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How To Install, Repair or Replace A Damaged Mailbox Post

Rain... sleet... gloom of night... no matter what the time or weather, one day your mailbox or post will require replacement. Thank you, snow plow... with an assist from the carpenter ants and termites!

The hardest part of a mailbox installation can be removing the old box or post!

So I'm going to make the assumption that you wish to replace the box and the post. If I'm wrong, and you want to do just the box, I will have even less to tell you, but, if you scan down past the sweaty, smelly, earthwormy stuff, you may still pick up a few tips. I don't exactly know where this tale is going, so follow along as best you can, and hopefully we'll arrive at the end together!

Installing a new post and installing a replacement post are about the same,

Should you "call before you dig"??  Maybe... but always exercise caution!

I've received a few notes from readers that it is important to call your local "Call Before You Dig" number to be sure there aren't any utilities beneath your mailbox location.  The fact is that the depth that a typical mailbox or fence is dug (2 - 3 feet) is much shallower than the required depth of any gas, telephone or electric utility.  However, I won't discourage anyone from making this call, especially if you're installing a new mailbox.

You should be aware if there are any customer-installed wires or pipes (such as light posts or underground sprinklers) in the area of the post and exercise caution when digging.  These would NOT appear in a "Call Before You Dig" analysis of your yard!

Removing the old post... pray there's no cement!

Sorry... I can't make this easy! Wiggle it, pray it wasn't set in cement, and pull like heck!! Then again, if you are pretty sure there is no cement, there is a strategy that can work, especially if you have a broken post with only a few inches exposed.  Nail or screw a piece of 2x4 or larger lumber to the post at or within a few inches of ground level. Then, using a big pry bar or the mason's bar, pry the post straight up, using another board, toolbox, or significant other as a fulcrum.

Caution: Seriously.  Don't use a "significant other" as a fulcrum... if you expect your relationship to move to a higher level!!

I once saw a guy screw a piece of 2x4 to a mailbox post and lift it out of the ground with a automotive tire jack!  So let those creative juices flow!

A post set in concrete creates a whole new problem.  If I found one of those foundation-like clumps of rocks and gravel mix when the digging started, my first choice was always to choose a new location for the box!

Occasionally, there just isn't an option and the cement must be removed or moved.  Yes... moved.  Sometimes, it's easier to dig the hole a little wider and muscle the ball of concrete aside.  Install the new post next to it.

US Postal regulations regarding mailbox location and height

In order for the safe and efficient delivery of mail, the US Postal Service has issued regulations regarding curbside deliveries. However, the local post office has the final say in mailbox placement.  The "old guidelines were:

  1. Vertical height from road surface to bottom of mailbox: Between 41" and 45".
  2. Distance from outside edge of curb or edge of road surface to front of mailbox : 6-8"

This requirement dates back to February of 2001.  However, the more recent requirements (12/9/2004) are less specific and do not refer to specifics of height and location.  Instead, they require the post to be approved by the local post office and 2) accessible from the vehicle for curbside delivery such that the letter carrier does not have to leave his vehicle.  That means that any obstruction, including parked cars, snow piles, etc. , give the carrier the option of withholding delivery until the obstruction is removed. (Click HERE for the last known location of these newer requirements.)

If you are installing a post with an extending arm, figure the position based the final position of the box, not just the arm!  Note that the arm will need to be much higher up if you plan to hang the box.  (More on mounting the box below.)

If you feel your situation is unique or would like an exception to the rules, talk to your postmaster or ask your friendly postal carrier for suggestions. (This is when that little bag of Christmas cookies or envelope makes all the difference!)

Creating your own mailbox? Be careful...

If you plan on making a mailbox yourself, you should check with the postmaster or letter carrier to get approval before you spend time and money on it!  A poorly designed mailbox can halt your mail delivery!

Choosing your new mailbox post - wood or "other"?

There are a number of choices for mailbox posts.  The most recent addition is molded plastic.  Some make no pretense about being plastic, using flowing shapes, interesting colors and unique designs with integrated features such as newspaper holders.  Others are made to look like painted cedar mailbox posts but for a fraction of the price and without the durability problems.  As a whole, plastic mailbox posts are extremely durable and will outlast any wood or metal post.

Aluminum and galvanized steel
Metal posts are available in galvanized steel and aluminum.  Both are durable, but the nod goes to aluminum.  Because it doesn't  rust like steel, the finish stays looking good longer.  However, aluminum posts tend to be more expensive.

