Removing Cement from Limestone Flagstones *Photos Added*

[JoceAndChris]

PS I think a stonemason would be able to chip away at sections to remove unevenness and get it fairly smooth - but the cost of that would probably be greater than buying reclaimed flagstones (Plus it isn't generally considered good conservation, I wanted my sharp stairs evened out but was told it was better to leave them be from the point of view of conserving original fabric).

 

[benmc]

I have an idea that may just work.

You say the cement comes off with hammer and chisel but this is slow hard work.

What about one of these in an SDS drill

http://www.screwfix.com/prods/89391/Drill-Bits/Masonry-Chisels/SDS-Plus-Chisels/Armeg-SDS-Plus-Tile-Removing-Chisel

I use this for removing plaster from walls.

Got to be worth a go?

Ben

 

[essexbearhunter]

As is any sanding operation, you need to match the abrasive to the amount of "cut" required. Limestone is relatively soft (though the cement adhering to is won't be). In severely hacked areas put fine sand on a small section of the floor and wet it. Then take a section of Dense Concrete Block whose open structure will harbour the sand, soak it for a couple of minutes and use this to rub the sand over the stone. The coarseness of the block itself soon wears off but adding new sand re-invigorates it.

When this becomes too aggressive use a section of brick as a rubber without sand. I use offcuts of some Otterham stocks quite successfully on old bricks. Keeping the area wet means that the resultant debris turns into a light polishing paste. Due to their smaller size the offcuts of brick (about the size of a small sanding block) allow you to tackle details - using corners to get into hollows that you want smoothed but not removed. Otterhams were a uniformly dense modern stock, a bit harder than re-constituted stone and buff/yellow in colour - probably best to avoid red brick on a limestone floor.

 

[Penners]

We did find a few rat bones

I trust you conserved these as historic fabric.

 

[wolfpaw]

What about this stuff??

X-CRETE IS A CONCRETE DE-BONDING AGENT THAT REVERSES THEMOLECULAR BONDING ACTION OF CEMENT AND TURNS IT BACK INTOA LOOSE MIX OF SAND AND AGGREGATE THAT IS EASILY RINSED AWAY]

http://concretedepot.net/catalog/p6278/X-CRETE/product_info.html

 

[wolfpaw]

I'm not sure this is going to work. :? Removing the cement using a hammer and chisel is doing a lot of damage to the face of the stone (as expected) but I don't think the finished result is going to be anything other than a mess:

 

[Penners]

What about this stuff??

X-CRETE

Never heard of it before, but that certainly looks worth a try. If it really works, there are undoubtedly other forum members who would be interested in it.

 

[wolfpaw]

The reason that I can't turn them over and use the backs is because the backs look like this:

 

[Penners]

Yes, a convincing argument!

 

[benmc]

Try using an old 1" chisel to take the concrete off. It were me I would be trying to take all but the final 1-2mm off then use brick acid to clean the remains off.

Ben

 

[MdB]

I can't imagine that brick acid and limestone are very good bedfellows...

(I've never tried it but I would guess that there would be quite a bit of fizz)