There are many times when building an addition, deck or other project requires the use of steel Joist or beam hangers but how do you know when to use them and what is the best way to install them.
Here we will look at a couple applications for steel and explain the proper install procedures.
When you are hanging a porch or deck off of the side of your home the attachment point is different then inside your home. If you were building a floor on the internal side of your house the first floor joists would rest against the sill plate 2×4 which is attached to the top of your foundation wall. In this situation the weight of the floor no matter where you are standing in the room is transferred through the joist and onto the foundation wall. Other then nailing so things don’t fall apart no real load is put on the fasteners.
When you attach to your ledger board on the outside of the home the weight of the deck is passed through the joist and into the ledger board. The fasteners carry the load of the lumber and the people that are standing on the deck along with any furniture or other items. Nails just are not enough to support this load alone and when you factor in the possibility of wood decay or normal shrinkage and swelling as humidity and water caused the wood to change size you put some serious stress on a couple nails that are holding you three, ten or 18 feet in the air depending where your deck is located and which level of the home it serves.
To add strength in this area you should always use a Joist Hanger to attach your deck to your home. Hangers come in sizes to match the size of the joist from 6″ to 12″ and should be attached with special hardened joist hanger nails only. Never use a common or galvanized nail on a joist hanger they are too weak and will rust or sheer under the weight of the people or items on the deck.
There are also double and triple hangers to attach bonded joists. They are made of heaver metal and won’t bend as easy as a single hanger.
When attaching the hanger find the location of your joist then mark the outside edge of where one side of the hanger will be attached. Nail the hanger to the ledger board and then place your joist in the hanger. Wrap the other side of the hanger tight against the joist and nail EVERY hole in the hanger with a hardened joist hanger nail. There will probably be about 10 to 12 nail holes and don’t leave any empty.
Beam Hangers or Saddle Hangers are often used inside the home to support beams around stairway openings. Your architect should give you the information about the proper hanger to use for your beams and joists. Attach all of the wood to the hanger by nailing every hole with a nail. Saddle hangers usually run over top of a beam running down the center of a room to support joists on each side. Place the hanger over the beam and joists can be hung from each side of the beam. This is a good way to insure that the load of the joists is transferred properly into the beam because along with side load there is also top load on the beam.
Along with steal hangers you will see steel clips for attaching roof trusses to the tops of your walls and a number of other steel parts that can be used in earth quake and storm prone areas. Usually these items will be specified by an architect or engineer. When ever attaching one of these items you should always nail every hole, this can not be stressed strongly enough. Many contractors skip holes feeling if it is attached that is fine but these products are designed to be attached properly or they will fail. If you are going to do a half way job you might as well just stick a piece of bubble gum under your connections, grab a beer and take the next bus out of town because there will be a call or if its your home you will be calling an ambulance when a deck party ends up in disaster.
Well that’s pretty much what you need to know about steel hangers. When a load isn’t supported by a beam, wall or foundation you need to use one. No amount of nails will be strong enough to hold a joist to a wall whether its 3 feet or 30 feet off the ground.
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