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This article describes deck safety, deck railing requirements, guard railing construction and building codes, and critical safe-construction details for deck and porch rails, guardrails, and exterior stair guard railings and handrails.

This article includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons. Also see our review of that book.

© Copyright 2012 InspectAPedia.com, Daniel Friedman, Steve Bliss, Wiley & Sons, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

Guide to Building Safe Deck, Porch Railings

This scary guardrail is rotted, poorly fastened (note the nails have pulled away to left of the sagging gate), and the open balusters are a child hazard. Readers should see Railings on Stairways for railing specifications and building code requirements, see STAIRS & RAILINGS for details about the inspection and documentation of unsafe or defective steps, stairs, and railings and see Balusters & Railing Enclosures for additional examples of stair and railing designs and problems..

Deck Railing & Guard railing Code Requirements

Our photos (above) show an attractive railing with horizontal cables intended to permit a nice view of the Brooklyn NY skyline. We also demonstrate how easily the cables can be separated as well as how attractive this guard railing is to children.

As detailed in Best Practices Guide to Residential Construction: The International Residential Code (IRC) requires a minimum 36-inch-high guardrail for all decks, balconies, or screened enclosures more than 30 inches off the ground. For child safety, the balusters or other decorative infill must be spaced less than 4 inches apart (a 4-inch-diameter ball should not pass between the balusters).

Deck Railing Strength Requirements

The railing must be strong enough to resist horizontal loads from people leaning on it. The IRC requires that the railing be able to resist a 200-pound concentrated load applied along the top in any direction, while some local codes still in effect specify a smaller load of 20 pounds per linear foot. After an above-ground swimming pool was removed, the owners continued to use the deck in our photo (left). Deer netting was installed across the open edge of the deck - and it worked fine until someone fell thorough it. The torn remains of the deer netting can be seen on the left side of this photograph. Continuing from from Best Practices Guide to Residential Construction: Under the IRC, the infill or balusters must resist a concentrated horizontal load of 50 pounds applied to a square foot area. The baluster requirement is easily met with standard fastening techniques, but meeting the IRC guardrail requirement is difficult without adding steel hardware. The majority of residential decks, which rely on notched posts lag-screwed into the band joist, do not meet the 200-pound requirement.

Post Connections for Deck or Porch Railings

Posts that run continuously from footings to railings (photo at left) are the strongest, but these are often not practical. (The stair and balcony shown had some other safety problems however.) More commonly, the posts are attached to the rim joist or beam, preferably with through-bolts (see Figure 4-14 below) While 4x4 railing posts are often notched where they connect to the beam, this creates a weak point in the post that will not meet the load requirements. Another problem is that the rim joist needs to be reinforced to keep it from rotating when a strong force is applied to the railing. This can be achieved with lag bolts, steel strapping, or steel connectors tying the rim joist to the abutting joists. On sides where the rim joist runs parallel to the joists, solid blocking should be lagged in place to keep the rim joist from rotating. Additional steel connectors may also be required. Posts should be no more than 6 to 8 feet apart, depending on local codes.

Wood Deck or Porch Railings

The top rail for a guardrail can be a 2x6 either flat (photo at left) or on edge. Use the longest pieces you can find—a continuous railing is best. However for a hand railing on stairs, both flat and vertical 2x lumber are unsafe and violate good stair railing design because they cannot be grasped during a fall.

Our photo above (above right) shows a stair railing that could not be reliably grasped on a stairway where a fall, serious injury, and subsequent litigation occurred. The hand is of the website editor. How to Secure Deck or Porch Rail Balusters: As detailed in Best Practices Guide to Residential Construction and in the figure at left: Balusters can be nailed or screwed directly to the rim joist or attached to a bottom rail. Use either one screw or two spiral-shank nails top and bottom on each baluster. If you use a flat rail on top, it is best to slope or chamfer the top surface to shed water.

Manufactured Deck or Porch Railings

-- Adapted with permission from Best Practices Guide to Residential Construction.

Also see DECK COLLAPSE Case Study (collapse of a new code-approved deck) and DECK FLASHING LEAKS, ROT Case Study for an example of an older deck with rot and collapse due to improper construction and missing building flashing.

Question: can seating serve as a protective safety railing at decks, porches, or outdoors near a high retaining wall?

