Construction Industry/Spotted Concrete

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Expert: - 5/14/2007


Question
My house is one year old. Our concrete driveway, front sidewalk and porch have spots all over them. The spots look like it started to rain, but then stopped and the spots never dried -- like permanent wet marks, in other words. This condition seems to have developed over time, as my wife and I do not recall noticing the effect when we did our walk-through before moving in. I am going to bring this up to our builder's warranty rep when we do our 12-month report, but would like some advance information as to what might have caused this if I can get it. None of the other homes in our subdivision seem to have this condition. Also, the driveway's surface has a lot of small, scattered holes of one-eight to as much as one-half inch in diameter. We have not used any chemicals on the driveway whatsoever. Any thoughts? Your help will be greatly appreciated.

Answer
Dear Earl,
I wish there was a really good solution to your problem.  Concrete has many variables including, amount of water, amount of cement, condition of aggregate, time of pour, temperature at pour, as well as the ability or experience of the mechanic.  The spots are difficult to control.  Try a mild meratic acid wash being sure to rinse thoroughly.  As for the small fissures, the surface was "over trowelled" and the aggregate is brought near the surface.  A change in weather or slight movement of the concrete, or a car moving over the area could cause the concrete to spawl.  
Again, I wished there was a remedy but concrete is not a very forgiving material.  Once it has set-up, it can't be changed.  Removal and re-pouring is the ultimate solution.  A topping or thin layer of concrete is a "bandaide" and will eventually crack and peel off.
Hope this was helpful.

Roger

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Roger Zona

Expertise

I am experienced in all types of construction: residential, industrial and commercial; single family, multi-family, mid-rise and high rise buildings (16 story office building) as well as remodeling, additions and tenant improvements. I can field most any question that relates to general construction. I have consulted with infrastructure (utility) contractors also and have a good general knowledge of underground utility construction for subdivisions and commercial projects.

Experience

After college, I began my career in the construction industry. I chose to become an apprentice Architect and 4 yrs later I opened my own architectural design firm. Six years later I moved to Florida to buy & develop land and build. I became a State of Florida Certified General Contractor and operated my business for 45 years. I built all types of residential and commercial buildings including warehouses, shopping centers, high rise apartments and office buildings and developed sites for other contractors. I retired and became a consultant to the construction industry. I maintain my license and continuing education requirements, operate a small construction company and write a weekly newspaper column for the Palm Beach Post (a Cox publication) with the byline "Ask The Contractor". I am the "technical editor" for a publisher of books that relate to home maintenance.

Organizations
Previously - NAHA Currently - FLCA (Florida Licensed Contractors Assoc.)

Publications
Palm Beach Post newspaper - weekly Q & A column Happy Herald monthly real estate publication - monthly column

Education/Credentials
Michigan State University University of Detroit BS in Engineering

Past/Present Clients
I built a home in Palm Beach for a member of the Pulitzer Family. I was responsible for the completion of a twin hi-rise condominium project for G.E. Credit. I was a partner in the successful development of a P.U.D. (Planned Urban Development) subdivision. I represented the largest home builder from France (Bati Service, S.A.) in the development of a subdivision and the design and construction of the homes.

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