Construction Industry/slope of concrete

Advertisement

Expert: - 8/12/2008


Question
hi i am trying to calculate the percentage of slope for a thirty foot walkway. what formula do you use to figure it out?

Answer
John,

First you must know the high point and the low point.  Lets make some assumptions.

Lets say the high point is 15" above the low point of 0".  Convert the 30' to inches (360") and divide 15 by 360 and the answer is
.041666 percent of the length.  If you keep it in feet, divide 1.25 by 30 and the answer is the same - .041666 pecent.  .041666 times 360" is 15" or .041666 times 30' is 1.24998 feet.

When building a ramp for handicap use in our area, the slope can't exceed 2%.  Using this as a factor - in 30 feet (360") you can raise the high end of the ramp by .6 feet or 7¼".

Now, if you are required to raise a ramp by a factor of degrees, you use a different calculation.

Again, using the 30 ft. distance, assume you are required to ramp no more than 3 degrees, then you divide 3 (degrees) by 90 and the result is .03333 of 360" or 11.9999" (say 12")

Does that make sense?

Hope this was helpful

Roger

Construction Industry

All Answers

Answers by Expert:

Ask Experts

Volunteer

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.

©2012 About.com, a part of The New York Times Company. All rights reserved.