Subject: 30" railing: If there is a seat wall and a planter between an upper level terrace and a retaining wall with a height greater than 30”, can the railing be eliminated? Please see attached sketch. - M.B.

Reply: OPINION about using seating as a safety barrier on decks, porches, or outdoor surfaces near retaining walls

I have certainly seen a number of high decks (not quite your case) that had continuous seating at the perimeter and no other railings. I expect that ultimately the building code compliance inspector will decide the issue locally.

A concern might be that even though the seating can prevent someone from stumbling and falling off of the raised area, it would not stop a child from climbing right over - unless there were seat backs were high enough and made of vertical balusters rather than the typical horizontal materials.

Taking a look at your sketch (above left), as drawn, the same concept seems to apply: you may have protection against an adult trip and fall over the retaining wall provided by some space (say six feet) between the "seat wall" and the "planter wall" (a retaining wall). But this design does not provide child safety protection nor protection for someone walking in or working in that inner space (having stepped over the seat wall).

If this area is residential occupied outdoor space, I would be surprised if a building code inspection would accept the design you show: the "seat wall" is just 18" high, easily climbed over by a child; there is no safety railing at the planter wall above the dropoff - or are you planning to install a tall, impenetrable solid-growth hedge in the space where you show a shrub? That might be an acceptable alternative.

Our photo of a high retaining wall without a guard railing (left) illustrates an approach using dense shrubbery as a safety barrier at a property in New York State.

Typical building codes including local code interpretations that address the question of need for safety railings near high retaining walls give some latitude to the local building inspector. Examples:

"(B) Safety Railings. Safety railings may be required for any retaining wall two and one-half (2.5) feet or higher. The decision to require safety railing shall be based on specific site conditions, potential pedestrian and public access to the retaining wall, and applicable building codes." - City of Bella Vista, AR subdivision code.

Retaining walls more than 1220 mm high are required to have safety cable railing installed as required by Cal-OSHA regulations, Title 8, Section 1621, as well as the Department's Highway Design Manual Section 210.5. - California DOT DHR - SAFETY ALERT MEMO 03-08

For outdoor double-retaining walls outdoors, the lower retaining wall is 48" in height, the space between the retaining walls is four feet or more, and the top of the wall is 24" high. - Glen Cove, New York

Also see Codes for Stairs where we provide additional detail on railing requirements for stairs, landings, balconies, etc.

Questions & Answers regarding this article

Questions & Answers about deck, porch guard railings & building codes

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Technical Reviewers & References

• InspectAPedia.com^® - Daniel Friedman - Publisher & Editor.
• Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
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DECK & PORCH CONSTRUCTION
Deck Construction Best Practices
  Deck Beams & Girders
  Deck Piers & Posts
  Deck & Porch Connections: Ledger Boards
  Deck Framing Tables, Spans
  Deck Flashing at Building
  DECK FLOOR & STEP CUPPING
  Deck Board Gaps, Spacing Guide
  Deck & Porch Steps or Stairs
  Deck & Porch Railings
  Deck & Porch Products, Manufacturers
  Fasteners, Nails, Screws, Hidden, for Decks
  Fasteners, Structural for Decks
  Finishes, Coatings, Stains for Decks
  Porch Construction & Porch Screening
  Preservative-Treated Framing Lumber
  Rooftop Deck Construction
  Rot-Resistant Deck Lumber & Flooring
  Synthetic Deck Lumber: Composite, Plastic, Vinyl
DECK COLLAPSE Case Study
DECK FINISHES COATINGS PRESERVATIVES
DECK FLASHING LEAKS, ROT Case Study
DECKS, ROOFTOP CONSTRUCTION

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
• Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
• [2] §3209. Standard Guardrails. provides description of how guard rails should be constructed. Web search 09/02/2011,original source: www.dir.ca.gov/title8/3209.html
• [3] "Retaining Walls, When is a Building Permit Required?" City of Folsom CA, web search 09/02/2011, original source: www.folsom.ca.us/civica/filebank/blobdload.asp?BlobID=2580
• Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
• Manual for the Inspection of Residential Wood Decks and Balconies, by Cheryl Anderson, Frank Woeste (Forest Products Society), & Joseph Loferski, October 2003, ISBN-13: 978-1892529343, $39.00 at Amazon.com or at the InspectAPediaBookstore
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