NADRA Code Update: What Happens in Vegas…

By Glenn Mathewson, NADRA Technical Advisor

…doesn’t stay in Vegas, at least not when it’s about deck code!  Here’s a recap of what to expect in your 2021 International Residential Code from the ICC Public Comment Hearing that occurred in Las Vegas last week.  This information is as fresh as it gets, because NADRA members don’t chase behind future codes, they are part of their creation.

Proposals that did not receive any public comment disputing the committee decision at the first hearing in May are lumped together in a “consensus vote” and these are as good as done.  Here are the proposals the committee approved and will be in the 2021 code.

  • RB187-19:  The organization of footing depth and frost protection provisions have been modified for better comprehension.  Frost protection for decks, previously in the foundation chapter, are now located alongside other deck provisions in the deck section 507.  An added bonus for the free market is a new method for frost protection: “Other approved method of frost protection”.  This will help new innovations that provide protection equivalent to digging a deep hole to have a better chance of being evaluated and approved for use.
  • RB188-19:  A minor change in wording makes it clear that a multi-ply beam must be fastened “together”.
  • RB189-19:  A minor change in wording clarifies that allowable beam cantilevers beyond an end post are based on the actual adjacent span of the beam, not the allowable span.
  • RB190-19:  Many don’t realize that the maximum allowable beam spans, based on the joist spans they carry, are actually sized assuming the joists are cantilevered beyond the beam by their maximum allowable distance.  When not cantilevering joists past a beam, this left beams significantly oversized.  A new modification footnote is now added to the beam span table to allow adjustments based on various percentages of joist cantilever and zero cantilever.  No longer will a beam span be limited based on loads that don’t exist.  This is a huge win for prescriptive deck designs to be closer to the actual design and not a “one-size-fits-all approach”.
  • RB191-19:  With the increase of deck designs and patterns in the industry, many decks are built with decking supported by only two joists and having only one span.  However, decking is not tested or evaluated for performance in this manner, manufactured or wood.  Technically speaking, they are not allowed to be installed in that manner without alternative approval, such as from an engineer.  To support decking designs with validated spans for “single span decking” the maximum joist spacing for wood decking table has been expanded.  5/4-inch wood decking is now provided single span limits of 12 inches for perpendicular installations and 8 inches for diagonal.  Those may appear as new limitations in deck construction, but they are actually new allowances.  What has been being done was never actually supported by the code.  Now it is.  It’s important to note that for manufactured decking, this change can’t be done in the IRC.  The testing standard must be changed.

Three of our proposals were turned down at the committee hearing, and we wrote public comments to give them a second chance.  Another one that was approved received an outside comment and thus needed reconsideration.  The results from the membership vote at the final hearings last week are not the final votes.  Governmental members will still have time after the hearings to make an online vote.  This can change the outcome, but here’s how those proposals currently stand.

  • RB46-19:  Guards and handrails are like peanut butter and jelly.  Just because they can be in the same sandwich, doesn’t mean they are the same thing.  Both are required to resist a 200 lb. concentrated load in “any direction”.  While handrails are meant for someone to purposefully brace themselves while ascending or descending obstacles, like stairs and ramps, guards are only meant to barricade an accidental fall over the edge of the deck.  This proposal changed the loading direction for guards to be only outward and downward and argued that guards don’t need to resist an inward or upward load of that magnitude.  The committee turned this down at the last hearing and said it was the decision of the American Society of Civil Engineers.  The ICC membership at the hearing last week disagreed, and through their professional experience in analyzing guards in backyards across this county, decided to make the decision.  The IRC has now broken away from the singular power of the ASCE to allow a wider diversity of professionals to develop residential codes.  There is value here far beyond this one proposal.  Much like rallying NADRA involvement in development of deck codes, no single group of professionals should be making any rules in our private homes.  That is the beauty of the transparent ICC development process.  Though the final vote is given only to governmental members (a single group of professionals), they are the only group free from financial interest or professional gain from the results.
  • RB184:  This was our biggest proposal and with modifications, the ICC membership voted it with a 98% approval!  That’s a great way to start the online voting and a good sign this will make it in the future code.  Here are some bullets of what this large proposal offers.
  • Design tables are increased for 50, 60, and 70 psf snow load regions, making the code more useful to more builders in the country and reducing the need for specific engineering.
    • The absolute minimum diameter footing was reduced from an excessive 14-inch diameter to as low as 8-inch diameter when supporting deck areas up to 5 square feet.  (consider a small stair landing with four footings/piers)
    • The post sizing table was expanded and based on the actual loads the post is carrying.  No longer are there single limits for post height based only on the heaviest possible loading.  Like with beams and joists cantilevers, previously mentioned, it’s no longer “one-size-fits-all”.
    • The joist span tables have been revised so that maximum cantilevers of joists are no longer based on the maximum allowable span of joists, but by their actual span.  Like other modifications, this allows design limits to be based on the actual deck design.
  • RB185-19:  This proposal was approved by the committee in the first hearing but received a public comment that fixed an oversight in the first proposal.  It was then approved by the membership.  New provisions prohibiting the notching of 4×4 guard posts at the connection point were included alongside language requiring guard post connection to tie into the overall framing of the deck, and not just a single side joist.  Without limiting guard design and construction methods and without providing any specific graphics, this proposal will support better guard construction without a loss in architectural freedom.
  • RB301-19:  Of all our proposals and all our testimony to other proposals, this was the only one that we didn’t win.  Turned down at the committee hearings, this proposal would have provided specific details for guard post connections in an appendix chapter.  An appendix chapter is optional and must be individually adopted by a government.  Though our industry fears pictures in the code (think…lateral load anchor), the compromise with others who don’t share this fear was to put them in an appendix.  The details provided engineered methods of resisting a 200 lb. load on a single post using either metal hardware or only commodity fasteners.  Through much debate and mutual compromise, the Deck Code Coalition was still unable to provide unified testimony in support of this proposal.  The membership did not approve it.