Wood mailbox posts are the traditional choice, especially for do-it-yourselfers looking for economy.  The cheapest and simplest post is a simple 4x4 or 6x6 post of any wood variety.  A 3/4" - 1" thick pine, plywood or cedar wood base is attached to the top of the post and the mailbox is screwed onto it.  The base should be sized to fit into the recess under the mailbox.  On many boxes, you will need to leave some space at the door end of the base to prevent rubbing.  Test the operation of the door before making the final box installation.

If you have more money to spend or want a more interesting look, you can buy a fancy-schmancy wood posts with a horizontal arm, complex supports and other ornamentation (or you can build one yourself).  These are available in redwood, cedar and various untreated and pressure-treated woods.

Each type of wood has its advantages and disadvantages:

Prepare your mailbox post for burial with the correct underground preservative

There was a time when this was a no-brainer.  My father used to put good ol' creosote on everything, except for my mother's tulip bulbs.  (Or did he?)  It rivaled his use of Mobil red and blue paint! Anyway, it went without saying that the old timers expected the wood to rot, so they prepared for it with creosote... the only available solution.

Today, most wooden fence and mailbox posts are made from either pressure-treated wood or cedar. Somehow, in popular thought, cedar has been compared to pressure-treated wood for rot resistance. Nothing could be further from the truth. CEDAR WILL ROT!! I have replaced untreated cedar mailbox posts less than 5 years old, cedar lamp posts less than 3 years old that were totally rotten, full of ants and all sorts of other awful creepy wormy things. In my neck of the woods, a fine 6x6 cedar mailbox post costs well over $200.00 installed. Expensive ant food, if you ask me!

Pressure-treated mailbox posts do not rot under most circumstances.  (I've never seen it happen in 30 years of installations.) They are more likely to die from snow plow or garbage truck injuries!  However, I have heard rumors that, under some unusual conditions of extreme moisture, they may rot after many years.  So if you have some underground rated preservative around, slap some on that pressure treated post.  Otherwise I wouldn't lose any sleep over it!

What type of preservative should be used underground on my post?

Good old creosote, a staple wood preservative for generations of do-it-yourselfers, has become extinct... joining the dodo bird, 30 cent cigarettes and the $1.00 gallon of gas! However, there are still quality underground preservatives available.  A brand I have used for decades is Woodlife Coppercoat from Rustoleum. Hopefully termites and carpenter ants don't get on some idiot's endangered species list!

Another, somewhat newer product that works quite well and is water-based is Woodlife Creocoat from Wolman.  It is black but unlike Coppercoat is not designed to be overcoated.

(Note:  if the links don't work, it's because Rustoleum has taken over/ merged with Wolman so their internet links are somewhat in "flux".  So do a search if needed.  Thanks and sorry!)

If you have the time, always soak your wood posts!!

Since the end of your post is most vulnerable to water damage, pour some of the preservative in a small pail and set the post into it to soak as long as you can... overnight if possible.   Cut off a few inches from the end of the post immediately before to soaking it for the best results.  Of course, you should also coat the rest of the post right up to ground level for the best results.

DO NOT install a mailbox post in cement unless absolutely necessary!

Or a fence post, for that matter! Think about it. 160 pounds of rock-hard concrete mix, buried 18" into the ground, in the only place the mailman can reach from his truck. Tough luck! So, using the secrets of the Pyramids, you manage to get this now useless clump of lime, gravel, and sand up to ground level. As you marvel at your improvisational skills, there is a lesson to be learned here, and it doesn't only apply to mailbox posts.

If you think that you may have to redo a job again sometime in the near future, plan your repair so that the next time it will be easier... not harder!  After all, do you really think a couple of hundred pounds of cement means as much to a moving vehicle (or the carpenter ants) than it does to your poor overworked back? Hmmm?

NOTE:  If you are installing one of those fancy ornamental iron posts, which generally don't stand upright very well in soil despite what it says on the box,  you can use cement... but just enough to stabilize the post, not enough to anchor the Queen Mary!

Digging the hole the easy way... but not too deep!

I was joking.  There isn't an easy way.  But we're not quitters, right?  Buy or rent a post hole digger so you disturb the minimum amount of soil.  The hole should be no more than 18-24" deep.   You do not have to bury the post down below the frost line!  We're talking mailbox post here, not a house's foundation!

