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How to Install Joist Hangers

If you install them properly, joist hangers will keep your decks and floors strong as wood dries, twists, shrinks and ages. We'll show you a four-step method for installing joist hangers that will ensure that your floor or deck stays flat and strong. So the next time you hold a square dance or weight-lifting contest on your deck, you'll rest easier knowing you used joist hangers and installed them the right way.

By the DIY experts of The Family Handyman Magazine

  • COMPLEXITY
  • Complexity Super Simple!
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    Easy if you can handle a hammer; the simple technique is essential for anyone who builds a deck.

How to Install Joist Hangers

If you install them properly, joist hangers will keep your decks and floors strong as wood dries, twists, shrinks and ages. We'll show you a four-step method for installing joist hangers that will ensure that your floor or deck stays flat and strong. So the next time you hold a square dance or weight-lifting contest on your deck, you'll rest easier knowing you used joist hangers and installed them the right way.

By the DIY experts of The Family Handyman Magazine

Select the best hanger for the job

Selecting the correct joist hangers and hanging (or “setting”) them is pretty straightforward. We'll show you a four-step method for installing joist hangers that will ensure that your floor or deck stays flat and strong—and meets the requirements of your building inspector and the joist hanger manufacturer.

Joist hangers come in many sizes to support different dimensional sizes of lumber and I-joists. The hangers you'll find at home centers typically have a galvanized coating and will work indoors and out. Most homeowners will use the common face-mounting type (Fig. A), but specialized hangers are available for unusual situations, such as building in a corrosive salt-air environment or joists that run at an angle.

The performance specifications for each type of hanger are carefully engineered and tested to meet the approval of local building codes. For the performance they deliver and their installation speed, joist hangers are a bargain. Joist hangers are sold according to the size of joists or beams they fit and their load capacity. Home centers and lumberyards typically stock the most common hangers and can order the oddball types and sizes. They also distribute simple and informative brochures that tell you which hanger to buy for which use (like for building a small deck). For bigger projects, pick up a free joist hanger product catalog that lists each manufacturer's hanger types and their uses and load ratings. These catalogs list phone hotlines for engineering help. Manufacturers won't design your project for you, but they'll answer technical questions about specific joist hangers.

Install hangers right—the first time

When I worked construction, I would have lively discussions with carpenters who stubbornly held onto myths about proper joist hanger installation. Avoid installation mistakes by following the techniques shown in Photos 1 - 5:

  • Install the largest hanger that fits the lumber. Never use a 2x6 hanger on a 2x10 joist. Avoid disaster by spending a couple of bucks more for the correct joist hanger.
  • Fill all the holes in each joist hanger with the properly designated size nail. After you've hung 12 hangers on a wall ledger and your arm has turned to rubber, avoid the temptation to save your body by leaving some nail holes in each hanger unfilled.
  • Don't reuse joist hangers, and don't modify them by cutting them shorter or bending their outside flanges (such as around the edge of the wall ledger and nailing into its end grain). Installing reused or modified joist hangers reduces their load capacity. Nailing into end grain will lessen the nail's holding power by one-third.

Nails do matter. Using 3-1/2 in. long 16d nails to secure a hanger to a wall ledger gives you added strength. The long nails bite into the framing members behind the ledger for maximum holding power.

To obtain the full load-bearing capacity of a joist hanger, install the length and size of nail specified by the hanger manufacturer. For interior framing, that means using only the thicker 10d, 12d or 16d common nails (rather than skinnier sinker nails) to fasten a joist hanger's face flange to wall ledgers, headers and beams. Outdoors use 16d double-dipped galvanized nails (or stainless steel when called for) for installing hangers. It's true that hot-dipped galvanized box nails aren't as thick as common nails, but they are the acknowledged choice for outdoor work.

Indoors or out, for standard-type single joist hangers, use only 1-1/2 in. joist hanger nails for nailing into the side of the joist (Photo 5); for double hangers, use 8d or 10d nails. For double shear single hangers (Photo 4), fasten the hanger to the joist(s) with longer 8d or 10d nails. This type of hanger requires fewer but longer nails for the side flanges. The nails penetrate into the wall ledger and therefore offer both better joist load capacity than standard-duty hangers and more protection against uplift forces caused by wind. The manufacturers agree: Never use galvanized deck screws or drywall screws to install joist hangers. Those screws don't have the shank size and toughness to support joist loads.

Inverted double hanger

Special Inverted Flange Hanger

Use inverted flange single or double joist hangers to install joists at the very end of a ledger board. To avoid splitting the outside edge of the wall ledger, predrill the holes for the 16d galvanized nails.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

    • Hammer

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

    • Joist hangers
    • 16d galvanized nails
    • 10d galvanized nails
    • 1-1/2-in. galvanized joist hanger nails

Comments from DIY Community Members

Share what's on your mind and see what other DIYers are thinking about.

1 - 4 of 4 comments
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June 21, 4:44 PM [GMT -5]

To pjdan,
You don't have to nail in the boards but I just had to redo a floor because the previous owners did not nail them in and over time there was some spreading of the walls that caused the joists to pull out of hangers. what a mess.
As for your dad being a little reckless, my uncles and dad all seem to do ok with less fingers after using shortcuts. Of course heavy drinking always helps the numb the pain on the way to the hospital. good luck.
ekeith

October 30, 7:19 PM [GMT -5]

Apparently my city doesn't require the joists to be nailed into the joist hangers. floating in the hangers is perfectly acceptable. My father in-law is building a deck and drilled pilot holes for all his 1 1/5 in 5p nails so that he wouldn't split the ledger before nailing the joist hangers. I would like comments on this as I argued with him about this and now he thinks I'm an idiot since the inspector passed everything with perfect scores.

I'd like to add that the frame is nailed together such that a 1/4 inch of the nails are left un-nailed, ie not fully hammered home. Also he tried cutting a half inch of the width of a 8' board tonight by using the circular saw like a router, ie sliding the saw sideways, perpendicular to the blade to shave off the amount he wanted, rather than ripping it on a table saw or ripping it with the circular saw. His think was that it was far too dangerous. Spent an hour doing this.

Please give me advice before he cuts off more than just a finger.

December 14, 11:24 PM [GMT -5]

Excellent article. A pneumatic nailer can be used instead of a hammer, following instructions for use. As a novice I've discovered traditional hammer nailing won't be a talent I'll be mastering, so I'm looking into the palm nailers. Also, though it may not belong per se in the article, it should be noted that a joist end needs to be within 1/8" of the header, to meet Simpson's specs, along with being fully seated in the hanger and plumb within some tolerance.

lvs

August 24, 7:22 AM [GMT -5]

I liked the article. The photos and accompanying instructions made it very clear what to do in most situations.

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