Modifications to these proposals can no longer be made in this cycle, as all that is left is the final online vote by the governmental members. 

By the end of this year, the 2021 IRC will be decided.

To help NADRA continue our work in the code arena, please consider contributing to our code fundraising initiative. Click here to learn more and to support our efforts.

NADRA CODE UPDATE

August 14th, 2019

By: Glenn Mathewson

Proposal RB190 – Table R507.5

Through the efforts of NADRA.org and other organizations and professionals, the 2015 IRC revealed the first deck beam-sizing table (Table R507.5) to ever be included in a US model code.  It provides maximum spans of simple deck beams based on different loading, species, profiles, and number of plies of common lumber.  It was a welcome addition for building departments that have long struggled to approve deck designs without requiring an engineer and without having to develop their own span tables, as many had done.  The American Wood Council (AWC) created their popular document, DCA6, to help alleviate this problem and provide pre-engineered design tables.  These tables would become the 2015 provisions, and still today the AWC provides the engineering for most of the new deck structural provisions.  For contractors working in regions not utilizing the DCA6, the new tables came as a little shock.  In comparing the beams spans that have been acceptable, the new IRC tables cut them down dramatically.  Why?

Creating a pre-engineered design table is not necessarily simple, specifically for beams.  To provide a maximum allowable beam span, the load the beam is supporting has to be known.  In its most simple form, a beam supports joists of the same length and carries half that length.  A ledger, presumably, is carrying the other half.  Those same joists, however, could cantilever beyond the beam, and the beam would support the entire load of the cantilever.  This is just one design variable of many.  A beam could be at an angle and support a non-uniform load along its length, or it could be supporting joists spanning from both sides.  Currently none of those variables are provided in the code.

Why did many allowable beam spans suddenly reduce with the new code?  The table is calculated on the assumption that every beam is supporting maximum-cantilevered joists.  In many cases, joists can cantilever beyond the beam up to 1/4 their span, and that’s a lot of added load…load that is being designed for every time, whether there or not.  Consider a deck with a 12 ft. joist span and no cantilever.  The beam is actually carrying 6 feet of joist, but the code is sizing it as if it’s carrying 9 ft., because it’s assuming the maximum allowable 3 ft. joist cantilever is there.  If you did cantilever the joist the maximum distance, the table is accurate.  If you didn’t, your beam spans are unnecessarily restricted…significantly.  Okay—Let’s fix that!

The NADRA proposal RB190 adds a footnote to the beam span table with a set of modifiers.  The modifiers allow you to alter the input “joist span” in the beam span table based on different percentages of joist cantilever from zero to one-fourth.  Included are cantilevers of 1/12, 1/10, 1/8, 1/6, and the maximum 1/4 of the joist span.  Currently, a (2) 2×10 southern pine beam supporting a 12 ft. joist span is restricted 7 ft. – 4 in., REGARDLESS of whether the joists cantilever or not.  With RB190’s modifiers, if the joists don’t cantilever, the 12 ft. span can be multiplied by .66 to yield an equivalent span of 8 ft.  Using this value in the table results in an accurate maximum beam span of 9 ft.  That’s no small margin from the current 7 ft. – 4 inch maximum!  There is no reason not to allow beams to be sized for their actual loads, and possibly reduce some costs or visually obstructive posts from our neighbors’ backyards.

Proposal RB190 was prompted by NADRA, developed with the help of the Deck Code Coalition, and engineered by the American Wood Council.  It is solid engineering in a solid concept.  It was approved at the Committee Action Hearings with no opposition.  There is good reason to believe it will make it through the last part of the ICC code development process, the Final Action Hearing.

Please support proposal RB190 and let’s maintain an appropriate balance between safety, design freedom, and affordability. 

