You are here:

Architecture/standard stair tread and riser geometries

Advertisement

Expert: - 1/10/2005


Question
Rich,

I'm considering renovating the stairway to my basement/family room.  The house is a 1950's Cape Cod with inadequate head clearance in this passage way.  Currently the staircase has 11 steps with a tread and rise of 9.5" x 8".  What would be the downside of 10 steps with a tread and rise of 9.5" x 8.8".  Is that too steep?

Thanks,

Jon

Answer
Jon:

Thanks for your question!

Yes, that's a very steep stair, and illegal everywhere.

Tread and riser height is regulated by code.  In many jurisdictions, the minimum tread length is 9" and the maximum riser height is 8 1/4".  The national model codes however have adopted stricter stair geometry requirements and many building authorities are adopting them.  A very common tread/riser relationship is 10"/7 3/4".  Code writers are pushing towards the commercial standard of 11/7.

There are also width, headroom, nosing, railing, and other requirements for a code stair.  Check with your local building department for the proper details.

As an option for a tight area, some jurisdictions allow an "alternating tread stair" which can fit in a very small space.  Again, check your local building department to see if this is allowed.

Stairs are probably the single most dangerous part of any house.  Accidental falls on stairs happen for many reasons (each year about 239,000 or 9% of all stair accidents happen to women in high heels and children) but steep stairs are a leading contributing factor.

Hope this helps!

Richard Taylor, AIA
Richard Taylor Architects, LLC
www.rtastudio.com

Architecture

All Answers

Answers by Expert:

Ask Experts

Volunteer

Richard Taylor, AIA

Expertise

Ask me about all aspects of house, remodeling. , and room addition design and construction. Ask me about historic homes, renovation, and restoration. Ask me about materials and techniques, and about how you can get the best value for your design and construction dollar. Ask me how you can make your home a very special place. I can't, however, answer specific structural engineering questions in this forum - that's something you'll need on-site observation for.

Experience

I own a full-service residential architectural firm, and have been designing custom homes, remodelings, and room additions across the country since 1983. Check us out at Richard Taylor Architects and RTA Plans. I have written and been published extensively on the subject of residential architecture.

Organizations
American Institute of Architects, City of Dublin Architectural Review Board, Vice Chair of City of Dublin Planning and Zoning Commission, American Planning Association, Board Member Historic Dublin Business Association, Past Editor of SPLASH (a software forum), Past Editor of Open Directory Project, Assistant Scoutmaster, Boy Scouts of America

Publications
Business First of Columbus, Suburban New Publications, About.com, Cleveland Plain Dealer, Columbus Dispatch Residential Architect Custom Home Architect Remodeling Architect

Education/Credentials
Bachelor of Environmental Design (Architecture) Miami University 1983
For more about home design, check out my blog at Sense Of Place and join the conversation on our Facebook Page.

Awards and Honors
2010 Dublin Chamber of Commerce Business Person of the Year

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