Sealing might help. I'm not an expert on slate but my sealed slate has only lost material on about five tiles since 2005. What is is cleaned with?

I know that slate is basically a metamorphic rock made up of layers of mud from a billion years ago. The reason it is easy to make in to thin tiles is because of the ability to 'flake' or split into thin pieces.

It looks like your slate is weathering or flaking (part of its natural process as compressed mud layers). I'm going to guess it is time to have it ground and polished (and probably sealed).

This is the beauty of stone flooring - it can be "sanded" (ground down) and repolished...kinda like wood.

A stone flooring professional should be able to come in and grind/polish and seal it for you.

What’s underneath the stone? Are there any water pipes? Has your area been experiencing a larger than usual amount of precipitation recently? What do you clean with? Is the spalling (i.e., flaking) happening everywhere or is it confined to that small area? Don’t seal it until you know what’s going on!

Here’s an article on the subject: Why is my natural stone flaking?

The slate tile is installed over the house's cement slab. There are no water pipes under it. I live on the Texas Gulf Coast, so lots of rain, but nothing standing around the slab. The flaking is happening in the entire room. I've only cleaned it by sweeping, vacuuming and a sponge mop with warm water, sometimes a little soap. I'm not sure about the "sanding" recommendation. Seems that would make the floor flat like regular tile and not preserve the layers of the slate that make it unique. Thanks for everyone's assistance.

Did you get a solution for your flaking slate? i have exactly the same problem. Mine was caused by a saltwater pool. Tried so many sealers. Nothing works. Keeps on lifting. I thinking about a clear epoxy coating over the area. Gonna be very shiny but at least keep the slate look hopefully. I do know that epoxy yellow over time so maybe not the best solution. Has anyone tried epoxy over slate before? or should i try polyurethane rather? Need help here pleas.

No, never got a solution or a reason for what is happening. I just have to vacuum every day to get the pieces of slate contained so it's not dragged through the house. We can find no water coming from beneath the house. Ultimately, I'm going to have to jackhammer it out and replace it with something else. We've sealed the slate on our front porch and small side patio with a glossy finish sealer. It doesn't stay shiny too long, it's so hot here (Houston) it has to be resealed every year to 18 months. Even with many coats of sealer, it absorbs into the slate because it's natural unfinished. Good luck with your problem, hope you can solve it.

Same here. Tried so many different sealers. Nothing worked. Today we coated it with Epoxy coating. This is the last try. Epoxy is very hard, it might work. But we hand sanded all the flakes off. Used a wet mop 5 times to get the dust off. Vacuumed again and then cleaned with a TFC stone cleaner. They applied the first coat Epoxy. It looks good so far. Epoxy lifts extra loose pieces and hardens sandy tile, so far. It is as if it puts a glass coat on top. Gonna be shiney but rather like that than the black flakes and black feet Will let you know in a few days. Still need to do half of it and then second coat. Holding thumbs. Mine is 100sqm area. It's big. After 5 years of struggling with it.

I hope your Epoxy works and looks good for a long while. It's interesting to learn they have a lifespan in the high traffic areas. I have an area rug over part of the room, it's not shedding large pieces as the areas we walk on, but it's powdery underneath the rug. I loved the look of the slate. We didn't install a barrier between the slab and slate when it was installed. I'm wondering if that would have helped? Anyway, I think I'm done with slate and eventually will replace it with something else.

This is our last try. We do have a membrane between the slab and the slate because of the heavy rains in Cape Town and moisture from underneath. We had them dried out for 4 week now after cleaning. It's under a dome roof, no moisture, hoping for the best. If it lasts for 5 years it's good enough. But yes i am also done with slate.

We're dealing with it in a sunroom. This is depressing but I think accurate. Impregnating sealer. https://www.tilecleaning.org/sealing-slate-shower.htm