Enhance Your Outdoor Space with Heavy Stainless Deck Solutions
Recently, we took a look at a specific pergola made from Cedar Wood framing. It’s a particularly delicate assembly of materials because the wood used for a lot of the framing is relatively thin and on a tight spacing but the overall aesthetic looks very impressive. And although this is made from thin wood, the deck is built in a very durable way, both from a mounting perspective and also from a resistance to external elements.
And even though the framing materials used are intended to be lightweight, the overall connection is built in a strong and durable manner as well. Thick stainless brackets have been used to mount the base of the structure to a large concrete planter. The upper portions of the pergola are assembled with half inch bolts that pass through, drilled, and bored, through the elements, to connect one to the next.
The picture below shows a double mounting plate which is bolted back to the concrete structure and connects the base of the four posts that run together at each centered column area.
One might think that a lighter weight attachment might be sufficient to support the weight and load and sway bracing required for this pergola, but in this case they’ve used a 3/8 inch thick plate with quarter inch splines routed into each of the four posts. The next picture below shows the thickness of these plates.
This particular plate is made with 304 stainless steel. if this plate was instead made with a regular ferrous metal, without particular preventative treatment, the plate, mounted against a concrete base, might encourage accelerated oxidation which would lead to deterioration and failure.
Stainless steel like this has roughly 18% chromium, and roughly 8% nickel. The chromium and the nickel are mixed or smelted together with the iron in the alloying process. The chromium blends with the other ingredients in the steel to form a transparent oxide layer (Cr2O3) when it is exposed to oxygen, such as in these plates and bolts. The chromium creates a self-healing protective barrier, whereas the steel alone without the chromium and nickel would rust to the point that it would deteriorate back to dust and dirt, in the form of iron oxide. That’s is how stainless avoids oxidation or rusting.
However, if you work closely with a variety of different types of stainless steel, you may have noticed that even some materials such as fasteners, washers, nuts and hardware can actually still oxidize to a degree. It takes time and iterative exposures to high amounts of moisture, but over time even some stainless steels can rust.
If you look at the next picture below, you can see where the plate mounts back to the concrete. But you can also see how each of these plates connect to the post, the center of the post is routed with a dado type cut into the cedar wood post and from that location a stainless steel plate, welded to the ledger plate is inserted into the post. The picture below shows the back of the post.
A dado is a particular type of groove or channel cut into wood that runs across the grain of the lumber. Unlike a simple groove that might be cut along the length of a board, a dado is intended to receive and secure another piece of wood or, in this case, a metal plate, creating a nestled joint.
Dados are used in woodworking and carpentry because they provide more surface area for gluing or mechanical fastening, and they help align and stabilize connecting pieces. The depth of a dado typically ranges from 1/4 to 1/3 of the material thickness, providing holding power while maintaining the strength of the wood. In traditional woodworking, dados are often used for shelf fabrication where shelf ends fit into dados cut into the vertical sides, but in this application, the dado serves as a specifically fitted slot for the stainless steel plate, ensuring proper alignment and additional structural stability for the plate connection.
The next picture shows the sides of the post, each of those sides has a bolt and nut run through the post, side to side which also runs through the middle of the plate which holds the whole assembly together. Washers are also used in combination with the nuts to expand the surface area of the pressure applied from tensioning or torsioning the nut and bolt.
The whole assembly that we are looking at in the pictures above shows the base of the structure and the manner in which it is mounted to the substructure.
In another upcoming article, we’re going to take a closer look at the actual fastener bolts and examine some of the differences between the options available for bolts and screw / driven fasteners. Different types of threads, nuts, shafts and sizing, are all factors which can make a big difference in the amount of resistance to weather and deterioration and in the structural capacity.
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
