Does the Code Restrict Creativity?
Diana Hanson makes a passionate plea for deck builders to get involved in the code development process (Letters, November 2011) and I agree; getting involved gives you a peek behind the curtain and a better understanding of the issues. But I don't find the assertions she makes to be true - "What is in the code now already restricts what the consumer can have built," and "For the law abiding, it means less creativity and more conventional designs." I have not found any code provision that has limited what I design or my clients want. It could be that my designs are uninspired or clients undemanding, so I'm wondering what specific code provisions Diana and other deck builders have bumped up against?
East Greenwich, R.I.
Diana Hanson replies:
You summed up in two sentences what I and others have been working to change. Many, maybe most, builders just don't see that their livelihood is being threatened by code and the code process.
For example, the code now instructs what materials may be used (Acceptance Criteria and Material Data Sheets) and how and where they must be fastened (2012 IRC Figure R507.2.1(1) Placement of Lag Screws and Bolts in Ledgers, Figure R507.2.1(2) Placement of Lag Screws and Bolts in Band Joists). As a result, builders are pushed to choose products and methods that will meet the path of least resistance during the permitting and ultimate inspection of the deck. Never mind that there is more than one way to construct a strong and safe deck.
I am certainly not saying there is no need for codes relating to decks. What I am saying is that the current process is messy, and that the size and restrictiveness of the code does not equal the safety benefit attained. Left alone, code will continue to increase in size, and further hinder the deck builder's ability to remain a deck builder.
Cable Railing Tips
I liked Mark Ellis' article about cable a lot. I prefer the Feeney wire as well. I would like to add that Feeney sells a little device that allows you to disengage the quick connector, which is normally a one-way street. That comes in handy when you put the connector on the wrong cable.
Ellis recommends that the cable be cut after the quick connector is put in place and tightened. I go back first to the terminal and tighten the cable with a wrench before cutting the cable. This can save you a lot of walking back and forth, especially on long runs.
Also make sure you order "wood" terminals. However, if your first post at the top or bottom of a stair is the beginning of a cable, then the "wood" terminal doesn't work. You want the 3 1/2-inch "metal" terminal.
I order the cable after the railing posts are set and come back to pop the cable in. That's a little inconvenient, but bulletproof. I have many times ordered the cable according to the plans only to find the clients wanted modifications, or that things need to be moved a little, and the cable came up short.
Calvert County, Md.
Railing Post Strength
In your commentary on page 14 of the November 2011 issue, you mention that a 500-pound test load for rail posts is not universally accepted within the code community. I have also heard similar confusion from folks who believe that factors of safety are only involved with testing assemblies, and not engineered assemblies. My reply has been that when you are engineering an assembly to resist a 200-pound allowable load, factors of safety are already built into the design values for the wood (per the NDS), and the fasteners used (per the NDS), and into any connectors used (per a combination of the NDS, IBC, and other standards). For example, the allowable load for the DTT2Z tension tie is based on a factor of safety of 3.0, and the allowable load for our SDS wood screws is based on a factor of safety of 5.0.
So there are factors of safety involved regardless of which approach is used - the testing approach applies a factor of safety to the target load, and the engineered approach applies a factor of safety to the resistance. Either way, the resistance must equal or exceed the load.