Guide: Can You Notch a 4x4 Railing Post?

While a notched railing post can look aesthetically pleasing, is it the right thing to do? Can you notch a 4×4 railing post? Let’s take a look.

Generally speaking, a railing post should never be notched. It doesn’t matter whether it is a 4×4 railing post or another size. While it can make the construction of railings and fences a little bit easier, it makes the entire structure weaker. In fact, it could make the structure dangerous.

Let’s go into depth on this. This is because a lot of people still notch their railing posts, and we really do have to drum home what a terrible idea it actually is.

What Is a Notched Railing Post?

Just to ensure that we are on the same page, when we talk about notching posts, we are talking about adding a lip to a railing post. This allows the railing post to be brought onto the deck. It creates a snug fit which is very aesthetically pleasing. Although, that is pretty much where the advantages stop.

The only other advantages are that the notched railing post won’t move so much when it is wiggled from side to side, or if it has downward force on it. However, we are really hard-pressed to call these advantages. This is because the whole point of a railing post is to prevent people from falling off of a deck. This means that the real direction you want it to be prevented from moving is backward and forward. A notched railing post doesn’t really accomplish this, as you are about to see.

Why Should You Avoid Notching a Railing Post?

Well, for starters, it is against building codes in most areas. If that doesn’t tell you why you should be avoiding it, we don’t know what will. There are a lot of companies that will never even consider notching a railing post for you. This is because it would be illegal for them to do. This doesn’t stop people that are building their own decks and notching a railing post, though. This is why we want to tell you why it is going to be a terrible idea.

Weak Point

You don’t place a railing post on your deck for fun. You do it to ensure that the deck fencing is held firmly in place. If that fence post goes, then the entire fence goes. This can send somebody falling off of the deck. It is dangerous.

The problem with cutting a notch into a fence post is that you have now created a weak point in the center of it. The wood is going to be much thinner. The problem? That is where the railing post is connected to the deck. This is the absolute last place that you want there to be a weak point. If you lean on that, then you are going to be putting most of your weight on the weakest part of the post. It is liable to pulling away from the deck.

Potential For Cracking

Even when a railing post has been notched properly, there is always the risk of small chips to be taken out of it. There may even be a little bit of cracking. The problem is that the seriousness of these issues may not always be apparent.

If a small crack did start to appear on the wood and it isn’t noticed, that crack doesn’t just disappear. Each time a small amount of force is placed on that railing, the crack is going to get larger. This means that the risk of that fence post just giving away shoots up. You may not even notice that the crack is there and, one day, the fence post just gives away. The rest of the fence is going to be coming down with it.

Water Can Get Under The Lip

This may actually be one of the biggest reasons why you will want to avoid putting a notch on a 4×4 railing post. This problem, much like cracks, is going to be hidden until the last minute.

The outside of a railing post tends to be fairly well protected from water. It may be sealed. The inside isn’t. Over time, water can start to get under the lip of the fence post. This can cause wood rot. Eventually, this will make the railing post incredibly weak and it is just going to break. This problem may happen a lot sooner than you would think too. Serious wood rot can cause a fence post to be destroyed in a year or two.

What Are The Alternatives To Notching a Railing Post?

To be honest, there isn’t really anything similar to notching that you can do. You can’t bring that fence post closer to the deck without notching. So, if you do insist on using a 4×4 railing post, then you are out of luck. Most building codes prevent it anyway.

If you absolutely want that look of notching, then some building codes do allow you to do it with an 8×8 railing post. Obviously, you now have something that is double the size which doesn’t look as great, but at least you will be able to bring it closer to the deck. Although, of course, you do run into the other issues of using a notched railing post e.g. chance of cracking, or moisture gathering.

If you do go down the 8×8 route, then make sure that you use some good, solid bolts to hold the fence post to your deck. If you don’t, then you likely will run foul of the weaker joint, and that is something that you really do not want to have happen!

Conclusion

While you can notch a 4×4 railing post, it is recommended that you avoid it. For starters, it goes against the building code in many places. However, having a notch on a railing post can be seriously dangerous. If you must notch, then use an 8×8 post instead. Even then, you will be taking a risk.

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Guide: Can You Notch a 4×4 Railing Post?