Best way to clean and seal limestone hearth before use?

There's a product I used to seal some stone sections for my stone mantle. It's made by "Tile Guard" and called "Enhance & Seal". It darkens the rock and seals it. Best to do a section that isn't visable first to see the results.

http://www.tile-guard.com/Product-Information/Enhance-and-Seal-Quart

Looks like it would be a great substrate for a very nice ceramic tile hearth.

I used something called that to seal my concrete patio last year. It was around $150 for a 5 gal pail.

stejus said:

There's a product I used to seal some stone sections for my stone mantle. It's made by "Tile Guard" and called "Enhance & Seal". It darkens the rock and seals it. Best to do a section that isn't visible first to see the results.

http://www.tile-guard.com/Product-Information/Enhance-and-Seal-Quart

Click to expand...

jcims....sorry not to have posted this sooner.

I too have a limestone hearth, and I understand how you'd have some initial misgivings. I had those too, but I've come to accept that I might have been overly worried.

My stone is acid washed, which has a bit more texture.....and more micro pores for soot and ash to lodge. I told myself that I would not seal it the first season, and see how it went. I'm well into the second season, and I'm still on the fence, but I'm thinking I won't seal it.

My first concern is that the heat is going to cook any sealant I put on it, possibly outgassing or yellowing the finish. I plan to coat a stone sample with a couple of different coatings first, put them under the stove, and see what happens. Haven't gotten around to that yet though. If anyone has actually done this to a limestone slab, I'd love to get their opinions on whether they are happy with it, or not.

Initially, you're going to stress over every soot mark you get on it. It is just part of the process of accumulating a patina. Scrub it with mild soap and water if it really bugs you, and that will even out the dark spots and give a nice burnish to the stone. It will darken somewhat, but like I said, I don't find that unattractive. If you ever want to get it back to shiny new, a little phosphoric acid (grout haze remover) will do it toot-sweet. That will also take off that cardboard stain, BTW.

Limestone is most vulnerable to is scrapes and gouges... don't drop a fireplace tool on it and you'll be good.

My advice? Live with it some, accept it for what it is, and you may decide that sealing is not necessary.

That's a very light looking limestone. Around here it usually comes in darker shades.

Whatever you do, a little bit will probably go a long way. Limestone is a fairly soft rock. It falls between 3 and 4 on the hardness scale (1-10) depending on what type of limestone it is. Its a carbonate (basic) so it also reacts with acids, which is why various acids are used to etch/clean it. I think some kind of polishing//burnishing would look really nice.

Glad to help Jcims. Too, don't go overboard with the acid.....check what the dilution is and work in smal quantities. You can actually bleach the stone to the point where you'll have as noticeable a spot as you had with the stain! Your stone does look somewhat lighter than mine, so that might not be too big a concern.

I agree with homebrewz that a polished finish would be more durable and easier to keep clean in general. I opted for the rougher finish because I thought it would look "warmer", and I think it does.