When building decks or floors for different structures there are different ways to attach joists to various structural materials. Joist hangers, though, make it easier and more accurate to attach joists to ledger and rim boards and other support frameworks. If you’re looking for information about joist hangers, we’re here to help!
Joist hangers are easy to install and provide a strong connection between building components and structural support members. There are different hanger designs to suit most building requirements, and several types of metal and thicknesses too. Always use the recommended number of appropriate fasteners to maximize connection strength.
In this guide, we’ll explain what joist hangers are, when they should be used, corrosion concerns, and code compliance. We’ll identify the different types of hangers, sizes, and load capacities. Plus, we’ll discuss installation, fasteners, popular manufacturers, and alternative connection methods to using joist hangers. Our aim is to provide you with a complete practical guide to joist hangers.
- What Is a Joist Hanger?
- When to Use Joist Hangers?
- Are Joist Hangers Required by Code?
- Different Types of Joist Hangers
- Joist Hanger Sizes
- Joist Hangers and Corrosion
- Deck Joist Hangers for Treated Lumber
- Fasteners for Joist Hangers
- How to Install Joist Hangers Correctly
- Joist Hanger Load Capacity
- Popular Joist Hanger Manufacturers
- Alternative to Joist Hangers
What Is a Joist Hanger?
Joist hangers are framing components formed from metal straps with punched or molded holes for fasteners. They are used in construction by pros and DIYers when framing floors, ceilings, roofs, decks, railings, and numerous other purposes. They help to align, anchor, support, and prevent twisting of horizontal and sloping framing components.
The hangers are usually U-shaped to frame the end of the joist on the bottom and both sides. They are used to attach joists to support components at 90° angles. Most hangers also have outward or inward-folded wings or flanges on both arms of the ‘U’ that form fastening plates.
Holes are spaced on all faces of the U and flanges to provide optimum support when used correctly with the appropriate fasteners. The hangers are typically attached to a vertical structural face and the joists are placed into the U support and fastened into place.
When to Use Joist Hangers?
Joist hangers are used for large or small building projects. The hangers provide a strong, simple, more accurate supportive method of securing horizontal or diagonal components to vertical and horizontal structural support members. They are commonly used for connecting joists, railings, stair stringers, and other timbers to structural members like beams, posts, and walls as well as rim, band, and ledger boards.
The metal hangers are used when wood shrinkage, load, and/or twisting could weaken the connection between connections. End nailing and toe nailing may not be feasible nor as strong as joist hangers.
Hangers are also used when it isn’t practical or aesthetically desirable to have joists or other components on top of beams or walls. For example, fastening joists to the face of beams so they are level with their top edge makes for a thinner floor deck profile.
Are Joist Hangers Required by Code?
Shear loads and twisting have long been a concern when building. Additionally, shrinkage and twisting, along with rot and corrosion, make nails and screws susceptible to failure. The development of joist hangers in the 1960s is a direct result of this concern. They are also an evolution of homemade tin or steel straps used in the past to improve joint support.
Conventional framing where joists or other horizontal structural components have 1-1/2” to 2” or more of their ends supported on beams and/or walls does not require joist hangers. Where that type of support is not possible for design or other reasons, many building departments have updated codes to require the use of appropriate joist hangers. So, check your local codes to ensure compliance.
Different Types of Joist Hangers
There are different types and shapes of joist hangers manufactured from untreated, galvanized, or stainless steel. Environmental conditions and chemical treatment of the timber used often determine the type of metal required. Joist hangers are used to attach wooden components to wood, masonry, or steel.
They are commonly fastened into place with appropriate screws or nails, or even welded into place. The boot or sleeve of many joist hangers have bendable tabs or tags or nail holes that help prevent rotation or movement. Below, is an explanation of some different types of joist hangers commonly available.
Pro Note: Do not use stainless steel fasteners with galvanized brackets and vice versa. Always use the same type of metal fasteners and brackets to prevent galvanic corrosion.
