White residue on cement floor

Nov 16, 2003 14 Replies

I have a cement basement floor that has never been sealed or painted. I am getting a white residue from time to time. Bleach does not get rid of it, so I'm figuring that maybe this is a mineral deposit? The basement has high humidity and is musty at times. Ideas?



I was wondering if applying a seal coat would elimate this.



Thanks for any suggestions.



Bob Z


Is that what is called "Efflorescence"; i.e. what happens when excessive moisture leaches lime and other chemical 'salts' out of the cement. Since cement is made with lime (Calcium Hydroxide?), an alkaline, I guess that using bleach (Sodium Hydroxide/Hypochloride or is it Hypochlorite?) wouldn't do anything to 'dissolve' the whitish residue or crust? Is acid ever used? What's that stuff that bricklayers use to clean up lime mortar splashes etc. Perhaps someone with a better grasp than my out of date and poorly remembered High School Chemistry could come to the rescue? High humidity? Wet ground? Poor drainage under basement floor? Rot, allergies to mould, damp insulation etc. Some ventilation might help?

Water is pushing up and effloresing, muriatic acid will remove it . You should run a dehumidifier . I take it you have no drain tile system. You probably have a high water table and it will continue. Paint will only peel till you fix it.

Not likely - a surface coating won't overcome the hydrostatic pressure.

Waterproofing Membranes from Laticrete may help you.

(I remember you)

drylock works great for keeping water out!

Whoa, some correct names are: lye is sodium hydroxide, bleach is sodium hypochlorite, lime is calcium oxide, and slaked lime is wet calcium oxide (calcium hydroxide). All are basic, so to dissolve them you need an acid. Weak hydrochloric acid will dissolve the white stuff.

Improved drainage would probably help, and you might improve your situation if you better manage runoff from your roof (move it away from the house) but if you have poor subsurface drainage you might not be able to do much about it without great expense. Beyond that I'll leave it to the concrete specialists. Ventilation will certainly help in reducing any possible mold problems.

i wonder, is it only seen on the floor slab? do you see anything at the foundation walls? how old is the house? was there work done to increase the basement height by digging down? its going to be hard to find if you have a drain tile or not, and harder to install not to mention big bucks. you have to help minimize the water going to your foundation. start out with the downspouts, make sure they extend out from the wall about

6ft, the further the less water outside your foundation.

"3rd Generation" wrote don't forget the website

formatting link

Hey! I remember both of you! hahahahahahahahahaha!

is Chief, Art or is Art, Chief

if your not sure ...........goby yourself a clue. or I could sell you one real cheap. hahahahahahahahahaha!

want to play "Where's Art"?

admit it.....you miss me!

Search the web for "Efflorescence". You have it.

-Bruce

Wow thanks B. That makes a half dozen in this thread that have ALLREADY said that. For a top-posting imbecile you're originality is exceptional..

"Forrest" wrote in news: snipped-for-privacy@comcast.com:

Not to mention the incorrect usage of "you're."

ahh.. hook line and sinker. stinkbait. always the ticket.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required