multibank of 6 on posts in ground

Multibank Letterbox Guide

Multibanks provide bulk letterbox solutions for large scale, multi-dwellings like apartment buildings, unit blocks and business complexes. It's an efficient and practical way to provide multiple tenants in one lot with their own compact letterbox, rather than having individual standard letterboxes for everyone.

Heatlie Letterboxes specialises in multibank letterboxes and has a long history of supplying them across not just Adelaide but all over Australia. Chances are you've come across of our multibanks somewhere out there. Our most common clients are strata management corporations who organise for multibanks to be put in where needed. They can vary in size from 2 boxes all the way up to 60 boxes and there are many different ways our clients can customise their multibank to suit their needs.

Let's have a look at all the elements of a multibank and what you need to know when ordering one.


Your multibank can be as small or big as you need it to be, within limitations. We generally would not recommend having more than 6 boxes high, as this would put the top boxes out of reach for the average human and goes against Aus Posts' standard regulations. How far wide you go depends on the mail slot size explained below. Landscape boxes are 100mm wider, meaning less boxes across.

We generally recommend:

Landscape - maximum 7 boxes wide

Portrait - maximum 10 boxes wide

6 wide multibank in grey

6 wide portrait multibank with signage plate

A multibank of 6x10 or 60 boxes, can weigh well over 150kgs. This provides challenges for installation and transport, so we generally recommend splitting it up into two smaller banks that can be installed right next to each other, if you need that many.

Mail Slot Size

As explained above, this dictates the size of the boxes themselves. Here at Heatlie Letterboxes we have either landscape or portrait orientation. This means the mail slot will be as wide as an A4 piece of paper either at landscape orientation, or portrait orientation. This is an important choice because it greatly affects the size of the unit. Portrait boxes are narrower than a landscape box by about 100mm, so the space saving can really add up if you are purchasing a larger bank. 

portrait multibanks boxes installed in the ground

Portrait sized boxes, mounted on posts in the ground.

It's important to note though, that the boxes are still the same size, just with the dimensions flipped. So a portrait box may be 100mm narrower, but it makes up for it by being 100mm deeper. This means that either style of box will be able to fit an A4 piece of paper lying flat in the bottom of the box. It just affects what way it goes in through the slot. This means that any large A4 sized mail will not get crushed or folded in order to fit in the box, no matter what style you go for.


Multibanks can be installed in a variety of ways, and the choice is up to you. It all depends on how much space you have and the context of your building. 

Post Mounted Multibanks

One way is to be mounted on two posts that are bolted onto concrete, or cemented into the ground. You'll often see this with business complexes, aged care facilities and unit blocks in suburban areas, as long as they have the space to do so. 

multibank on posts in ground
Ground mounted, front opening landscape sized multibank.

A common practise for multibanks that are mounted on two posts is to have a signage plate above the bank that displays the street name and number for ease of navigation. See image below. 

An example of a signage plate between two posts. 

Wall Mounted Multibanks

The other option is to have it built in. They can be bolted onto a wall, with the bank protruding out in its entirety, or they can be recessed into the wall so that the front of the letterboxes sit flush with the wall. Obviously, with a recess you need a deep enough wall, and with a protruding one, you need space to keep a decent walkway, as well as a strong enough wall - we wouldn't recommend mounting on gyprock unless the studs can support. These are common with urban apartment blocks and allows the letterboxes to be inside, behind locked doors for added security.

A multibank can also go through a wall, so that it can have its mail slot on one side, and be opened on the other side of the wall. 

multibank on wall
Multibank built into a wall with landscape sized, front opening boxes. 


Another huge benefit with our multibank letterboxes is their ability to be either rear or front opening. You may think this doesn't sound too important, but it is, and it's especially dependent on where it will be installed.

If your multibank is to be installed on a wall, it's pretty much a no-brainer that you need front opening, unless you have the bank open up on the other side of the wall. In this case, a rear opening unit is ideal as it provides extra security. We often see multibanks with attempted break ins where the doors will be bent upwards by a screwdriver.

Having a rear opening door on the other side of a wall where the public can't get to, is a good way to stop this. At the end of the day this all comes down to where it is installed and what is practical for the tenants.

multibank rear opening
multibank rear opening
A multibank of six, with rear opening doors.


Multibank cladding is the layer that surrounds the outside of the unit. It provides a protective layer and also finishes it off nicely for an smooth look. We offer either no cladding at all, a basic 1mm cladding or a 32mm SHS cladding for ultimate protection.

Please note that not all these cladding options are available to purchase through our website due to conditional limitations. If you would like to purchase cladding with your multibank please contact us first. 

No cladding will leave the bolts and rivets that we use to assemble to bank exposed on the outside and is the cheapest option. This is available for all installation and mounting types. 

Basic cladding will cover the boxes with a 1mm sheet of aluminium that surrounds the bank. This provides a nice smooth look and is also a bit sturdier and vandal resistant. This can be put on post mounted or wall mounted banks, but is not necessary for recessed or through wall installations.

Advanced cladding is a 32mm square hollow tube that provides the ultimate protection from vandalism. It is only available for wall mounted boxes as it does not work well with posts and is not necessary for built in options. 

multibank with cladding
1mm thick cladding on multibank
multibank with no cladding
Multibank without cladding

advanced cladding multibank

Advanced cladding on a wall mounted multibank


Multibanks are rarely purchased in anything too wild when it comes to colours. We have our full COLORBOND® range available, however we usually just see black, Monument®, and Surfmist®. Most people stick with neutral colours that won't attract too much attention, and work well with their surrounding urban environment. 

Numbering and Text

Traditionally, most multibanks employ a black vinyl strip that runs across the entirety of the bank, with smaller white vinyl stick on numbers and lettering. You've most likely seen this, it's a very common style of numbering multibanks.

However, Heatlie Letterboxes is trying to expand into more stylish looks, ditching the black strips and offering larger vinyl stick on numbers with a choice of colour and font. This makes it more pleasing to the eye, provides customisation ability and is also easier for both tenants and posties to find the right box.

Our vinyl numbering options include:

Colour: Gold, Black, Silver, White, Charcoal Grey

Size: 25mm (max. 13 characters), 15mm (max. 22 characters), 10mm (max. 34 characters)

Font: Arial, Century Gothic, Times New Roman

Location on boxes: Centered, Left Aligned

multibank numbering styles

Front opening, landscape, multibank built onto wall with 25mm, black, Arial, left aligned numbering.

Locking System

The last thing to decide, as you do with all our other standard letterboxes, is the lock type. We offer a key lock that includes 2 keys for each box, or a latch lock where tenants can attach their own padlock or have no lock way of locking their letterbox at all if they want. 


We manufacture our multibanks to precise dimensions that adhere to Aus Post's regulations. There are two sizes, and below is a guide that shows the total dimensions of a bank depending on the layout.

Made to order, Australian Made Multibanks

All our multibank letterboxes are made to your specifications right here in our North Plympton, South Australia factory. We fabricate, treat and powder coat all our own metals in order to craft your letterboxes. We also offer installation in the Adelaide metro area for most of our multibanks and we are happy to discuss this if you need. 

As you can see, there are a lot of elements that make up a multibank letterbox. This is for good reason, as everyone has a different situation and needs something tailored to suit them. We are always open to chat about the options and provide deeper insight, just give us a call or drop us an email!

Check out our multibanks today!

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