By Paul Bianchina
The connection between two pieces of wood seems like a simple thing, but it's something that can actually become quite complex in some instances. This is particularly true with large timbers, such as posts and beams, where heavy loads often require very exacting calculations if that connection is to satisfy the stresses placed upon it by wind, snow, earthquakes and even just the everyday demands of people.
Luckily, anyone building or remodeling a home today will find an incredible selection of specially designed steel connectors to secure and support two or more timbers under virtually any load conditions. Companies such as Simpson Strong-Tie and United Steel Products (USP) offer literally thousands of hangers and connectors that are predesigned and engineered to meet a wide variety of load criteria, and if you still can't find what you need, they'll custom make one for you with just a couple of weeks lead time.
In order to select a connector for a specific application, you need to know three things: the size of the timbers being connected; the location of that connection; and the loads the connection will be subjected to.
Timber Sizes
First and foremost, what is the size of the structural member are you connecting, and what is the size of the member you're connecting it to? Quite often, these two members are of different sizes, and you need to select a connector that will fit each piece correctly.
Some connectors are made for standard sizes of solid sawn lumber. These include common sizes, such as 4x lumber and 6x lumber, as well as built-up combinations of lumber, such as three or four pieces of 2x combined to make up a beam. There is also a very large selection of connectors for standard sizes of engineered lumber, such as glulams, I-joists, laminated veneer lumber (LVL) and parallel strand lumber (PSL).
With the immense popularity of engineered lumber, particularly engineered beams, there are also a wide variety of hangers that will joint solid lumber to engineered lumber. If, for example, you wanted to put a 5 ¼-inch glulam beam on top of a 5 ½-inch wide solid lumber post, there is a connector that will fit both of them snugly.
Connection Locations and Loads
Next, you need to know where the connection will occur and then choose the proper connector. You may be attaching a beam on top of a post as described above; attaching one beam into the side of another, perhaps at an angle; connecting a beam into the side or on top of a concrete wall; or having a large hip rafter attach directly over the corner of a wall. The combinations are virtually endless.
Finally, there is the matter of what loads the connection will be subjected to. These might be specified on your plans by an engineer or an architect, or they may be specifically listed in the building codes. There are also regional differences to consider. One area might have very high earthquake standards, called seismic loads, while another might have much greater concerns over what effect high winds will have on the structure, either side to side (lateral loads) or up from below (uplift loads).
Depending on the type of connector and the location of the connection within the structure, the connector may have ratings for seismic, uplift, lateral, download, shear or other types of loads, or even combinations of them.
To avoid a lot of confusion, your best bet is to simply browse through a timber connector catalog. These well-illustrated catalogs show not only the connectors themselves, but also common combinations and installation locations. Charts associated with each hanger show the available size combinations and also any specific load ratings that might have been engineered for.
Timber connectors are available at home centers and lumber yards. Many of the more common sizes are available in stock, and anything listed in the catalogs can be ordered for you within just a couple of days. Your dealer or your local building department can assist you with the proper selection for specific uses.
. Questions of a Do It Yourself nature should be submitted to our "