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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.
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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 HANDRAILS & HANDRAILINGS 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
[Click to enlarge any image]
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. 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
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 RailingsPosts 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.
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.
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.
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.
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A complete guide to building decks, porches, & exterior stairs can be found at Related Topics above. Key articles include:
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