How to Replace a Deck Joist Hanger

If your deck gets a lot of foot traffic or if you use salt to combat snow and ice, your joist hangers may begin to wear out over time. These metal brackets hold up the floor joists that support the deck’s surface, and your structure wouldn’t be safe without them.

Luckily, homeowners with moderate DIY skills can easily replace them when they fail. In this guide, we’ll explain how to replace a deck joist hanger with This Old House experts Nathan Gilbert and Tom Silva.

Signs of Joist Hanger Failure

Checking your deck regularly can help you identify potential issues with joist hangers before they become serious problems. Look for:

• Gaps between the joist and the hanger
• Loose or missing fasteners
• Sagging or uneven deck boards
• Visible rust or corrosion on the hangers

In the video above, the homeowner’s problem was obvious: One joist hanger had completely rotted out, and one end of the deck joist had fallen to the ground.

Removing Old Joist Hangers

After you’ve found the problem joist hangers, you have to remove them. This process requires careful attention to avoid damaging the surrounding structure. Here is a list of the tools you’ll likely need to get started:

• Hammer
• Nail puller
• Pry bar
• Reciprocating saw
• Safety glasses
• Work gloves

Once you’ve gathered you’re tools, follow the steps below to remove the old, damaged joist hangers: 

1. Support the joist with a scrap piece of lumber to keep it in place.
2. Inspect the area and identify all fasteners securing the hanger.
3. Use a reciprocating saw to cut through any nails or screws that you’re unable to remove.
4. Pry the hanger away from the ledger board using a pry bar.
5. Remove any remaining fasteners using a nail puller or hammer.
6. Clean the area of any debris or rust to prepare for the new hanger.

Installing New Joist Hangers

Now that you’ve removed the old hanger, it’s time to install the new one. Before you can do that, you have to choose the right hanger, though. Select a joist hanger that matches the size of your joists and is appropriate for your deck’s construction. In the video, Gilbert uses a two-by-eight face-mount galvanized joist hanger, which is suitable for many standard deck configurations.

Also, note the style of the joist hanger you removed. You’ll want to match it with your new one. Common styles include:

• Adjustable hangers: Allow for slight angle adjustments in joist placement
• Double joist hangers: Designed to support two joists side-by-side
• Face-mount hangers: The most common type, attaching to the face of the ledger board or beam
• Top-mount hangers: Used when the top of the joist is flush with the top of the supporting beam

Tools and Materials Needed

Gathering your tools beforehand will make the process more efficient. Collect the following items:

• Drill driver (if using screws)
• Galvanized nails or structural screws
• Hammer or palm nailer
• Level
• New galvanized joist hangers
• Pencil
• Tape measure

Installation Steps

In the video, Gilbert uses a combination of screws and a specialized nailer while installing the new hanger to make the process more efficient. Consider this as you follow the steps below:

1. Position the hanger: Place the new hanger on the ledger board and make sure it’s aligned properly with the joist.
2. Mark fastener locations: Use a pencil to mark where the fasteners will go on the ledger board.
3. Pre-drill holes: Drill holes if you’re using screws to prevent the wood from splitting.
4. Secure the hanger: Attach the hanger to the ledger board using the appropriate fasteners.
5. Fit the joist: Place the joist into the hanger and check that it’s a snug fit.
6. Fasten the joist: Nail or screw through the hanger into the joist per the manufacturer’s specifications.

How to Keep Your Deck Safe Beyond New Joist Hangers

Beyond replacing the joist hangers, there are a few other things you need to do to make sure your deck is safe. Regular deck maintenance includes:

• Checking for rot: Inspect the wood for signs of rot, especially in areas that retain moisture. Rot can weaken your deck over time.
• Monitoring board movement: Observe any movement in the deck boards. If they appear to shift, it might indicate underlying structural issues that need attention.
• Tightening loose fasteners: Fasteners may loosen over time, particularly in high-traffic areas. Regularly check the stability of these connections.

By taking the time to perform regular maintenance, your deck and its components, including the joist hangers, will last long, function properly, and remain safe. We recommend that you apply a water-repellent sealer to protect the wood and reduce moisture exposure, and clean the deck surface and between boards to prevent moisture accumulation.

Consider using joist tape on top of joists to prevent water from seeping into screw holes.

Tips for Preserving Joist Hangers

Corrosion can shorten a joist hangers’ lifespan, but you can take steps to prevent premature failure. Select joist hangers and fasteners with appropriate corrosion resistance for your environment, such as:

• Hot-dip galvanized hangers and nails for general use
• Powder-coated or specially treated hangers for enhanced corrosion resistance
• Stainless steel hangers and fasteners for coastal areas or high-moisture environments

Another thing that takes a toll on deck hardware is salt. If you put salt down when your deck is icy, it can cause your joist hangers to corrode. If you must use salt, rinse the deck thoroughly with water on warmer days so that you remove residue, but consider these alternatives for managing ice on your deck:

• Heated mats: Prevent ice formation in high-traffic areas
• Magnesium chloride: Less corrosive than traditional rock salt
• Sand or kitty litter: Provides traction without melting ice

Our Conclusion

Replacing a deck joist hanger is a manageable DIY project that can improve your deck’s safety and lifespan. By using the right materials and following proper installation techniques your deck will remain sturdy and secure. To make sure your deck holds up for years to come, we recommend you implement preventive measures, such as applying a water-repellent sealer and inspecting your deck for wear and tear.