Photo of a residential deck construction(C) Daniel Friedman Guide to Safe and Legal Porch & Deck Railing / Guardrail Construction & Codes
Guardrail best practices

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Guardrails Best Practices for Decks & Porches:

This article describes recommended construction practices for 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.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Guide to Building Safe, Legal Deck, Porch Railings

Tall entry stair (C) Daniel Friedman

Discussed here: Deck, porch & retaining wall railing & guard rail construction, materials, designs; How to connect deck guardrail or stair rail posts to the deck structure; Deck & porch railing construction details & structural fasteners; Deck & porch guard railing construction details for safety; Deck & porch railings: code requirements; Railing requirements for decks, porches, exterior stairs.

[Click to enlarge any image] - 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.

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.

Deck Railing & Guard railing Code Requirements

Unsafe railing in New York City (C) Daniel Friedman

[Click to enlarge any image]

Our photos (above and below) 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.

Unsafe railing in New York City (C) Daniel Friedman

See Cable Railings & Guardrails for details about cable type guard rails or "cable railings" such as shown above.

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 (Guardrail) Strength Requirements

Deer Net deck rail (C) Daniel Friedman

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

Railing and stairfall injury lawsuit photo (C) Daniel Friedman)

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 at above had some other safety problems however, including non-graspable 2x6 on-edge handrailings along the stairway and balusters spaced too far apart.

[Click to enlarge any image]

More commonly, the posts are attached to the rim joist or beam, preferably with through-bolts.

Posts should be no more than 6 to 8 feet apart, depending on local codes.

Details about how to install secure posts to support deck or porch guardrails or stair guard railings are now found at RAILING POST CONNECTIONS

Also see GUARDRAIL POST CODES & SPECS where we discuss whether posts are required or not in guardrail construction.

Wood Deck or Porch Railings

Guardrail top (C) Daniel Friedman

The top rail for a guardrail can be a 2x6 either flat (photo above) or on edge. Use the longest pieces you can find—a continuous railing is best.

Guardrail top (C) Daniel Friedman

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.

Wood raiing details (C) J Wiley & Sons Best Construction Practices Steven Bliss

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.

Prefab porch railing (C) J Wiley & Sons Best Construction Practices Steven Bliss

Many types of manufactured railing systems are also available, often from the same companies that provide composite decking products.

Examples include SmartDeck’s post and rail system made from an extruded wood-poly composite and a similar railing made of fiber-reinforced plastic (FRP) from Shakespeare Composites, best known for its FRP fishing rods (see photo at left of a pre-fab or manufactured porch railing system).

An advantage of the prefab systems, in addition to their easy assembly, is that most are engineered to meet the strength requirements of the model codes in the areas where they are marketed (see Deck & Porch Products, Manufacturers)

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

Details for baluster choices and installation are at BALUSTERS, STAIR & RAILING

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

Seat wall as safety railing (C) D Friedman M.H.

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

M.B. please see RETAINING WALL GUARDRAIL CODES for a discussion of retaining walls and guardrail requirements (or absence of them) in building codes & standards. Generally retaining wall guardrails are not addressed in building codes except in some cases where there is a requirement for a guardrail (not plantings) for public spaces where people might be expected to walk along the area close to the retaining wall.

That said, 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.

Retaining wall damage © D Friedman at

Our photo of a high retaining wall without a guard railing (above) 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


Continue reading at GUARDRAIL CONSTRUCTION, DECKS & RAMPS for guardrailing specifications & codes, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see DECK & PORCH GUARDRAILINGS FAQs - questions & answers posted originally at this page

Or see BUILDING CODE DOWNLOADS - free downloadable PDF files of building codes & standards

Or see BALUSTERS, STAIR & RAILING for additional examples of stair and railing designs and problems.


Or see DECK DESIGN & BUILD - home

Or see these

Guardrail / Railing Articles

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