White marks on black limestone Indian flags/slabs (for wood burner hearth)??

[Mr. Clueless]

We are having a multi fuel stove installed in February. My mother had a guy install her fire & he laid down the black limestone flags which look superb. Nice deep black.

I have been able to pick through the actual crate of Indian flags but they are ALL marked with this white coating. Some more than others. Every single flag without fail out of every single crate without fail has some of this white marking on it. Some not so much, others lots.

When the flag is wet, you can't see it, but when it dries out, it's clear to see & looks terrible.

I know you can 'seal' them (colour enhance?) but does this get rid of the marking? They're not scratches/gouges.


I asked a builder today but i'm not sold by his answer....

He said that you simply cannot get rid of the marks. They need to 'weather out' (& being inside they wont do that).
He said you need to get flags out of the crate that have NO marks at all (as i said - not possible). Seal them, point them, then seal them again (i told him they were for a hearth).

I'm not sold by this.

The flags...

Then today i tried out the water thing to show to you what i mean....

The next pics are of the SAME flag. Dry, wet with & without flash....

What i want to avoid is these flags being put down & having all this horrible stuff showing through once the fire is installed. If i need new flags then so be it.

 

[geraldthehamster]

Try some sealer on one of them. You'll probably find it has a similar effect on the appearance as wetting it.

 

[Mr. Clueless]

Assuming it does (& removes the white 'stuff'), what would be the best process here?

Sealing before laying?

I would've thought that this would surely have to be the process because once the fire is on, it's going to be a royal PITA sealing it.

But i don't want to just assume.

 

[geraldthehamster]

Lay, seal, grout, seal again, fit stove.

 

[CortinaV8]

If you are actually intending on using the woodburner, after a few months it will look similar with all the ash that inevitably drops onto it.

I know mine does.

 

[Mr. Clueless]

My mothers was sealed & hers actually looks fine tbh. I don't think much ash gets on there either. Maybe she puts paper down when cleaning or something.

3 flags won't need much sealer. Hopefully you can pick up small containers & not just big ones.

And brand names worth a shout or is it a case of when you've seen one you've seen them all?

I heard of a customer at our place having bad experience with one sealer reacting with his black flags though which is why I ask.

 

[theprinceofdarkness]

Its a surface effect, you know those lovely black granite work surfaces, they will all be slate grey in 1000 years, while all your white marks will have turned black. As for myself, I had a limestone fire surround made, as delivered it was all one colour, very very light cream. Eight years on its now about 3% black markings which are little shells and the base colour is just lighter then butter. You will have to be careful about not dragging or dropping any pokers/shovels/brushes on the surface. As for mine, is just grubby, a patina , I think its called But I know an hours rubbing down with wet and dry will make it snow white again and featureless for another eight years.
Frank

 

[Mr. Clueless]

I was looking for sealers or colour enhancers.

But of a minefield, with such varying prices.

I believe it's a colour enhancer i'm wanting & not necessarily a 'sealer'? I want the deep black to show.

What colour enhancers should i really be looking at here?