Timber to Masonry Joist Hangers
Timber-to-masonry hangers typically comply with fire regulations. They have legs or flanges bent 90° at the top to hook between brick courses and transfer loads horizontally to masonry walls. Ideal for any masonry structural wall supporting timbers, they are often used for party or firewall applications.
The hangers are available in depths from 4” to 11.8” and widths of 1.5” to 5”. Often of galvanized metal, they are also available in stainless steel. Some are welded, others press formed and bent, and all are available with standard or concealed flanges.
Timber to Timber Joist Hangers
Timber-to-timber or face-mounted hangers are available in untreated, galvanized, and stainless steel, and in colored enamel or powder coating. They commonly are used to strengthen both load and non-load-bearing connections between timbers.
They are simple, easy to use, and fasten to the face of beams or posts, and ledger, rim, or band boards. Most of the joist hangers below fall into this category.
Concealed Joist Hangers
Concealed hangers have their face mounting flanges bent inside the boot so to make a less visible connection between components. The spacing between the metal and wooden pieces allows moisture to escape, minimizing the risk of rot.
The hangers require less space for mounting and provide a stronger connection to ledger, rim, and band boards, and to posts and for rafters and stair stringers. They are commonly available in 3/64” thick galvanized or stainless steel in widths of 1.5” to 4” and lengths of 3” to 9.25”.
45-Degree Angled Joist HangersThere are several kinds of angled joist hangers. One type looks like a standard joist hanger but it is designed for left or right facing 45° angles. They typically have a concealed flange and a visible one and are installed the same way as standard hangers.
The other kind is an adjustable-slope joist hanger. It looks like a strip of metal with concealed flanges and a boot that can be adjusted to different angles or slopes. Both kinds are fabricated of galvanized or stainless steel. The brackets come in sizes to fit single or double 2×6 through 2×10 lumber.
I-joist hangers are designed for use with floor and roofing I-joists. The top of each flange may be bent or bendable to 90° to hook on and be fastened to the top of the support component as well as its face.
The easy-to-use and economical hangers support the full depth of the I-joist and prevent rotation. Commonly manufactured from 18 gauge (3/64”) galvanized or stainless steel, they are available in different depths and widths to meet most requirements.
Corner Joist HangerCorner joist hangers are available in several different designs. They are commonly made of 3/64” thick galvanized or stainless steel for general use or 1/8” for heavy-duty use. Some are fabricated for inside corner use, some for outside, and others for both. None, however, allow end grain nailing into the support component.
The hangers prevent twisting and are attached with appropriate fasteners. An alternative is to use a hidden flange joist hanger mounted flush with the end of the supporting timber to form a 90° corner.
Mini Joist HangerMini joist hangers are small, economical 1/32” to 3/64” thick galvanized or stainless steel metal brackets used to support light loads or timbers over short spans. They have a depth of up to 4” and come in widths of 1.5” to 3”.
They are commonly used to support ceiling joists, railings, studs, in-fill joists, shorter light-load floor joists, hatchways, trimmers, and other small timbers. They have a safe working load of between 300 and 780 lbs.
Long Leg Joist HangerLong leg hangers are available in different sizes of 1/16” thick galvanized or stainless-steel metal to suit different uses. The short-legged ones are 8-1/4” long, standard ones are 11-3/4”, long ones are 17-3/4”, and extended are 23-1/2” in length. They are used to connect larger joists to beams and carry heavier loads.
The legs are pre-punched for fasteners and can be bent to wrap over timbers for greater strength. They are often used for dropped or underslung floors or ceilings, loft conversions, or purlin connections. They have a safe working load of up to 2625 lbs.
Heavy Duty Joist HangerHeavy-duty hangers typically face mount to wood or metal support beams, girders, masonry, or concrete with nails or bolts.
The boot or pocket should cover 2/3rds of the supported timber to prevent twisting or rotation.
Fabricated from 3/32” galvanized or stainless steel, they come in standard and concealed flange formats and are available to support single or double members.
Universal Joist Hanger
Universal joist hangers come in two formats. One is used to attach joists to steel I-beams and is manufactured from 12 or 14-gauge steel. They’re available in several different shapes and can be secured with welds, screws, bolts, or PAF fasteners.
The other type of universal joist hanger is a versatile 18-gauge galvanized steel hanger that can be used to attach joists to either wood or masonry supports. It is a design that can be used as an alternative to other types of connectors.
Saddle Joist HangersNo products found.Saddle joist hangers are designed to support back-to-back joists on both faces of a timber or masonry support component. They are commonly formed from one piece of metal to straddle a specific support width; however, some have an adjustable saddle to accommodate various support widths.
The hangers are manufactured for different joist depths and prevent rotation and lift forces. Saddle hangers are usually fabricated from 18 and 20-gauge galvanized and stainless steel.
Face Fix Joist HangersFace fix hangers attach directly to the face of the support member or structure to provide stability and prevent rotation of joists or beams. They are typically U-shaped with a squared base or boot and the 12 to 20-gauge galvanized or stainless steel sides, bottom, and flanges are punched for standard and large fasteners.
The hangers are available in different dimensions for various timber widths and depths. There are also split or adjustable face fix joist hangers available for non-standard width components.
Joist Hanger Sizes
Joist hangers are available in various widths and depths but most are manufactured for common dimensional lumber used in construction. Hangers are available for double and triple-ply joists or beams, as well as different widths and depths of I-joists and other engineered laminated lumber.
The hangers are usually designed for specific lumber dimensions, so the bottom and sides of the metal stirrup or boot provide adequate support and rotation-resistant surfaces.
Selecting joist hangers can be a bit of a challenge as different manufacturers use different model number identifications. Some even offer the hangers in thicknesses from 12 to 22-gauge galvanized or stainless steel, which affects load capacity.
Additionally, the nominal and actual widths and depths may not be readily identifiable on the label. Another bit of confusion stems from hangers made for rough-sawn lumber and others for sanded or smooth lumber.
Joist hangers are commonly available for 2×4, 2×6, 2×8, and 2×10 dimensional lumber. For larger 2×12 or 2×14 lumber it’s common to use 16-gauge 2×10 hangers.
For doubled timbers, there are 4×4, 4×6, 4×8, and 4×10 hangers, with 4×12 and 4×14 using the 4×10 hanger. Tripled timbers use 6×6, 6×8, and 6×10, while 6×12 and 6×14 utilize the 6×10 brackets.
Hangers can typically be used for their design size as well as the next size up. So, a 2×4 hanger can be used with 2x6s, a 2×6 hanger with 2x8s, and a 2×8 hanger with 2x10s. As noted above, 2×10 hangers are commonly used for 2×12 and 2×14 lumber too. However, the amount of metal resisting rotation is not as great.
Joist Hangers and Corrosion
Pressure-treated lumber is typically used for exterior projects like decks and fire-retardant lumber is used in some interior construction. The chemicals used in both treatments are corrosive to untreated steel, which could cause fasteners or hangers to fail and structures to collapse.
It is recommended that either triple-galvanized or stainless steel hangers with appropriate fasteners be used to prevent corrosion. The lighter single or double-dipped galvanized coating doesn’t withstand the corrosive nature of the chemicals as well as the triple-dipped.
Using untreated steel joist hangers with untreated wood is acceptable, but moisture issues can cause the metal to corrode and timber to rot over time. Additionally, manufacturers of joist hangers strongly recommend that stainless steel components not be used with galvanized materials and vice versa.
The mixing of the two metals can cause electrolytic or galvanic corrosion, which can lead to structural failure. To prevent corrosion, use appropriate fasteners with whichever joist hanger is suitable for the task, don’t mix and match metals.
Deck Joist Hangers for Treated Lumber
The copper in ACQ (alkaline copper quaternay) or CA (copper azole) pressure-treated lumber is more corrosive than the copper in CCA (chromated copper arsenate) treated lumber. Both CA and AQC treatments are about 5 times more corrosive to untreated steel.
The CCA treatment is still available, but no longer used for most residential projects due to its arsenic content. The use of more corrosive treated lumber has led many builders to use the more expensive stainless-steel hangers.
Some manufacturers are producing triple hot-dipped galvanized or G-185 coated hangers and fasteners specifically to withstand the chemicals used in ACQ and CA pressure-treated lumber. Most composite or ceramic-coated fasteners meet or exceed the class rating of 40 recommended for electro-galvanized fasteners, but always check before using.
Many frugal builders and DIYers are using self-adhering joist tape or waterproof membrane with the less expensive double-dipped galvanized hangers and ceramic fasteners. The tape or membrane helps protect the metal from corrosive chemicals, and is less expensive than stainless steel.
Fasteners for Joist Hangers
Attaching joist hangers to structures requires appropriately sized code-compliant fasteners to ensure structural integrity and prevent corrosion. Untreated steel hangers are often used for dry or protected locations, while galvanized hangers are used for both inside and outside tasks more commonly than stainless steel hangers.
The type of fasteners for each metal treatment is similar, but they aren’t necessarily interchangeable. Never use stainless steel fasteners with galvanized hangers or galvanized fasteners with stainless steel hangers.
Mixing the two coatings can cause galvanic or electrolytic corrosion and cause structural failure. Below are different types of fasteners recommended for use when fastening joist hangers.
NailsUse nails with a wider shank and reinforced throat where the head and shank join as they have greater shear strength. Never use roofing nails! They don’t have the required shear strength. 10d and 16d common nails have a diameter of 0.148” and 0.162” respectively, and are commonly used to fasten joist hangers to beams or posts.
16d nails are 3.5” long and 10d are 3” long, so they tend to drive through ledger and rim boards and other single-thickness 2-by lumber. When fastening hangers to single-width 2-by lumber, use #10 1-1/2” x 0.148” nails. They have the same thickness and a shear-load strength of 184 lbs, but won’t penetrate through the wood. Always use nails of the same metal as the joist hanger.
ScrewsScrews for joist hangers are available in uncoated, galvanized, stainless steel, ceramic, or composite-coated treatments. Make sure to use stainless steel fasteners with stainless steel hangers, most other types are fine with steel or galvanized hangers.
Look for screws that are manufactured for use with joist hangers and have high shear-load strength. There are structural screws with thicker screw shanks and strong drive head connections that are ideal for fastening joist hangers into place.
Use a #9 x1-3/8” with a shank diameter of 1/4″ and a shear load strength of 181 lbs or a #9 x1-1/2” with a shank diameter of 0.131” and a shear load of 112 lbs. There’s also the #10 x1-1/2” with a shank diameter of 0.161” and a shear load of 138 lbs or the 1/4″ x1-1/2” with a 1/4” shank and a shear load of 180 lbs. Some require standard screwdrivers and others need hex-head nut drivers.
How to Install Joist Hangers Correctly
Joist hangers make it easier to attach joists, rafters, and other members to structural components. They also improve the connection, prevent rotation, and keep it strong as timbers age, dry, and shrink.
Use hangers sized for the wood they will support and appropriate for the task. Most hangers can hold their design size or one-dimensional size up. Always select fasteners appropriate for the hanger metal, wood treatment, thicknesses, and task.
There are different ways to align joist hangers on structural members. There’s the on-center mark, the single edge mark with an X for the joist, or the edge mark on each side and X in the middle. Whichever method selected, use a square to draw full-length perpendicular lines. The longer lines make it easier to ensure the joist hangers are plumb and not askew.
Measure location based on joist spacing from one end of the structural member to the other and mark for hanger location using one of the above-mentioned methods. Some builders and DIYers attach joist hangers prior to installing ledger boards or other carrying members, some attach the hangers to installed components, and others toenail the joists in place and then install the joist hangers.
Depending on the joist hanger size and type and the joist dimensions, you may wish to use a string line to mark the location of the top or bottom of the hanger. Alternatively, use a dummy block – a short block of wood of the same dimensional lumber as the joists – to place the hangers at the correct depth.
