Remove Powdery White Mineral Deposits from Walls
LESLIE: Mary in Alaska, welcome to The Money Pit. What can we do for you today?
MARY: Hi. I have a sun room which is 25 years old. It sits on concrete block…
MARY: … which is six courses from the footing. The outside was sealed and insulated. There are two courses above ground and the outside has cedar siding and the inside is painted.
MARY: About three or four years ago I start noticing a white powder and a sometimes moisture …
MARY: … and it’s gotten worse over time.
TOM: Alright, the problem is called efflorescence and what’s …
LESLIE: And it’s easily fixed.
TOM: Easily fixed. What you have is moisture that’s getting into the block area and then that water is evaporating into the interior house space but it’s leaving its mineral salt deposit behind. So this is really a two-step process.
First of all, inside this comes off with a vinegar solution. It’ll just melt it right away.
LESLIE: White vinegar and water.
TOM: Exactly. Get yourself a gallon of white vinegar and mix it up with some water; spray it and it’ll come right off.
MARY: Mm-hmm, and you may need to rinse it a little bit with water just to get the scent away but the white vinegar makes it go away lickety-split.
TOM: Otherwise it’ll smell like a salad.
And then outside the house you want to take a look at your drainage conditions, Mary, because I suspect that something is not quite right with the drainage; so you’re …
LESLIE: Well, I imagine there’s a lot of snow that sits against the house. (chuckles)
TOM: Yeah, I mean snow that’s melting near that foundation or gutters that are clogged or downspouts that are directed right near that corner; all of those things could add an excessive amount of water to that particular space.
MARY: OK. It is the area where the snow comes off the roof.
TOM: Yeah, well that could do it.
TOM: Make sure the soil slopes away, too, because even if you have snow melt you want the water to run away from that wall. It’s definitely a drainage problem, that source, and it doesn’t sound too serious. So get those two things under control. The efflorescence is basically a clean-up job but outside try to work on those sources of moisture and keep it as far away from the house as possible.
MARY: I can do that.
TOM: You can.
MARY: (chuckling) Yes, thank you so much.
TOM: You’re welcome, Mary. Thanks so much for calling us at 888-MONEY-PIT.