Please contact NADRA for any questions or concerns regarding this proposal.  We welcome your conversation. You can send an email to Info@NADRA.org

NADRA Code Update

July 3rd, 2019

By: Glenn Mathewson

To finish a marathon, you’ve got to push through the last mile.  Such is the same with developing a new edition of the International Residential Code.  Thousands of people are currently running a marathon toward the 2021 IRC, and though they are halfway through, there’s no telling who (or who’s proposals) will make it to the finish line.  While it’s too soon to start cheering, it’s not to soon to feel confident and strong, and that’s how the NADRA and Deck Code Coalition proposals are looking.

With the publishing of the final report from the Committee Action Hearings, the public can not only see the results of the hearing, but also a summary of the comments made by the committee.  There are three result categories, but since those aren’t “final” results, the comments should be the focus.  The committee comments could be looked at as spectators cheering on or booing the runners.  They provide direction, encouragement, and suggestions, much like “you got this! Keep going! You’re so close”.  Unfortunately, sometimes the comments can feel more like “you’re never going to make it! Give up now!  You look so tired!”

The race is not over until you pass the finish line, and sometimes people get a second wind.  That’s what the next phase of the code modification process can offer—a second chance.  Regardless of the committee result, every proposal can receive a public comment modification, and if received, the proposal will be heard again at the final hearings, where a final vote will be made…but not really.  The final vote is actually made online a few weeks after the hearing.  In this vote, only governmental ICC members can cast the final thumbs up or thumbs down.   These members could vote down a proposal approved by the committee, and likewise, the members could turn around a proposal disapproved by the committee.

Public comments to the committee results are due July 24th and these will be the catalyst for the next step in the process.  A proposal that does not receive a public comment is almost certain to be finalized as-is in the “bulk vote” where the governmental members vote for the entire package of proposals.  Having not received any disagreement from the public, the assumption is that the committee opinion is good to go.  Here is the part to pay close attention to:

If the committee result for a proposal is not challenged by July 24th, consider it done.  If there is something you don’t like, silence is equivalent to support.

So let me put it this way…  “Speak now or forever hold your peace”.

Okay…that’s not exactly true, but you would have to hold it until the 2024 IRC code development hearings where everything is on the table again.

Thanks to select NADRA members that have financially supported NADRA representation in the code modification process, I am working alongside other professionals in the Deck Code Coaltion and we are preparing public comments.  We are running this marathon until the end.  I hope you are on the sidelines cheering us on.  Here are the results and comments from the Committee Action Hearings that have us in a runner’s high.  You can view all the Group B ICC documents and the live video from the Group B hearing at this link:  https://www.iccsafe.org/products-and-services/i-codes/code-development/

RB184: Disapproved

Committee Reason:  There were multiple corrections expressed in a modification that the committee felt was too extensive. The wording in Section 507.4 is confusing. The committee urges that the corrections should be brought forward in a public comment. The collaborative effort, and inclusion of engineers in the effort, was a positive aspect for this proposal. (Vote: 10-1)

RB185: Approved As Modified

Committee Reason: The modification to Section R507.10.1.2 removed ‘approved’ because this adjective cannot be applied to manufacture’s instructions. The modification to Section to R507.10.2 reworded the two sentences for clarity. The modification to Section R507.10.4 removes ‘approved’ because this would be confusing to the homeowner. The proposal provided good general prescriptive language for guards that will reduce the need for engineering of guards. The committee had several suggestions for better wording that should come forward in a public comment: Add ‘also’ to Section R312.1.4; ‘design’ instead of ‘construction’ in Section 507.10; revise ‘prevent’ to ‘limit’ in Section R507.10.1.1; joists are part of the deck framing, so the language in Section R507.10.1 is confusing. (Vote: 9-2)

RB186: Approved As Modified

Committee Reason: The modification restores rivets and puts in the term ‘glulam’ to be consistent with the term used in ASTM F1667. Adding the Class D is appropriate for this product. (Vote: 11-0)

RB187: Approved As Submitted

Committee Reason: The committee felt that the overall proposal is a good reorganization that add clarity to the code requirements. Item 3 in Section R507.3.3 is an alternative means that is currently allowed in Chapter 1. (Vote: 11-0)

RB188: Approved As Submitted

Committee Reason: This revision will clarify the engineering option for deck beams where fastened together. (Vote: 11-0)

RB189: Approved As Submitted

Committee Reason: This change clarifies the cantilever limitations. (Vote: 11-0)

RB190: Approved As Submitted

Committee Reason: The proposed footnote allows for a design that does not use the full cantilever, which will allow for a more efficient design. If you do not use this option, the table is more conservative. The commentary should include an example. (Vote: 11-0)

RB191: Approved As Submitted

Committee Reason: The revisions add clarification to the code and allows for better design practice for wood decking. (Vote 11-0)