Cleaning a concrete wall before painting


  #1  
Old 04-28-11, 11:19 AM
T
Member
Thread Starter
Join Date: Mar 2009
Location: New York
Posts: 35
Upvotes: 0
Received 0 Upvotes on 0 Posts
Cleaning a concrete wall before painting

I want to paint my concrete basement walls but before I do I will need to clean them. There are some spots on the wall that has a white residue on it. This was from my down spouts dumping all the rain water next to the house. I now routed the down spouts 15' away from the house. So I shouldn't have that problem anymore. Does anyone know the best way or product to use? Someone mentioned muriatic acid, but I have read that it is extremely corrosive. Also, I have a six month old baby in the house so I don't want anything that will stink up the house with bad fumes. Any suggestions?
 
  #2  
Old 04-28-11, 01:57 PM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 27,979
Received 2,229 Upvotes on 1,988 Posts
The muratic acid right from the jug is very corrosive and dangerous so yes, you do need to be very careful when handling it. For cleaning the walls you will dilute it to a concentration that is much safer to handle. I would not have the baby in the room when you are working and absolutely keep him/her away from the bottle of straight acid at all times.

I can't really say muratic acid has much of a smell, and what smell there is does not linger. Surprisingly it's a pretty simple and natural product that is easily neutralized. I find it much less offensive than Fabreeze or air fresheners. The straight acid from the jug has fumes, not really an odor

Is your basement finished? I hope you can use a pressure washer or garden hose to wash down the walls. I put the diluted solution in a pump sprayer and spray the walls. It will fizz and usually turns a yellowish color. If the efflorescence is heavy you can also brush the help mechanically remove the minerals. Before the acid solution dries I thoroughly wash it off with a garden hose or pressure washer. The pressure washer is by far the best since it also removes dirt, spider webs and loose mortar blobs...
 
  #3  
Old 04-29-11, 06:49 PM
T
Member
Thread Starter
Join Date: Mar 2009
Location: New York
Posts: 35
Upvotes: 0
Received 0 Upvotes on 0 Posts
The basement isn't finished yet so I can wash down the walls. I'll give the muratic acid a try. Thanks for the info.
 
  #4  
Old 04-30-11, 04:19 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,730
Received 854 Upvotes on 748 Posts
Pressure washing might be more effective but what I usually do when dealing with efflorescence on interior masonry is just to knock most of it off with a wire brush. A little bit of efflorescence shouldn't affect the paint job and you won't have to wait days for the block/concrete to dry. It would be best to prime the walls with drylok before you paint them - most any latex paint will work for the top coat.
 
 

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