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Expert: - 8/23/2007


Question
We had our weeping tile done and waterproofing (leaky basement). They backfilled with the dirt they dug out, and tamped it. 10 months later we had a stone porch built on top. Part of the porch sunk in several feet. The builder of the porch says the waterproofers made an error and left holes in the backfill and that they should have used gravel not dirt. They will re-build porch but say it would happen again if the situation below is not repaired first. I am afraid the waterproofers will say it is not their issue. They gave a 20 year guarantee ... not sure if this would apply to such and issue. It is quite a sink hole area. Please help...thank you so much. Please let me know is it industry standard to back fill with dirt? Jennifer

Answer
Jennifer,
The correct way to provide drainage to a basement is:
after pouring the footing and walls, lay a perforated pipe at the footing level in a bed of rock or gravel, with gravel on top plus a layer of filter fabric.  Then the excavation can be backfilled with the same soil that was excavated - assuming it was not all roots or muck - in what are called "lifts" of 1 foot which is then compacted thoroughly.  Then the 2nd lift, etc., and continue to compact as the soil is added.  Settlement will occur but not to the degree you describe.  Usually the excavation for a basement is about 3 feet beyond the basement wall.  When your porch was built, did the contractor anchor the new footings into the existing basement wall?  This is done for the express purpose of avoiding settlement.  The original contractor of your basement is the responsible party.  The waterproofer was either an employee or sub-contractor.  If your home is still under warranty (usually one year) the general contractor is responsible.  Also, did you have settlement prior to the porch being built?  In my state (Florida) I must provide density tests to the building inspector for soil below a footing.  Perhaps the porch contractor should have tested the soil to insure the proper density or compaction.

I hope this has been 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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