Construction Industry/plaster cracks

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Expert: - 1/8/2007


Question
What are various factors of plaster cracking?How should we come to know whether the particular crack is a serious problem?

Answer
Dear Ahamed,
There are several reasons or causes of plaster cracks.  First though - is it really plaster?  Plaster is not used too much anymore - most interior partitions are covered with a gypsum drywall.  
Assuming your finish is plaster, I would ask some questions:  how old is the building?;  is the sub-structure wood lath, metal lath or gypsum lath?;  how thick is the plaster?;  what is the finish of the plaster? - paint, wallpaper, vinyl fabric, etc.

Again, lets assume the partitions are built with 2 x 4 studs, wood lath and plaster surface.  The plaster is applied in 2 (or sometimes 3) coats.  The 1/2" to 5/8" "brown coat" or plaster base is first applied and then an 1/8" "putty coat" is applied and usually toweled to a smooth finish.  Cracks can appear if the drying period was too short; there is settlement in the structure; there is shrinkage of the studs (plaster is a wet application and the wood absorbs excess water); unusual soil disturbance (road building, etc.); weather conditions (high rainfall, extreme freezing, etc.); and excessive water (water pipe leak, overflowing tub, etc.).
Since plaster is primarily a cosmetic finish, cracks are not generally a serious problem.  It cracks because it is not an "elastic" or "plastic" material.  After drying, plaster is quite rigid.  If the cracks are old and have not changed or increased, it can be assumed that the building probably settled and is no longer a problem.  Sometimes the cracks are just in the "putty finish" and can be patched or spackled easily.  If a "new" crack appears, it could be the result of additional settlement or disturbances as noted above.  Usually there are other conditions that occur that may indicate why the plaster cracked - door jambs out of square, baseboard joints open, etc.  
This was a very general answer.  I hope it was helpful.  

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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.

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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.

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

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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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