Fasteners for Structural Ties: Essential Components for Safe and Secure Deck Builds
In the past, here on our blog and website, we looked at a few different examples where other deck builders, here in Washington DC omitted important types of deck connecting fasteners and hardware. These parts are useful and generally required by the building code, to hold decks together in ways that prevent lateral deflection and uplift in heavy winds and storms. Without these ties and mechanical connector to hold the framing elements together, the lifespan is shortened and the framing has a higher likelihood of failure.
These connectors resist racking forces and structural type shifting that’s inherent in subsoil movement and high winds. The problem, though, is that in the Washington DC area, there are many different types of contractors and some of them don’t have full or proper training in how to build decks. Many people might build a deck on the back of their home is a DIY type project (and we encourage DIY projects in general when it is safe and pragmatic). We believe that most people are capable of more than they realize with just a bit of proper helping guidance. However, relatively thorough knowledge base is required to both design and build decks properly.
Here in these pictures, we’re looking at a deck nearby to where we are working, but this is not a deck built by our company. Overall, it’s not as bad as some of the things we normally see done by other contractors, but even here in a case where they’ve installed hurricane clips in the locations and quantity required by the building code, they’ve used the wrong fasteners. They’ve used regular deck screws. These deck screws are good quality, and generally have high resistance to oxidation and corrosion. They also have relatively high tensile strength and resistance to deformation under stress. These particular fasteners are expensive, as well, so the people who installed them didn’t necessarily do it just to save a little bit of money, but this installation still isn’t correct.
Some of the reasons why the framing screws are not as strong come down to shear strength and ductility. These are both similar types of resistive forces, and although similar they’re a little bit different. The shear strength is the nail or screw’s ability to resist lateral force. A nail has higher strength in this type of characteristic than a screw. The ductility is related, but it specifically applies to the fastener’s ability to bend where the screw instead will shear at a lower amount of force.
Another important factor is the pull through resistance. It’s hard to imagine the head of these screws being pulled through the smaller hole in the hurricane clip. These holes are pre-punched or drilled in the hurricane clips and you can see right in the picture below that they are much smaller so it would take a considerable amount of force to pull the head through the free cut hole in the hurricane clip. However, this type of resistance is important, because uplift, compressive, and racking forces can literally twist decks into contortion and rip these connective joints apart. TECO Nails have a stronger amount of resistance to pull through than the framing screws.
And, even with all this talk about the differences between screws and nails, another separate but important requirement of the building code and the usage of these types of clips and TECO Nails is that every single hole has to be used or filled in the critical ranges at the ends of these hurricane clips. You can see here, and several of the instances shown in the pictures above and below, some of the holes in the critical areas have been omitted and have no fasteners installed. That’s a problem and the fasteners would need to be installed to meet the requirements.
We’ve made a pretty clear distinction, in our explanation above between screws versus nails, but it isn’t just that screws are not approved, in some cases screws actually can be approved for the same use as TECO nails in installing these clips and special types of hardware. However, the specific deck screws with bugle heads are not appropriate and should not be used. Those screws are approved and suitable for many cases of framing installation where boards are directly connected to other boards. As well, there are several circumstances where an alternative different type of screw can be used directly in the hurricane clips and other types of structural connectors in lieu of TECO nails. An example of these type of screws in similar configurations or installations is shown below
These images show examples where the staircase stringers have been connected to girders and rim joints at the outer edges of the decks. The stair ledger is connected to the rim joist at the outside edge of the deck.
A combination of different types of connectors have been used here and fastened with approved hex head screws. These screws are specially made for installation of hurricane clips, similar to TECO nails, with higher ratings for ductility, pull through resistance, and shear resistance.
Use a contractor who understands and cares about doing things right. Always, feel free to reach out to us here at Dupont Decks and Patios. We are happy to help with almost all steps of the deck building and design process. A backyard and outdoor space should make a significant, positive impact on both quality of life and home value. We can help with more than just decks, we also build patios, pergolas, ramadas, awnings, gazebos, arbors, and privacy fences.
Let us know about your ideas and talk to us if you have questions about possibilities. We are happy to participate in improving your outdoor space and quality of life! You can call us at (202) 774-9128. You can find us online at https://dupontdeckspatiosdc.com and you can email us there as well at https://dupontdeckspatiosdc.com/contact-us
