach) as they may damage the stone.

Bucket(s):

You’ll need at least one bucket. If you’re cleaning by hand in sections, you’ll want one bucket for the cleaning solution and one for clean water.

Mop and/or Clean Rags:

For completely removing the dirt you’ve scrubbed up and the cleaning solution.

Scrubbing Tools:

For small areas, use a scrub brush and scrub by hand in manageable sections. A deck scrub brush is a great tool to have for scrubbing floors!

If you have a big expanse of floor, save some wear and tear on your body and rent or invest in a tool to do some of the scrub work for you. A couple of highly recommended options:

For scrubbing: Ryobi ONE+ 18V Cordless Telescoping Power Scrubber Kit

For steaming: McCulloch MC1275 Heavy-Duty Steam Cleaner (You can also rent a commercial steamer from somewhere like Home Depot)

SH&H Tip: Make sure to completely remove the soapy water or cleaner so there’s no leftover film to attract dirt.

3. Treat Stains.

Slate is a porous stone, so if it’s not properly sealed, it can absorb spills. Grease and oil stains, or red wine are common in the kitchen.

There are a couple of stain removal options you can use with things you probably have around the house:

• Apply 1/4 rubbing alcohol mixed with 4 cups of water and scrub the stain with a soft bristle brush.
• Spray the stained area with a 1:1 ratio of hydrogen peroxide and water, let it sit for 10 minutes, scrub, and rinse.

4. Seal the Tile.

Sealing slate floors is vitally important in keeping them clean and preventing stains. Most tile installers will seal the tile when they finish as part of the job. Looking for a sheen on the tiles is the easiest way to determine if yours has ever been sealed.

If you’re going to the trouble of deep cleaning the slate floor, sealing it or resealing it right after only makes sense, as it’s recommended yearly.

To be totally transparent, I’ve never sealed my slate floor myself and have never re-sealed them either. The sealer on the floor in my current house was a little heavier and more noticeable than I liked when we moved in, so I’ve been able to get by so far because it has a ways to go before it wears off.

But when choosing a sealant, be aware there are different types of sealers for natural stone floors. Test it first on a spare tile if you have one to see the end result you’ll get.

• If you want to maintain the natural look with little change to the color or texture, use an impregnating clear sealer that penetrates down into the stone.
• If you want to enhance the colors and add a shinier finish, go with an enhancing sealer that sits on the surface of the stone.

My personal preference is an impregnating sealer. It adds a slight sheen and brings out some of the color and natural beauty of the slate, but without the dramatic color change and gloss of the enhancing sealers (plus they’re usually water-based, making them easier to work with).

The Best Way to Routine Clean Uneven Stone Floors.

After the dirt has been removed and the slate has been sealed, you have to stay on top of keeping it away with regular cleaning.

Sweeping.

Simple sweeping is an issue on this uneven, rough tile floor. For my marble and wood floors, I like to use a Swiffer. But on the rough slate with holes, edges, and larger grout lines, these smooth cloths were a no-go, snagging on the rough texture, and they didn’t get down into the holes and grout valleys.

In my experience, a vacuum cleaner is the best way to remove the dirt from down in the holes and grout lines. You can also use a broom or dust mop to sweep it out, but it sometimes just moves it from one crevice to another. I like that the vacuum cleaner removes it altogether. Although I don’t do it on my extra rustic slate, it’s recommended by professionals to turn off the vacuum’s beater bar and use the bare floor cleaning setting so it won’t mark up or chip the surface.

Mopping.

Just like with the deep cleaning, you’ll want to use the right cleaning products to do daily mopping. Any mild detergent and water or neutral cleaner for stone will work.

The kind of mop is up to you, but when dealing with this uneven floor, again you’ll want to skip the Swiffer-type pads that are made for smooth tile and floors. I use a basic string mop.

Many swear by a steam mop, and I love the idea for a kitchen for sanitizing. But in my personal experience in the past, the steam mop didn’t glide over the rough tiles easily enough for me. If you have one that does let me know!

Common issues with slate floors.

It seems people either love their slate floors, or they hate them. These are the complaints most often heard:

• Slate can be subject to scratching and chipping. This hard stone floor has a softer side you need to be aware of. To avoid potential damage, don’t use abrasive cleaners or cleaning tools that could scratch the surface. Use furniture pads or slides. The only way I’ve ever scratched mine is when a plastic slider unknowingly broke off of the bottom of a chair leg, exposing the nail that held it in.

SH&H Tip: Camouflage chips that bother you with a little mineral oil.

If you’ve also battled the slate floor that never comes clean, I hope this post has helped you skip some of the frustrations I’ve had. And if you have any other tips that have worked for you in cleaning rough slate, let us know in the comments!

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