White stuff on chimney stones


  #1  
Old 03-12-22, 01:48 PM
D
Member
Thread Starter
Join Date: Oct 2006
Location: United States
Posts: 106
Received 1 Vote on 1 Post
Unhappy White stuff on chimney stones

We had our chimney covered in stone about years ago and now on many there is a white residue ona bunch of them. It can be removed with a wire brush but the brushing is scratching the stone so if I continue I would need to scratch all the stones so they would be uniform but not all of them have the white on them...
Is there a product that removes this lime looking stuff? It is getting worse and I want to keep this stuff from spreading. Thanks for your advice!

White spots on some of the chimney stones
 

Popular Reply

 
03-12-22, 01:59 PM
XSleeper's Avatar
XSleeper
XSleeper is online now
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 29,252
Received 1,528 Votes on 1,372 Posts
My guess would be that it's efflorescense, which is a salt deposit that forms from evaporation. You should NOT use a steel brush if it's scratching the stone... only use a softer plastic or natural bristle brush. A hot water/ vinegar solution with maybe a drop of dish soap would be a mild way to clean and remove it.

Since you are getting efflorescense it likely was never sealed, or needs to be resealed. So once its clean and dry, use a silane or siloxane based product such as BASF Masterprotect.

Since efflorescence is aggravated by water evaporation, you might just do a check to ensure no water is getting behind the stone. This might be due to a leak on your cap or excessive moisture from the house, roof, or gas fireplace. Or maybe it's just from the moisture coming from the exhaust of your gas fireplace... and sealing the stone will help. If its not happening on the sides or rear... that would be a clue. I'm assuming you have a cricket behind the chimney.
 
  #2  
Old 03-12-22, 01:59 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 29,252
Received 1,528 Votes on 1,372 Posts
My guess would be that it's efflorescense, which is a salt deposit that forms from evaporation. You should NOT use a steel brush if it's scratching the stone... only use a softer plastic or natural bristle brush. A hot water/ vinegar solution with maybe a drop of dish soap would be a mild way to clean and remove it.

Since you are getting efflorescense it likely was never sealed, or needs to be resealed. So once its clean and dry, use a silane or siloxane based product such as BASF Masterprotect.

Since efflorescence is aggravated by water evaporation, you might just do a check to ensure no water is getting behind the stone. This might be due to a leak on your cap or excessive moisture from the house, roof, or gas fireplace. Or maybe it's just from the moisture coming from the exhaust of your gas fireplace... and sealing the stone will help. If its not happening on the sides or rear... that would be a clue. I'm assuming you have a cricket behind the chimney.
 
drumz, marksr voted this post useful.
  #3  
Old 03-12-22, 02:06 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 70,098
Received 2,957 Votes on 2,668 Posts
That's called Efflorescence

It's the white substance caused by natural occurring salts found in gravel, soil, cement, water and sand. These salts can then travel in water to the surface of your natural stone leaving behind the crystalline deposits.

Pretty normal occurrence. Will require continuous cleaning. There are many products like CLR that can be used. If you google "efflorescence" many different cleaners are shown.
 
  #4  
Old 03-12-22, 03:51 PM
D
Member
Thread Starter
Join Date: Oct 2006
Location: United States
Posts: 106
Received 1 Vote on 1 Post
It is only on the surface where the exhaust is so I bet you nailed that! I have a message in to the mason that did it since I plan on using him again we have a good relationship. I'm pretty sure he didn't seal it but that is what i will do once it stops raining here (PDX, LOL).
Thanks for the cleaning solution too!
 
  #5  
Old 03-12-22, 03:58 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 70,098
Received 2,957 Votes on 2,668 Posts
Be sure to stop back when you have the problem resolved as others will be reading this thread for help.
 
drumz voted this post useful.
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: