When you're framing a deck, the way you attach joists to the ledger or beam is one of the most critical structural decisions you'll make. The two most common methods — notching the joist to sit on a ledger or beam, or using metal joist hangers — have passionate advocates on both sides. Notching is traditional and can feel simpler, while hangers are code-mandated in many jurisdictions and promise superior strength. But which one actually holds up better over decades of weather, rot, and load? This article breaks down the engineering, the installation pitfalls, and the long-term maintenance realities of each method, so you can choose the right approach for your build.
The fundamental difference between notching and hangers is how the load from the joist gets transferred to the supporting structure. A notched joist creates a horizontal bearing surface that rests directly on the ledger or beam. That bearing surface carries the load in compression — the grain of the wood is being pressed downward into the support. For a properly cut notch, this works well as long as the bearing area is sufficient and the wood remains dry.
A joist hanger, by contrast, transfers load through the hanger's seat and side flanges. The joist sits inside the hanger, and its weight pushes down on the seat. The seat then transfers that force through the hanger's mounting nails or screws into the ledger or beam. This is a shear load on the fasteners — they're being pulled sideways, not pulled out. Hanger manufacturers engineer the seat depth and flange geometry to distribute this load evenly, and the fasteners are rated for specific shear capacities.
With notched joists, the critical failure mode is wood crushing at the bearing point. Southern yellow pine, a common decking wood, has a compressive strength perpendicular to grain of about 700 psi. A standard 2x8 joist bearing on a 1.5-inch wide ledger provides about 10.5 square inches of bearing area. At a typical 40 psf live load, that's adequate in theory. But over time, moisture cycling can soften the wood fibers, reducing that compressive strength by 20-30%. I've seen notched joists that looked fine from above but had the bearing surface compressed by a quarter-inch after 15 years — effectively shortening the joist and creating a sag.
Joist hangers avoid this issue entirely because the load is not bearing on wood fibers but on steel. The seat of a Simpson Strong-Tie LU26 hanger, for example, is rated for over 1,000 pounds of load in shear. The wood inside the hanger still experiences some vertical compression, but it's contained by the side flanges, which prevents the wood from splitting or crushing outward.
If you choose to notch, the International Residential Code (IRC) is blunt about it: the notch cannot be deeper than one-quarter the joist depth, and it must be located in the end third of the span. For a 2x10 (actual depth 9.25 inches), that means a maximum notch depth of 2.3 inches. The remaining uncut portion of the joist at the bearing point must be at least 2 inches thick. These rules exist because a deep notch creates a stress riser at the corner where the notch meets the full-depth joist — that sharp inside corner is where cracks start.
The most insidious problem with notched joists, and the one I see most often in older decks, is rot at the notch. A notch creates a horizontal shelf that traps leaves, dirt, and moisture. Even if you paint or seal the cut, the end grain of the wood at the notch shoulder is highly absorbent. Water wicks into that end grain and travels along the fibers back into the joist. I've disassembled 20-year-old decks where the joist looked fine for the first 6 feet, but the end bearing 8 inches was completely rotted and spongy. The notch had essentially turned the joist end into a wick.
Hangers, by contrast, hold the joist end slightly above the seat. Most hangers have a small gap or "weep hole" in the seat — Simpson Strong-Tie hangers, for instance, have a 1/4-inch drainage hole. Any water that leaks between the joist and the hanger drips out the bottom rather than pooling. In my own deck rebuild five years ago, I switched from notched to hangers precisely because I was tired of replacing rotted joist ends every decade.
Joist hangers are only as good as their installation, and the biggest mistake DIYers make is using the wrong fasteners. Those little nails that come in the hanger box? They are specifically engineered for shear capacity. Simpson Strong-Tie uses 1.5-inch 10d hot-dipped galvanized nails for their standard hangers. Each nail is rated for about 160 pounds in shear. A typical hanger calls for 8 nails (4 on each side flange) plus 2 into the joist — that's a combined shear capacity of around 1,280 pounds. Using a generic 16d nail instead might look the same but has a different head diameter and shank texture, which reduces its pull-through resistance by as much as 40%.
Another error is over-driving the nails so they squeeze the hanger flanges tight against the joist, crushing the wood. The flanges are meant to fit snugly but not so tight that the wood fibers are compressed. Over-driving can reduce the hanger's lateral load capacity by 15-20% because the wood loses its ability to deform slightly under load. Use a hammer, not a nail gun, for hanger nails. Nail guns can over-drive easily.
If the ledger or beam surface is not perfectly flat, or if the joist is slightly bowed, the hanger can end up skewed — one side flange lifts off the wood. A hanger that is not fully seated cannot transfer load evenly. The solution is to shim the hanger with galvanized steel shims (Simpson makes them) or to plane the joist end flat. Never rely on the nails to pull a bowed hanger flat; they will eventually work loose under cyclic loading.
Over 30 years, both methods face wood creep — the slow deformation of wood fibers under sustained load. Notched joists are more susceptible to creep because the bearing surface is a small area of wood fibers that are end-loaded. Hangers distribute the load more evenly across the joist's cross-section and contain the joist laterally, which reduces creep. In a 1999 study from the USDA Forest Products Lab, joist hangers reduced mid-span creep by 18% compared to notched joists in pressure-treated southern yellow pine after 10 years of simulated live load.
The biggest long-term downside of hangers is the potential for galvanic corrosion. If you use untreated steel hangers with ACQ-treated lumber (the common treatment after 2004), the copper in the ACQ reacts with the steel. The result is rapid corrosion of the hanger — I've seen hangers that lost 50% of their flange thickness in 8 years. The solution is to use galvanized or stainless steel hangers with ACQ lumber. Simpson Strong-Tie's ZMAX coating (a hot-dipped galvanized finish) is rated for ACQ contact. If you're building in a coastal environment, upgrade to stainless steel hangers — the extra cost is about $1.50 per hanger, which is trivial compared to replacing a rotted deck beam.
Notched joists have no corrosion risk, obviously, but they have their own long-term issue: seasonal movement. Wood expands and contracts with humidity changes. A notch cut into the joist creates a weak point where the cross-section is reduced. Over decades, this area is more likely to develop cracks as the wood tries to move but is constrained by the bearing surface. I've seen notched joists where a crack started at the inside corner of the notch and propagated 18 inches up the joist. Hangers allow the joist to move more freely within the metal seat, reducing stress concentrations.
If you're pulling a permit (and you should be for any deck attached to a house), the inspector's preferences matter. In most jurisdictions, the IRC requires joist hangers for all end connections where the joist sits on a ledger or beam. Section R507.8 of the 2021 IRC is explicit: "Joist bearing on a ledger or beam shall be attached with approved joist hangers." Notching is still permitted for joists resting on top of beams (like a flush beam), but even then, many local amendments require hangers for all connections.
In practice, I've talked to inspectors in three different states. All of them told me they'd rather see hangers than notches, even when the code allows notching. Their reasoning is consistent: hangers provide a visible, verifiable connection. An inspector can look at a hanger, see the nail pattern, and know immediately that the connection is correct. A notch, by contrast, requires measuring bearing depth, checking for splits, and verifying end-grain sealing — all of which are harder to assess after the decking is installed.
If you notch and the inspector flags it, you may be required to add hangers anyway, which means you'll be retrofitting — a much more difficult job than installing them in the first place. The cost difference between notching (free) and hangers ($1.50 per joist) is not worth the inspection risk.
There's a common belief that notching is faster. In my experience, that's true only if you're an experienced framer with a circular saw and a sharp chisel. Cutting a clean notch requires marking both the depth and the length, making two cross-cuts with the circular saw set to the proper depth, then making rips to remove the waste. Getting the notch tight against the ledger without gaps takes practice. A sloppy notch that leaves a 1/8-inch gap reduces the effective bearing area and creates a spot for water to sit. I've watched beginners spend 10-15 minutes per notch and still end up with a gap.
Hangers, on the other hand, are idiot-proof by comparison. You mark the joist layout on the ledger, hold the hanger in place, drive the nails on the side flanges (3-4 per side), then drop the joist in and add the nails through the joist itself. Total time per hanger: about 3 minutes once you have a rhythm. The learning curve is about 3 hangers. By the fifth one, you'll be fast and accurate.
If you're building a 12-foot deck with 16-inch joist spacing, you'll have about 10 joists. Notching could take you two hours with cleanup. Hangers will take 30 minutes. That extra 90 minutes of your life is worth more than the $15 you saved by not buying hangers.
Despite everything above, there are two situations where notching is the better choice. First, if you are building a ground-level deck that is not attached to the house — a freestanding platform with joists resting on beams — notching the joists to sit flush on the beam is structurally fine. There's no ledger, and the load path is straight down. The rot and inspection concerns are minimal because the deck is low and easily accessible. Second, if you are working with a beam that is wider than the joist and you want the deck surface to be low, notching lets you sit the joist flush with the beam top, keeping the deck height minimal.
For any deck attached to a house, or any deck over 12 inches off the ground, joist hangers are the clear winner. They're faster, they pass inspection every time, they resist rot better, and they transfer load more predictably over decades. Spend the $15 on hangers. Your future self — the one who isn't crawling under the deck in 15 years to replace a rotted joist end — will thank you.
Next time you're at the lumber yard, pick up a box of Simpson Strong-Tie LU26 hangers and a handful of their hot-dipped galvanized nails. Lay out your joist spacing on the ledger with a chalk line, install each hanger level and flush, and set the joists in place. Drive the nails all the way home, but don't over-sink them. Then step back and know that connection is going to outlast the deck boards above it. That's a good feeling.
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