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Robert Lamoureux: Mystery of the ‘fluffy white snow’ is solved

Your Home Improvements

Posted: January 29, 2010 10:00 p.m.
Updated: January 30, 2010 4:55 a.m.
We have designed a limited edition, custom made, full color The Signal/Your Home Improvements T-shirt that we will send to you, with our compliments, if we answer your question in our column. Thank you, Robert Lamoureux

Hi Robert,

What is the “snow” in my garage? It seems every time it rains, and if there’s any water that gets into the garage, a fluffy white “snow” appears on the floor. After last week’s rain, it was all over and rather thick. With the past two days being warmer, I’ve opened the garage up and swept it out, but I’m curious as to what this is and why it happens every rainy season. I’ve lived in this house for 19 years and it has always occurred. Thanks for your response. I enjoy reading your column every week.
Marianne D.

Hi Marianne,
That fluffy stuff you’re seeing is called efflorescence. It’s commonly found on concrete slabs, brick and tiles — wherever Portland cement is present either in the concrete or grout.  

Rainwater, which contains mineral deposits, evaporates leaving salts on the surface. Water will seep into the slab or grout, both of which are porous, even if just a fraction of an inch, and dissolve the salts in the Portland cement. These salts are then carried up to the surface during evaporation and dry leaving the white residue. The more minerals in the rainwater, and the more salts that are dissolved and deposited, the more efflorescence you will have.  

Some salts can change chemical structure during the efflorescence. These leave residue and stains that require cleansers containing “proprietary chemicals,” but most of the time a firm brush or wash and a stiff broom is all you will need.  

A homemade cleanser made from 1 part muriatic acid to 12 parts water can be used to remove heavier deposits. Make sure you first saturate the areas with water before applying and remember to be careful when working with acid.  

Some good, common sense steps to follow are always wear protective clothing, gloves and eyewear — every time. Also, whenever you dilute, remember to add the acid to water. Don’t add water to the acid because it could possibly erupt and spray on you; and muriatic acid is real acid. It can burn.  

Be careful to avoid breathing the fumes when opening the bottle or after you start working with the acid, even if it is diluted. The vapors are hazardous. You need plenty of ventilation.  Another “don’t” is never open an old, half filled bottle of muriatic acid.

Chlorine gas, which can be fatal, can evaporate from the acid and fill the bottle. If you have a bottle like this around your garage, it should be taken to a hazardous waste handler for disposal.

Hello Robert,
I recently returned home from vacation and discovered I do not have any hot water in the master bath shower of my condo. I have hot water everywhere else, but not in the shower. I would be very interested in learning what could cause something like this to happen. They sent the handy man but he does not know what is wrong. It can’t be the hot water heater, which is my responsibility, because I do have hot water everywhere else, just not in that one shower. Any information you would like to give would be greatly appreciated. Sincerely,
Robin D.

Hi Robin,

It sounds like a bad mix-it valve. It’s not allowing the hot water to mix with the cold.
Now, that does not necessarily mean that your mix-it valve is bad, just that there is a bad valve somewhere in your building. Do you know if any of your neighbors are having problems? We once worked on a property with the same condition. One person’s bad mix-it valve knocked out the hot water to half of the building’s bathrooms.
The first step would be to contact your property manager and have them schedule a plumber for an inspection. If your valve is working properly, he will have to check all of the other units in your building until the bad valve is found. This could take some time so be patient.  Arrangements will have to be made with all of the homeowners for their own inspections.

Hello Mr. Lamoureux,
I enjoy your column. Last week during the rains, I called a plumber out because of a sump pump problem. He suggested that I install a GFI to protect the pump. The price sounded reasonable but I’ve never heard of a pump being on a GFI and I don’t know if it’s a good idea or not? Do you have any thoughts? Thank you,
Manny D.

Hi Manny,

No, it’s not a good idea. The pump is mechanical, usually in a protected vault being accessed by professionals and is not exposed to public tampering or view. A pump is something that you do not want to fail. If it does, that usually translates into a flood.

Temperature and humidity conditions inside pump vaults can sometimes fool a GFI into thinking there is a current problem and it will shut down. Sometimes just a bit of dampness on the plug will cause it to trip. So no, I would not recommend putting a sump pump on a GFI.

The ground fault interrupter is designed to trip on as little as a 4 or 5 milliamp difference.  There are two coils that measure current traveling from the hot to the neutral. The slightest variance in that current will cause it to trip in about 10 milliseconds. They say that’s about as fast as two honey bee wing flaps.  

Hi Robert,
I wrote in about six months ago about our telephone entry system that got hit by a moving truck.  You recommended replacing it with a Door King and it works like a charm. Thank you very much. I don’t have a question but found something in the paper I thought you might find interesting.  

It was published in The Daily Telegraph, London, England and states “Copper Pipes Could Cause Heart Disease and Alzheimer’s.”

The article says that British scientists are warning people of the dangers of copper pipes because the metal builds up in their bodies over a long period of time and cause health problems, including diabetes, because the body can’t process the metal.

The concerns are apparently greater for people over 50, whom they recommend avoid vitamins and minerals that contain copper and iron. Thank you again,
Jacque B.  

Hi Jacque,
Thank you. If anyone is interested in reading more on this, the study, “Risks of Copper and Iron Toxicity during Ageing in Humans” was published in the Dec. 7 edition of the American Chemical Society’s Chemical Research in Toxicology Journal.  

Robert Lamoureux has 25 years of experience as a general contractor, with separate licenses in electrical and plumbing contracting. He owns IMS Construction Inc. in Valencia. His opinions are his own and not necessarily those of The Signal. Opinions expressed in this column are not meant to replace the recommendations of a qualified contractor, after that contractor has made a thorough visual inspection. Send your questions to


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