On Metal Connectors
They say that in this world it isn’t WHAT you know, but WHO you know. Well, we aren’t sure we agree with that. However, when it comes to CONNECTIONS we can say with some certainty that “the right connections can make all the difference in the world.” We assume you are aware that we refer specifically to construction connections – not the political kind. If politics was the topic we would be talking about “getting nailed” instead. OK, enough about the government.
If you’re thinking about adding on to your home: a room addition, an out building or a patio cover, then you need to know about metal framing connectors. Metal framing connectors are special metal devices that provide added strength at wood connections where nails alone would not be as sufficient.
Although metal connectors are commonly used throughout the country in wood frame construction, they have a special value in areas where earthquakes, hurricanes and tornadoes are prevalent. Structural integrity is only part of the picture. In patio cover construction, for example, connectors that help attach posts to beams reduce the chance of both from twisting. They do this by simply holding the wood in place as it dries out. One thing about wood, it loves to change shape as it dries out.
Believe it or not, every type of wood connection can be joined with a metal connector of one kind or another. Connectors come in all shapes and sizes and range in thickness from very thin and lightweight, stamped- or punched-sheetmetal units to heavy-gauge forged steel units that weigh more than a large dog. By the way, with metal connectors “bigger” is better.
Connectors can be broken down into two basic categories: hangars and ties. Ties and hangars are both used to create stronger connections, but hangars have the added advantage of holding floor and ceiling framing up where a post or wall support would be impractical. Hangars are used to support the end of a horizontal framing member from its underside. Like when a deck is built onto the back of a house. You know, where the rear wall is used as the support for one end of the deck framing. First, a board is nailed onto the house (it’s called a ledger). Next, joist hangars are nailed onto the ledger. Finally, each deck joist is placed into the pocket of a joist hangar at one end, with the other end placed on a support beam.
When they’re little they call ‘em joist hangars. When they grow up they are referred to as beam hangars. What are you going to be when you grow up son? Well dad, I think I want to be a beam hangar. Oh God!
Nails are great, but a plain vanilla nailed connection can be pulled apart – pretty easily in fact. And although it is true that a connection made with a metal connector can be pulled apart it takes about a gazillion times more force to separate it than a simple nailed connection does. End nailing is where wood connections are most vulnerable and where metal connectors are most important.
If this all sounds too technical maybe we offer some practical reasoning why metal connectors make sense. First, in an earthquake it has been found that the earth’s movement causes the house to be thrown upward from the foundation. By the time the house begins to fall back toward the earth the foundation moves sideways and the house plummets off the foundation and onto the ground. With positive connections between the house and the foundation the house would not leave its concrete support and therefore stand less chance of being thrown off of it.
A similar principal is true with hurricanes. It is important that windows be kept closed in a hurricane. Air pressure traveling through the window and into the home can actually lift the roof right off the house. Keeping windows closed can create negative pressure inside and help to hold the roof in place. But proper nailing and keeping windows closed aren’t enough in many cases. With only nailed connections a roof could be blown clean away. Using metal connectors to attach each roof-framing member to the wall that supports it makes for a more positive connection. And if heavy winds occur there is a better chance that all will stay in place.
It should be noted that special nails are used to install joist hangars. They are called – and very appropriately we might add – joist hangar nails. Since this type of connector is commonly cross-nailed into one and a half-inch thick boards joist hangar nails are just under an inch and a half in length. And that’s a good thing because you don’t have to worry about driving a nail through your finger when you’re installing a joist hangar.
So tell us, now do you agree that it’s a good idea to good connections?