Help With Bluestone Staining

eekie34

I recently installed a bluestone patio on an elevated slab of concrete. After about one week, I started to notice some efflorescence which disappated after a few weeks. All around the joints stayed damped, but what is making it look bad is some sort of water stain looking leftover around the perimeter of most of the stones. It looks like water wicking and a halo around the stones. I assume this may be mineral deposits as well? any suggest how to clean or get rid of them?

genecarp

hi, welcome to the site

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ameliapearn

Do you have a photo?

eekie34

Not off hand. The joints were struck concave, and when it rains, the joints are always the last to dry out, and the moisture is wicking from the joints into the edgers of the stone and it continues to travel thru the stone. when it dries out, it leaves what i think is a hard water stain around the edge of the stone. Looks great wet, but not so much with this staining.

artisanstone

Check out this site. http://www.pavingexpert.com/cgi-bin/ib3/ikonboard.cgi
There is discussion there about this problem, commonly called "picture framing".

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Bill Baddorf
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eekie34

any cleaners or solutions to this problem that anybody knows of? I am eventaully going to install a roof over, but I want it to look goos.

Tscarborough

Get it clean and dry and seal it and it should solve the problem.

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CJKarl

Were the joints clean to begin with. How wet was your mortar when you jointed them off?

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eekie34

joints were clean, and used a dry pointing mix that had enought water to be able to ball the stuff up. Wont a sealer trap in any moisture coming up thru the slab?

Tscarborough

Not if you use the proper one. Something like Prime-A-Pell by Chemprobe or some of ProSoCo's sealers will allow vapor transmission, but not liquid water absorption. I do not recommend Prime-A-Pel for horizontal applications, though. I recommend ProSoCo SiloxanePD:
http://www.prosoco.com/ProductDetail.asp?ID={D113DB5A-0836-4C51-822E-B0006E080476}
for porous stone (I am not familiar with bluestone, but assume it is a sandstone or limestone).

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eekie34

That's what i use to wp the chimney work I do. But how do i get rid of those stains, or will they always stay there? Should I clean it will 600 cleaner first?

Tscarborough

600 is for new construction mortar, not this type of stain. Without looking at it and feeling it, I can't be sure which one will clean it, but my best guess would 101 Lime Solvent.

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eekie34

thanks. i'll try the 101 first

Tscarborough

Better to determine what the stone is and what the stain is, first. What is the stone, and is the stain hard and white, chalky and white, or something else.

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eekie34

the stone is pennsylvania bluestone. the residue was white at first and disappeared. what was left has been desribed as pictureframing on concrete pavers, with a dark like water stain remaining when the patio dries.

Tscarborough

OK, I looked it up. It is most likely a sandstone, which means the SiloxanePD is fine. You will need to determine if the stain is soft and chalky or hard, although I suspect soft. If so, then use something mild like diluted CLR, dry to a 24 hour moisture test and seal.

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CJKarl

Another question eekie34, did you use any bonding agent in the joint mix? Sometimes I've seen joint mortar with bonding agent leave a slight discoloration around the joints.
Almost like it seeped outward from the joint.

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eekie34

whats clr? I have a picture, but i don't know how to attach it to the site. computer novice. it keeps telling me it is too big to upload.

Tscarborough

CLR is a hard water stain remover. It is available at most hardware stores, and probably Homeless Depot and WallofChinamart too.

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custom patios

cleaning may work but your biggest problem is the pointing. it is not recommended to strike concave joints for flat work. the patio's integrity is jeopardized by water infiltraion. you really should grind the joints and repoint them flush. a big pita, but i will work. also what mix ratio did you use for pointing.