If you have particularly rocky soil (I love New England), you may need a long mason's bar, a rounded heavy steel bar from 4' to 6' long, flattened to a wedge-shape on one end. This can be used to pry out rocks and the flattened butt end can be used for tamping.

On the graphic of the post hole digger (left), notice the black lines on the handles. They are improvised depth indicators... far better than dirtying up your tape measure! If you rent one and it's not already marked, apply pieces of black electrical tape at your desired depth.

Add gravel, level the mailbox post and fill the hole in steps...

It's recommended to put a 4-6 inches of gravel in the bottom of the hole to improve drainage and to keep water from pooling at the bottom of the post. My judgment is that it may not be a bad idea for cedar posts, but for pressure-treated wood it is optional.  If you don't have a bag of gravel handy (or prefer not to steal it from elsewhere in your yard), a bunch of small stones will do as a substitute.

To keep the mailbox post vertically level, I found a nifty little device that straps right onto the mailbox post.  However, an ordinary level will do fine, too.  Check the level every time you tamp down the dirt.  You don't want your mailbox to become another "leaning" tourist attraction!  Don't put the level on the top of the post... the top might not be square!  Always check the level from the side.

Some people screw or clamp boards to the post to hold it upright.  You can also wedge a few rocks around the post in the hole for temporary support.  Or just hold the new post fairly level as you begin filling, making minor corrections as you fill.  (A helper wouldn't hurt, either, if one is available to share the joy!)

Filling the hole around the post should be done in steps, packing or "tamping" down the soil as you fill around the post, 6-12" at a time. If you wait until the hole is full before packing, the post may always be loose. You can use most anything that will fit into the hole to pack the soil... a shovel handle, the but end of your masons bar, 2x4, etc.  Keep checking that level!!

Attaching your mail box on the post...

If you wish to mount your box directly atop the pole or onto the top of an extended arm, you will use method (1).  If you want to hang the box beneath the extended arm, use method (2).

Whichever way you choose, don't ever nail the mailbox to it's support... use galvanized or stainless-steel screws.  If your mailbox does not outlive your post, you want it to be easy to remove.  I have found galvanized square-drive decking screws to be a great choice.

(1)  Mount a board directly on the mailbox post or on the arm extending from the post
If you don't have a board for the post, you must cut a piece of 3/4" plywood or pine that will fit into the base of the mailbox. It should be a tight fit widthwise so the box doesn't bend when you screw it on, and short enough in length so the box door doesn't hit the board when the door opens. Position the board as you like it on the post or arm and secure it with at least 4 wood screws. I personally use #8 or #10 galvanized square drive screws, 2-1/2" -3" long. If you are using a post with an arm, you may want to let the board overhang the end of arm for clearance of the door.

(2)  Hanging  the mailbox under an arm extending from the post
You can purchase a special set of bolts designed for hanging a mailbox at most hardware or home stores. The hardware consists of an eye bolt and an screw eye, interlocked and ready to use. The eye bolt is screwed into the underside of the post arm and the bolt is attached to the top of the mailbox.  It may or may not come with a rubber washer to seal the outside of the hole.

If your hardware store doesn't carry these parts, you can either (1) use an eye bolt on the mailbox and a hook on the post arm, or (2) use an eye bolt and screw eye of the same size and bend either open to allow you to hook them together... then bend them closed. For each eye bolt, you should get two nuts, one for inside and one for outside the box, and a small rubber washer (a faucet washer will do) slightly larger than the nut, for the outside to prevent leaks.

Determine the location of the eye bolts on the box first. Some mailboxes have indentations or raised areas to indicate the suggested location for the eyebolts. Locate and drill the holes in the mailbox. Hold the box up under the arm in the position you want it, and use a pencil to transfer the location of the front-most hole you just made to the underside of the arm, being sure to center it along the width. Measure between the holes on the mailbox, and use this measurement to locate the second hole on the arm. Predrill both holes and install the screw eyes.

Put one nut on each eye bolt, and then push on the rubber washers. Bore out the centers of the washers with a drill if they are too tight for the bolts. Then put the eye bolts through the holes in the mailbox and secure them with the remaining nuts, tightening securely.

NOTE:  You can use a dab of caulk instead of a rubber washer.  The washer, however, will probably last longer.

Last but not least... mailbox numbers and other interesting facts

Again, this regulation can be waived by your local postmaster for the appropriate consideration. (Only kidding!) So it goes.

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