The joist hanger should be squeezed to hug the joist tightly to prevent rotation, hence the use of double-edge marking lines or a dummy block. Many face-mount hangers have a speed prong that can be hammered into the support board to hold it in place prior to driving fasteners.
Use 10d nails for 3” or thicker timbers and #10 1-1/2” x 0.148” nails for single 2-by thicknesses. If you prefer screws, use #9 x1-3/8” with a 1/4″ shank diameter, 1/4″ x1-1/2” with a 1/4” shank diameter, or another joist hanger rated screw. Every hole in the hanger should have a fastener, and remember, never use galvanized with stainless steel.
Joist Hanger Load Capacity
Joist hangers are as strong as the metal thickness they are made of and the diameter and number of fasteners holding them to the support member. The thicker the hanger metal, the greater the load potential. Plus, 16d nails have higher load limits than 10d nails due to their thicker diameter. However, using only two fasteners of any diameter won’t provide the same strength as using a fastener in each hole provided.
Most joist hangers are engineered to carry more than the maximum load of the lumber it is designed to carry. The load capacity also depends on the species, grade, and dimensions of lumber being connected with the hanger.
Hanger limits for joists of Douglas fir often differ from Southern pine, SPF, or Hemlock fir, so always check the manufacturer’s specifications for allowable loads. It should also be noted that using hangers for deeper dimensional lumber doesn’t change the maximum allowable load from that for which it was designed.
Joists carry internal loads so aren’t typically considered structurally load-bearing, so joist hangers also aren’t considered load-bearing. Joist hangers help strengthen the connection. 12-gauge joist hangers have a much higher carrying capacity than the more commonly used 16 or 18-gauge or very light-duty 22-gauge steel hangers.
The Table below identifies the typical minimum load capacities for common joist hangers.
|Joist Hanger Load Capacity
|Joist Hanger Size
|Minimum* Vertical Load Capacity
* Load minimums may vary by Brand.
Popular Joist Hanger Manufacturers
There are numerous manufacturers of joist hangers with a variety of products on the market. The big-box stores tend to be proprietary to one brand, though, so you may need to shop around.
- Simpson Strong-Tie is one of the most popular and trusted manufacturers of joist hangers. They have a full line of hangers, including their ZMax triple-galvanized line. Plus, they have an extensive line of fasteners too.
- USP Structural Connectors are another popular choice with a good range of hangers, including its TZ line of triple-galvanized connectors. MiTek is another popular choice with a popular line of structural connectors, it is also the parent company of USP.
- BPC Fixings is a British manufacturer and a popular choice too with a wide range of joist hangers to choose from, but they may be more difficult to find.
- OZCO Building Products has a line of ornamental wood ties (OWT) that are structural joist hangers in a black corrosion-resistant finish with matching fasteners. Ideal for visible locations.
Alternative to Joist Hangers
Supporting horizontal members on walls or beams, using mortise and tenon secured with wedges or pegs, ledger strips, or sliding dovetails are some common alternatives to using joist hangers. Nails and screws are also common construction tools used for fastening joists to structural members. Two common practices using fasteners are toe-nailing and end-nailing.
Toe-nailing joists to structural members requires setting and driving appropriately sized nails or structural screws on an angle through the edge of the joist near its end and into the support member. Fasteners are driven through both sides of the joist to create an X which helps to minimize twisting and pulling.
Unfortunately, the accuracy of alignment, stability, and attachment strength are not as good as that provided by other methods, although the holding force may be similar. For smaller jobs, some pros or DIYers predrill fastener holes through the joist ends so fastening is easier and more accurate. Additionally, some joist hangers use toe nailing to improve the connection too.
End-nailing is typically used to connect joists and other components to other single-thickness structural components. Fasteners are driven through the face of one piece and into the end grain of a perpendicular or diagonal piece where it butts into the opposing face.
This method is commonly used to attach blocking between members or to attach rim or ledger boards to joist ends. Nailing into the end grain with appropriate fasteners may produce good shear force strength but the connection can become loose as the wood ages, dries, and shrinks. So, components that may experience movement should be toenailed as well or supported in some other manner.